WO2013160662A1 - Assembly for electroanalysis of an analyte - Google Patents

Assembly for electroanalysis of an analyte Download PDF

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Publication number
WO2013160662A1
WO2013160662A1 PCT/GB2013/051006 GB2013051006W WO2013160662A1 WO 2013160662 A1 WO2013160662 A1 WO 2013160662A1 GB 2013051006 W GB2013051006 W GB 2013051006W WO 2013160662 A1 WO2013160662 A1 WO 2013160662A1
Authority
WO
WIPO (PCT)
Prior art keywords
assembly
conducting layer
layer
electrical contact
insulating capping
Prior art date
Application number
PCT/GB2013/051006
Other languages
French (fr)
Inventor
Neville John Freeman
Stephen Owen Lock
Original Assignee
Nanoflex Limited
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Nanoflex Limited filed Critical Nanoflex Limited
Publication of WO2013160662A1 publication Critical patent/WO2013160662A1/en

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/26—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
    • G01N27/28—Electrolytic cell components
    • G01N27/283—Means for supporting or introducing electrochemical probes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
    • B01L3/00—Containers or dishes for laboratory use, e.g. laboratory glassware; Droppers
    • B01L3/50—Containers for the purpose of retaining a material to be analysed, e.g. test tubes
    • B01L3/502—Containers for the purpose of retaining a material to be analysed, e.g. test tubes with fluid transport, e.g. in multi-compartment structures
    • B01L3/5027—Containers for the purpose of retaining a material to be analysed, e.g. test tubes with fluid transport, e.g. in multi-compartment structures by integrated microfluidic structures, i.e. dimensions of channels and chambers are such that surface tension forces are important, e.g. lab-on-a-chip
    • B01L3/502715—Containers for the purpose of retaining a material to be analysed, e.g. test tubes with fluid transport, e.g. in multi-compartment structures by integrated microfluidic structures, i.e. dimensions of channels and chambers are such that surface tension forces are important, e.g. lab-on-a-chip characterised by interfacing components, e.g. fluidic, electrical, optical or mechanical interfaces
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/26—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
    • G01N27/28—Electrolytic cell components
    • G01N27/30—Electrodes, e.g. test electrodes; Half-cells
    • G01N27/307—Disposable laminated or multilayered electrodes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
    • B01L2200/00—Solutions for specific problems relating to chemical or physical laboratory apparatus
    • B01L2200/06—Fluid handling related problems
    • B01L2200/0689—Sealing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
    • B01L2300/00—Additional constructional details
    • B01L2300/06—Auxiliary integrated devices, integrated components
    • B01L2300/0627—Sensor or part of a sensor is integrated
    • B01L2300/0645—Electrodes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
    • B01L2300/00—Additional constructional details
    • B01L2300/08—Geometry, shape and general structure
    • B01L2300/0809—Geometry, shape and general structure rectangular shaped
    • B01L2300/0816—Cards, e.g. flat sample carriers usually with flow in two horizontal directions
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
    • B01L2300/00—Additional constructional details
    • B01L2300/18—Means for temperature control
    • B01L2300/1805—Conductive heating, heat from thermostatted solids is conducted to receptacles, e.g. heating plates, blocks
    • B01L2300/1822—Conductive heating, heat from thermostatted solids is conducted to receptacles, e.g. heating plates, blocks using Peltier elements

Definitions

  • the present invention relates to an assembly (eg a sensor assembly) for electroanalysis of an analyte.
  • Electrodes for sensor devices exhibiting high performance and utility. Whilst these sensor devices are relatively simple in terms of components, the electrode design is a radical departure from conventional formats where typically the electrode is embedded in the end face of a cylinder or printed on a polymer substrate providing a relatively long 'tail' for the provision of an edge or end connector.
  • One such electrode design made possible by modern fabrication techniques is a planar electrode.
  • failures which may lead to distorted output from a silicon based sensor device. These include failure to (1) make good electrical contact with the silicon substrate, (2) prevent the analyte coming into contact with the electrical contact region or (3) fully contact the analyte with the
  • the present invention seeks to optimise the output from a planar electrode by providing an assembly which serves to isolate (eg seal) the electrical contact region of a conducting layer from its electroanalytical interrogation region. More specifically the assembly deploys a planar gasket which provides discrete access to the electroanalytical interrogation region and to the electrical contact region.
  • the present invention provides an assembly for electroanalysis of an analyte comprising: a planar electrode which includes a conducting layer and an insulating substrate layer, wherein the planar electrode is configured to discriminate an electrical contact region of the conducting layer and an electroanalytical interrogation region of the conducting layer; a recessed holder in which the planar electrode is recess mounted flushly whereby to facilitate access to the electrical contact region and the
  • an elongate probe including a radial socket in which is inserted radially the recessed holder and an axial bore, wherein a floor of the radial socket includes a radial entry port for the analyte and a chamber spaced apart from the radial entry port and in communication with the axial bore; an electrical connector mounted in the chamber substantially flush with the floor, wherein the electrical connector is connectable to an electrical signal carrier extending through the axial bore; and a planar gasket sandwiched between the recessed holder and the floor of the radial socket, wherein the planar gasket is apertured to provide the analyte with discrete access to the electroanalytical interrogation region and to provide the electrical connector with discrete access to the electrical contact region.
  • the assembly is advantageously robust and enables the planar electrode to give enhanced signal to noise ratios (sensitivity) during electroanalysis.
  • the assembly is straightforward to machine at low cost and fault tolerant in terms of construction errors.
  • the elongate probe may be substantially cylindrical.
  • the radial socket may be a semi-cylindrical socket.
  • the axial bore may be an axial stepped bore.
  • the recessed holder may have a mounting face ⁇ eg a planar mounting face) with a recess in which the planar electrode is mounted flush with the mounting face.
  • a mounting face ⁇ eg a planar mounting face
  • one or more packing shims may be seated in the recess to ensure that the planar electrode is then mountable flush with the mounting face.
  • the recessed holder may be semi-cylindrical.
  • a plurality of positioning lugs may be provided in the mounting face to ensure precise positioning of the recessed holder during assembly.
  • a guide tongue may be provided on an end face (or each end face) to ensure precise positioning of the recessed holder during assembly.
  • the radial socket may be provided with a groove to
  • each of the protuberant connector pins is biassed into electrical connection with the planar electrode.
  • each of the protuberant connector pins may be spring-loaded.
  • the planar electrode has at least one or two dimensions on the micrometer to nanometer scale.
  • the planar electrode is a planar microelectrode or nanoelectrode.
  • the planar electrode has a laminate structure and further includes a first insulating capping layer, wherein the conducting layer is a first conducting layer capped by the first insulating capping layer and substantially sandwiched by at least the first insulating capping layer such as to leave exposed only the electrical contact region of the first conducting layer and wherein the electroanalytical interrogation region is an array of etched voids extending through at least the first insulating capping layer and the first conducting layer, wherein each void is partly bound by a surface of the first conducting layer which acts as an internal submicron electrode.
  • the layers of the laminate structure may be successively fabricated (eg cast, spun, sputtered, grown or deposited) on each other according to standard techniques. Printed polymer techniques may be deployed.
  • the planar electrode includes: a plurality of conducting layers (which may be the same or different) including the first conducting layer and a plurality of insulating capping layers including the first insulating capping layer, wherein the plurality of conducting layers and the plurality of insulating capping layers are alternating in the laminate structure, wherein each conducting layer is sandwiched to leave exposed only an electrical contact region and the array of etched voids extends through the plurality of insulating capping layers and the plurality of conducting layers, wherein each void is partly bound by a surface of each of the plurality of conducting layers which acts as an internal submicron electrode.
  • the number of internal submicron electrodes in each void may be one, two, three, four or five (or more). Such embodiments may be formed by successive lamination (eg deposition or growth) of the conducting layers and insulating capping layers.
  • the dimensions and absolute spatial locations within the void and relative spatial locations of each of the internal submicron electrodes may be precisely defined enabling independent optimisation of the electroanalysis of multiple analytes.
  • the planar electrode further includes: a second conducting layer, wherein the first conducting layer is sandwiched to leave exposed only a first electrical contact region and the second conducting layer is sandwiched to leave exposed only a second electrical contact region, wherein the array of etched voids extends through the first conducting layer, the first insulating capping layer and the second conducting layer, wherein each void is partly bound by a surface of the first conducting layer which acts as an internal submicron electrode and/or by a surface of the second conducting layer which acts as an internal submicron electrode.
  • the first conducting layer and second conducting layer may be substantially coplanar (eg laterally spaced apart).
  • the first conducting layer and second conducting layer may be non-coplanar (eg axially spaced apart, preferably substantially co-axially spaced apart). This may require multilevel metal interconnect.
  • the planar electrode includes: a second conducting layer and a second insulating capping layer, wherein the first conducting layer is
  • first conducting layer and second conducting layer may be substantially coplanar (eg laterally spaced apart).
  • the first conducting layer and second conducting layer may be non-coplanar (eg axially spaced apart, preferably substantially co-axially spaced apart). This may require multilevel metal interconnect.
  • the array of etched voids is a plurality of discrete sub-arrays of etched voids.
  • the array (or each sub-array) may be a linear or staggered (eg herringbone) pattern.
  • the array (or each sub-array) may be a cubic pattern.
  • the array (or each sub-array) may be a multi-dimensional (eg bi-dimensional) array.
  • the array of voids may be mechanically or chemically etched according to the desired application.
  • Each void may be an aperture, through-hole, well, tube, capillary, pore, bore or trough.
  • each etched void is a well.
  • the well may terminate in an insulating capping layer or the insulating substrate layer.
  • the well may terminate in a conducting layer which provides an internal submicron electrode in the base of the well.
  • the (or each) conducting layer may increase in thickness away from the voids.
  • the (or each) conducting layer is a substantially planar conducting layer.
  • the (or each) conducting layer may be metallic.
  • the conducting layer may be composed of a noble metal such as platinum, gold or silver, a metal nitride (eg titanium nitride), carbon, graphite, graphene or a metal oxide.
  • the (or each) conducting layer may be an ion exchange polymer.
  • the (or each) conducting layer may be a functionalised (eg chemically or biologically functionalised) metal.
  • the (or each) insulating capping layer may be ceramic or polymeric (eg an ion exchange resin).
  • the (or each) insulating capping layer may be composed of silicon dioxide, silicon nitride or poly(ethylenetetraphthalate).
  • the (or each) insulating capping layer may be reagent-loaded or functionalised to suit particular applications.
  • the electrical contact region is an electrical contact lip.
  • the electrical contact lip may be a peripheral contact edge such as a square contact edge of the conducting layer.
  • the electrical contact lip may be a wide area electrical contact lip (eg the electrical contact lip may extend along substantially the entire length of the periphery of the planar electrode).
  • the electrical contact lip may be substantially T-shaped.
  • the or each submicron electrode is typically partly or wholly annular.
  • the (or each) conducting layer may be substantially rectangular, T-shaped, serpentine or digitated.
  • a serpentine or digitated conducting layer may usefully provide an array of voids with different combinations of internal submicron electrodes on the same level.
  • the first conducting layer is substantially
  • the array of etched voids extends through only the first insulating capping layer and the first conducting layer.
  • the first conducting layer is fabricated on the insulating substrate layer and is substantially sandwiched by the first insulating capping layer and the insulating substrate layer such as to leave exposed only an electrical contact region of the first conducting layer.
  • the planar electrode further comprises: a second insulating capping layer fabricated on the insulating substrate layer, wherein the first conducting layer is fabricated on the second insulating capping layer and is substantially sandwiched by the first insulating capping layer and the second insulating capping layer such as to leave exposed only an electrical contact region of the first conducting layer.
  • the planar electrode further comprises: a second insulating capping layer, wherein the first conducting layer is fabricated on the second insulating capping layer and is substantially
  • a second conducting layer wherein the second conducting layer is fabricated on the insulating substrate layer and is substantially sandwiched by the second insulating capping layer and the insulating substrate layer such as to leave exposed only an electrical contact region of the second conducting layer, wherein the array of etched voids extends through at least the first insulating capping layer, the first conducting layer and the second insulating capping layer, wherein each void is partly bound by a surface of the first conducting layer which acts as an internal submicron electrode.
  • the array of etched voids extends through only the first insulating capping layer, the first conducting layer and the second insulating capping layer.
  • the array of etched voids extends through the first insulating capping layer, the first conducting layer, the second insulating capping layer and the second conducting layer, wherein each void is partly bound by a surface of the first conducting layer which acts as a first internal submicron electrode and by a surface of the second conducting layer which acts as a second internal submicron electrode.
  • the planar electrode further comprises: a second conducting layer, wherein the first conducting layer is digitated and the second conducting layer is digitated, wherein the first conducting layer and the second conducting layer are interdigitally fabricated on the insulating substrate layer and are substantially sandwiched by the first insulating capping layer and the insulating substrate layer such as to leave exposed only an electrical contact region of the first conducting layer and an electrical contact region of the second conducting layer, wherein the array of etched voids extends through the first insulating capping layer, the first conducting layer and the second conducting layer, wherein each void is partly bound by a surface of the first conducting layer which acts as a first internal submicron electrode and is partly bound by a surface of the second conducting layer which acts as a second internal submicron electrode.
  • the planar electrode further comprises: a second conducting layer, wherein the second conducting layer is substantially coplanar with the first conducting layer, wherein each of the first conducting layer and the second conducting layer is capped by the first insulating capping layer and is
  • first insulating capping layer substantially sandwiched by at least the first insulating capping layer such as to leave exposed only an electrical contact region of the first conducting layer and an electrical contact region of the second conducting layer respectively, wherein one or more first etched voids extend through the first insulating capping layer and the first conducting layer and one or more second etched voids extend through the first insulating capping layer and the second conducting layer, wherein each first etched void is partly bound by a surface of the first
  • each second etched void is partly bound by a surface of the second conducting layer which acts as an internal submicron electrode.
  • each of the first conducting layer and the second conducting layer is substantially sandwiched by only the first insulating capping layer such as to leave exposed only an electrical contact region of the first conducting layer and an electrical contact region of the second conducting layer respectively.
  • the insulating substrate layer is typically composed of silicon, silicon dioxide or a polymeric material (such as polyester or polyimide).
  • a polymeric material such as polyester or polyimide.
  • the insulating substrate layer is composed of silicon.
  • the assembly further comprises an electrically conductive sleeve in electrical contact with the elongate probe and recessed holder, wherein the electrically conductive sleeve is electrically grounded.
  • the electrically conductive sleeve advantageously reduces electromagnetic noise.
  • the electrically conductive sleeve substantially envelopes the elongate probe and recessed holder.
  • the electrically conductive sleeve is an electrically conductive mesh sleeve.
  • An electrically conductive mesh sleeve has the advantage of not hindering the access of the analyte to the radial entry port.
  • the assembly further comprises a manifold housed in the radial entry port, wherein the manifold is equipped with an injection port (eg a low or zero volume injection port) for delivering analyte and an outlet port.
  • the manifold is dismountably housed in the radial entry port.
  • injection port and outlet port are disposed so as to be
  • the manifold rests on an apron of the planar gasket at the base of the radial entry port.
  • This embodiment is useful for interrogating a very small volume of analyte.
  • injection port and outlet port are connected to a flow system.
  • the manifold may include a reference electrode which contacts the analyte opposite the electroanalytical interrogation region.
  • the manifold may be secured in the radial entry port using fasteners such as bolts or by a brace which surrounds the elongate probe.
  • the assembly further comprises a temperature controller for controlling the temperature of the planar electrode, wherein the temperature controller is in intimate thermal contact with a surface of the recessed holder.
  • the temperature controller may include a thermally conductive saddle in intimate thermal contact with a surface of the recessed holder, a temperature probe (eg a thermistor or Pt 100 sensor) inserted in the thermally conductive saddle and an active temperature device (eg a simple heater, a Peltier or a thermoelectric cooler) mounted on the thermally conductive saddle.
  • the thermally conductive saddle may be composed of a material which is a good thermal conductor (eg stainless steel).
  • the temperature controller may be insulated using (for example) a closed cell polymer such as PolyfoamTM.
  • the exhaust of the active temperature device may be vented or actively cooled/heated by (for example) a fan to provide highly precise temperature control.
  • the thermally conductive saddle may be positioned alongside the manifold.
  • the assembly is adapted to restrain the recessed holder in the radial socket.
  • the recessed holder may be restrained in the radial socket with a constant force sufficient to assist the planar gasket to provide the analyte with discrete access to the electroanalytical interrogation region and to provide the electrical connector with discrete access to the electrical contact region.
  • the recessed holder may be fastened to the floor of the radial socket.
  • the recessed holder may be restrained in the radial socket by a snap-fit or clip-close arrangement.
  • planar gasket is composed of Teflon, PTFE, Viton, silicone or nitrile rubber.
  • Figure 1 shows a plan view of a planar electrode of a first embodiment of the assembly of the invention
  • Figures 2 and 3 show a side elevation, plan view, end elevation and perspective view of a recessed holder of the first embodiment of the assembly of the invention
  • Figure 4 shows a plan view and side elevation of the planar electrode mounted in the recessed holder
  • Figure 5 shows a plan view of a planar gasket of the first embodiment of the assembly of the invention
  • Figure 6 shows a plan view and side elevation of the position of the planar gasket when the planar electrode is mounted in the recessed holder
  • Figure 7 shows an elongate probe of the first embodiment of the assembly of the invention
  • Figure 8 shows a side elevation of the first embodiment of the assembly of the invention
  • Figure 9 shows an end elevation of the first embodiment of the assembly of the invention.
  • Figure 10 shows a side elevation of a second embodiment of the assembly of the invention which includes a manifold
  • Figure 11 shows an end elevation of the second embodiment of the assembly of the invention
  • Figure 12 shows a plan view of the manifold of the second embodiment of the assembly of the invention.
  • Figure 13 shows a side elevation of a third embodiment of the assembly of the invention which includes a temperature controller
  • Figure 14 shows an end elevation of the third embodiment of the assembly of the invention.
  • FIG. 1 shows a plan view of a planar electrode 1 of a first embodiment of the assembly of the invention.
  • the planar electrode 1 has a laminate structure with a silicon substrate layer, a lOOOnm silicon dioxide insulating capping layer, a 50 nm platinum conducting layer and a 500 nm silicon nitride insulating capping layer.
  • the planar electrode 1 is configured to expose only an electrical contact lip 2 and to discriminate an electroanalytical interrogation region 3 of the conducting layer.
  • the electroanalytical interrogation region 3 is an array of wells formed by etching through the silicon nitride insulating capping layer, the platinum conducting layer and 500 nm into the silicon dioxide insulating capping layer.
  • Figures 2 and 3 show a recessed holder 21 of the first embodiment of the assembly of the invention.
  • the recessed holder 21 is semi-cylindrical and has a planar mounting face 26.
  • the mounting face 26 has a recess 22 in which the planar electrode 1 is recess mountable.
  • the planar electrode 1 is shown recess mounted in the recess 22 of the recessed holder 21 in Figure 4.
  • a packing shim 41 is placed in the recess 22 to ensure that the planar electrode 1 is flush with the mounting face 26. In other embodiments, the planar electrode 1 may be flush with the mounting face 26 without the need for a packing shim.
  • a pair of holes 27 enables the recessed holder 21 to be held in place during assembly.
  • Two pairs of counterbore holes 24 receive retaining screws (not shown) to secure the assembly with a constant force between the recessed holder 21 and the elongate probe.
  • Figure 5 shows a plan view of a planar gasket 50 of the first embodiment of the assembly of the invention.
  • a large aperture 51 provides discrete access to the electroanalytical interrogation region 3.
  • a small aperture 52 provides discrete access to the electrical contact lip 2. Cut away portions 53 accommodate the positioning lugs 25 in the mounting face 26 of the recessed holder 21.
  • Four apertures 55 allow the retaining screws to pass through.
  • Figure 6 shows the position of the planar gasket 50 when the planar electrode 1 is recess mounted in the recessed holder 21.
  • FIG. 7 shows an elongate probe 70 of the first embodiment of the assembly of the invention.
  • the elongate probe 70 is substantially cylindrical and is equipped with a semi-cylindrical socket 71 in which is radially insertable the recessed holder 21.
  • the elongate probe 70 includes an axial stepped bore 72.
  • a floor 73 of the semi-cylindrical socket 71 includes a radial entry port 74 and a chamber 75 spaced apart from the radial entry port 74.
  • the chamber 75 is accessible from the axial stepped bore 72.
  • a pair of grooves 77 serves to accommodate the guide tongues 23 of the recessed holder 21.
  • Four apertures 700 receive the retaining screws.
  • an electrical connector 79 is shown mounted in the chamber 75 substantially flush with the floor 73 with the exception of a pair of protuberant connector pins 78.
  • the protuberant connector pins 78 make electrical contact with the electrical contact lip 2 of the planar electrode 1.
  • the electrical connector 79 is connected to electrical signal wire in one or more lead-out cables (not shown) before the electrical connector 79 is mounted in the chamber 75.
  • the lead-out cables extend through the axial stepped bore 72 optionally through a cable gland and are terminated in a BNC jack plug connector to make connection to electroanalytical instrumentation such as a potentiostat.
  • FIGS 8 and 9 show side and end elevations of the first embodiment of the assembly of the invention 80 respectively.
  • the assembly 80 is assembled by inserting the recessed holder 21 radially into the semi-cylindrical socket 71 of the elongate probe 70.
  • the walls of the recessed holder 21 are a tight-fit to the walls of the semi-cylindrical socket 71 to withstand deformation during assembly or tightening of the retaining screws.
  • the planar gasket 50 is sandwiched between the recessed holder 21 and elongate probe 70.
  • the large aperture 51 in the planar gasket 50 provides analyte A fed into the radial entry port 74 with discrete access to the electroanalytical interrogation region 3.
  • the small aperture 52 in the planar gasket 50 provides the protuberant connector pins 78 of the electrical connector 79 with discrete access to the electrical contact region 2 to effect electrical connection with the planar electrode 1.
  • the planar electrode 1 may be interrogated when the electroanalytical interrogation region 3 has been discretely accessed by the analyte A. This may be achieved by immersing the assembly 80 in the analyte A up to and beyond the radial entry port 74 (eg by vertical dipping) or by holding the assembly 80 horizontally and dropping analyte A into the radial entry port 74 which acts as a well.
  • the analyte A should cover the entirety of the electroanalytical interrogation region 3.
  • Figures 10 and 11 show a second embodiment of the assembly of the invention 100.
  • the assembly 100 is identical to the assembly of the first embodiment 80 but additionally includes a manifold 101 housed in the radial entry port 74.
  • the manifold 101 is equipped with an injection port 102 for delivering analyte A and an outlet port 103.
  • the injection port 102 and the outlet port 103 are disposed so as to be diametrically opposed in the radial entry port 74.
  • the manifold 101 rests on an apron 105 of the planar gasket 50 at the base of the radial entry port 74 which makes it useful for interrogating a very small volume of analyte A (see Figure 12).
  • FIGS 13 and 14 show a third embodiment of the assembly of the invention 120.
  • the assembly 120 is identical to the assembly of the first embodiment 80 but additionally includes a temperature controller.
  • the temperature controller comprises a thermally conductive saddle 135, a temperature probe 131 mounted in the thermally conductive saddle 135 and an active temperature device 130 mounted on the thermally conductive saddle 135.
  • the temperature probe 131 communicates with the input side 132 of a drive controller 133 which
  • the thermally conductive saddle 135 is fastened to the elongate probe 70 using screws or bolts or a brace which extends around the elongate probe 70.
  • the temperature probe 131 may be a thermistor or PtlOO sensor and the active temperature device 130 is a simple heater, a Peltier or a thermoelectric cooler.
  • the exhaust side (the underside in Figure 13) when using a Peltier or thermoelectric cooler should be cooled either passively through convection or actively using a fan.

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Abstract

The present invention relates to an assembly (eg a sensor assembly) for electroanalysis of an analyte.

Description

ASSEMBLY FOR ELECTROANALYSIS OF AN ANALYTE
The present invention relates to an assembly (eg a sensor assembly) for electroanalysis of an analyte.
Modern fabrication techniques such as silicon foundry techniques are providing electrodes for sensor devices exhibiting high performance and utility. Whilst these sensor devices are relatively simple in terms of components, the electrode design is a radical departure from conventional formats where typically the electrode is embedded in the end face of a cylinder or printed on a polymer substrate providing a relatively long 'tail' for the provision of an edge or end connector. One such electrode design made possible by modern fabrication techniques is a planar electrode.
There are several failures which may lead to distorted output from a silicon based sensor device. These include failure to (1) make good electrical contact with the silicon substrate, (2) prevent the analyte coming into contact with the electrical contact region or (3) fully contact the analyte with the
electroanalytical interrogation region. The provision of an assembly which adequately addresses these failures represents a significant technical challenge.
The present invention seeks to optimise the output from a planar electrode by providing an assembly which serves to isolate (eg seal) the electrical contact region of a conducting layer from its electroanalytical interrogation region. More specifically the assembly deploys a planar gasket which provides discrete access to the electroanalytical interrogation region and to the electrical contact region.
Thus viewed from a first aspect the present invention provides an assembly for electroanalysis of an analyte comprising: a planar electrode which includes a conducting layer and an insulating substrate layer, wherein the planar electrode is configured to discriminate an electrical contact region of the conducting layer and an electroanalytical interrogation region of the conducting layer; a recessed holder in which the planar electrode is recess mounted flushly whereby to facilitate access to the electrical contact region and the
electroanalytical interrogation region;
l an elongate probe including a radial socket in which is inserted radially the recessed holder and an axial bore, wherein a floor of the radial socket includes a radial entry port for the analyte and a chamber spaced apart from the radial entry port and in communication with the axial bore; an electrical connector mounted in the chamber substantially flush with the floor, wherein the electrical connector is connectable to an electrical signal carrier extending through the axial bore; and a planar gasket sandwiched between the recessed holder and the floor of the radial socket, wherein the planar gasket is apertured to provide the analyte with discrete access to the electroanalytical interrogation region and to provide the electrical connector with discrete access to the electrical contact region.
The assembly is advantageously robust and enables the planar electrode to give enhanced signal to noise ratios (sensitivity) during electroanalysis. The assembly is straightforward to machine at low cost and fault tolerant in terms of construction errors.
The elongate probe may be substantially cylindrical. The radial socket may be a semi-cylindrical socket. The axial bore may be an axial stepped bore.
The recessed holder may have a mounting face {eg a planar mounting face) with a recess in which the planar electrode is mounted flush with the mounting face. Where necessary, one or more packing shims may be seated in the recess to ensure that the planar electrode is then mountable flush with the mounting face.
The recessed holder may be semi-cylindrical. A plurality of positioning lugs may be provided in the mounting face to ensure precise positioning of the recessed holder during assembly. A guide tongue may be provided on an end face (or each end face) to ensure precise positioning of the recessed holder during assembly. The radial socket may be provided with a groove to
accommodate the guide tongue.
Typically the electrical connector is mounted in the chamber flush with the floor with the exception of a pair of protuberant connector pins which are provided with discrete access to the electrical contact region to effect electrical
connection with the planar electrode. Preferably each of the protuberant connector pins is biassed into electrical connection with the planar electrode. For example, each of the protuberant connector pins may be spring-loaded. Preferably the planar electrode has at least one or two dimensions on the micrometer to nanometer scale. Preferably the planar electrode is a planar microelectrode or nanoelectrode.
In a preferred embodiment, the planar electrode has a laminate structure and further includes a first insulating capping layer, wherein the conducting layer is a first conducting layer capped by the first insulating capping layer and substantially sandwiched by at least the first insulating capping layer such as to leave exposed only the electrical contact region of the first conducting layer and wherein the electroanalytical interrogation region is an array of etched voids extending through at least the first insulating capping layer and the first conducting layer, wherein each void is partly bound by a surface of the first conducting layer which acts as an internal submicron electrode.
The layers of the laminate structure may be successively fabricated (eg cast, spun, sputtered, grown or deposited) on each other according to standard techniques. Printed polymer techniques may be deployed.
Preferably the planar electrode includes: a plurality of conducting layers (which may be the same or different) including the first conducting layer and a plurality of insulating capping layers including the first insulating capping layer, wherein the plurality of conducting layers and the plurality of insulating capping layers are alternating in the laminate structure, wherein each conducting layer is sandwiched to leave exposed only an electrical contact region and the array of etched voids extends through the plurality of insulating capping layers and the plurality of conducting layers, wherein each void is partly bound by a surface of each of the plurality of conducting layers which acts as an internal submicron electrode.
The number of internal submicron electrodes in each void may be one, two, three, four or five (or more). Such embodiments may be formed by successive lamination (eg deposition or growth) of the conducting layers and insulating capping layers. The dimensions and absolute spatial locations within the void and relative spatial locations of each of the internal submicron electrodes may be precisely defined enabling independent optimisation of the electroanalysis of multiple analytes.
Preferably the planar electrode further includes: a second conducting layer, wherein the first conducting layer is sandwiched to leave exposed only a first electrical contact region and the second conducting layer is sandwiched to leave exposed only a second electrical contact region, wherein the array of etched voids extends through the first conducting layer, the first insulating capping layer and the second conducting layer, wherein each void is partly bound by a surface of the first conducting layer which acts as an internal submicron electrode and/or by a surface of the second conducting layer which acts as an internal submicron electrode. The first conducting layer and second conducting layer may be substantially coplanar (eg laterally spaced apart). The first conducting layer and second conducting layer may be non-coplanar (eg axially spaced apart, preferably substantially co-axially spaced apart). This may require multilevel metal interconnect.
Preferably the planar electrode includes: a second conducting layer and a second insulating capping layer, wherein the first conducting layer is
sandwiched to leave exposed only a first electrical contact region and the second conducting layer is sandwiched to leave exposed only a second electrical contact region, wherein the array of etched voids extends through the first conducting layer, the first insulating capping layer, the second conducting layer and the second insulating capping layer, wherein each void is partly bound by a surface of the first conducting layer which acts as an internal submicron electrode and/or by a surface of the second conducting layer which acts as an internal submicron electrode. The first conducting layer and second conducting layer may be substantially coplanar (eg laterally spaced apart). The first conducting layer and second conducting layer may be non-coplanar (eg axially spaced apart, preferably substantially co-axially spaced apart). This may require multilevel metal interconnect.
Preferably the array of etched voids is a plurality of discrete sub-arrays of etched voids. The array (or each sub-array) may be a linear or staggered (eg herringbone) pattern. The array (or each sub-array) may be a cubic pattern. The array (or each sub-array) may be a multi-dimensional (eg bi-dimensional) array.
The array of voids may be mechanically or chemically etched according to the desired application. Each void may be an aperture, through-hole, well, tube, capillary, pore, bore or trough. Preferably each etched void is a well. The well may terminate in an insulating capping layer or the insulating substrate layer. The well may terminate in a conducting layer which provides an internal submicron electrode in the base of the well. The (or each) conducting layer may increase in thickness away from the voids. Preferably the (or each) conducting layer is a substantially planar conducting layer.
The (or each) conducting layer may be metallic. The conducting layer may be composed of a noble metal such as platinum, gold or silver, a metal nitride (eg titanium nitride), carbon, graphite, graphene or a metal oxide. The (or each) conducting layer may be an ion exchange polymer. The (or each) conducting layer may be a functionalised (eg chemically or biologically functionalised) metal.
The (or each) insulating capping layer may be ceramic or polymeric (eg an ion exchange resin). For example, the (or each) insulating capping layer may be composed of silicon dioxide, silicon nitride or poly(ethylenetetraphthalate). The (or each) insulating capping layer may be reagent-loaded or functionalised to suit particular applications.
Typically the electrical contact region is an electrical contact lip. The electrical contact lip may be a peripheral contact edge such as a square contact edge of the conducting layer. The electrical contact lip may be a wide area electrical contact lip (eg the electrical contact lip may extend along substantially the entire length of the periphery of the planar electrode). The electrical contact lip may be substantially T-shaped.
The or each submicron electrode is typically partly or wholly annular.
The (or each) conducting layer may be substantially rectangular, T-shaped, serpentine or digitated. A serpentine or digitated conducting layer may usefully provide an array of voids with different combinations of internal submicron electrodes on the same level.
In a preferred embodiment, the first conducting layer is substantially
sandwiched by only the first insulating capping layer such as to leave exposed only an electrical contact lip of the first conducting layer, wherein the array of etched voids extends through only the first insulating capping layer and the first conducting layer.
In a preferred embodiment, the first conducting layer is fabricated on the insulating substrate layer and is substantially sandwiched by the first insulating capping layer and the insulating substrate layer such as to leave exposed only an electrical contact region of the first conducting layer. In a preferred embodiment, the planar electrode further comprises: a second insulating capping layer fabricated on the insulating substrate layer, wherein the first conducting layer is fabricated on the second insulating capping layer and is substantially sandwiched by the first insulating capping layer and the second insulating capping layer such as to leave exposed only an electrical contact region of the first conducting layer.
In an embodiment, the planar electrode further comprises: a second insulating capping layer, wherein the first conducting layer is fabricated on the second insulating capping layer and is substantially
sandwiched by the first insulating capping layer and the second insulating capping layer such as to leave exposed only an electrical contact region of the first conducting layer; a second conducting layer, wherein the second conducting layer is fabricated on the insulating substrate layer and is substantially sandwiched by the second insulating capping layer and the insulating substrate layer such as to leave exposed only an electrical contact region of the second conducting layer, wherein the array of etched voids extends through at least the first insulating capping layer, the first conducting layer and the second insulating capping layer, wherein each void is partly bound by a surface of the first conducting layer which acts as an internal submicron electrode.
Preferably the array of etched voids extends through only the first insulating capping layer, the first conducting layer and the second insulating capping layer.
Preferably the array of etched voids extends through the first insulating capping layer, the first conducting layer, the second insulating capping layer and the second conducting layer, wherein each void is partly bound by a surface of the first conducting layer which acts as a first internal submicron electrode and by a surface of the second conducting layer which acts as a second internal submicron electrode.
In an embodiment, the planar electrode further comprises: a second conducting layer, wherein the first conducting layer is digitated and the second conducting layer is digitated, wherein the first conducting layer and the second conducting layer are interdigitally fabricated on the insulating substrate layer and are substantially sandwiched by the first insulating capping layer and the insulating substrate layer such as to leave exposed only an electrical contact region of the first conducting layer and an electrical contact region of the second conducting layer, wherein the array of etched voids extends through the first insulating capping layer, the first conducting layer and the second conducting layer, wherein each void is partly bound by a surface of the first conducting layer which acts as a first internal submicron electrode and is partly bound by a surface of the second conducting layer which acts as a second internal submicron electrode.
In an embodiment, the planar electrode further comprises: a second conducting layer, wherein the second conducting layer is substantially coplanar with the first conducting layer, wherein each of the first conducting layer and the second conducting layer is capped by the first insulating capping layer and is
substantially sandwiched by at least the first insulating capping layer such as to leave exposed only an electrical contact region of the first conducting layer and an electrical contact region of the second conducting layer respectively, wherein one or more first etched voids extend through the first insulating capping layer and the first conducting layer and one or more second etched voids extend through the first insulating capping layer and the second conducting layer, wherein each first etched void is partly bound by a surface of the first
conducting layer which acts as an internal submicron electrode and each second etched void is partly bound by a surface of the second conducting layer which acts as an internal submicron electrode.
Preferably each of the first conducting layer and the second conducting layer is substantially sandwiched by only the first insulating capping layer such as to leave exposed only an electrical contact region of the first conducting layer and an electrical contact region of the second conducting layer respectively.
The insulating substrate layer is typically composed of silicon, silicon dioxide or a polymeric material (such as polyester or polyimide). Preferably the insulating substrate layer is composed of silicon.
In a preferred embodiment, the assembly further comprises an electrically conductive sleeve in electrical contact with the elongate probe and recessed holder, wherein the electrically conductive sleeve is electrically grounded. The electrically conductive sleeve advantageously reduces electromagnetic noise. Typically the electrically conductive sleeve substantially envelopes the elongate probe and recessed holder. Preferably the electrically conductive sleeve is an electrically conductive mesh sleeve. An electrically conductive mesh sleeve has the advantage of not hindering the access of the analyte to the radial entry port.
In a preferred embodiment, the assembly further comprises a manifold housed in the radial entry port, wherein the manifold is equipped with an injection port (eg a low or zero volume injection port) for delivering analyte and an outlet port. Preferably the manifold is dismountably housed in the radial entry port.
Preferably the injection port and outlet port are disposed so as to be
diametrically opposed in the radial entry port. This serves advantageously to ensure substantially uniform exposure of the electroanalytical interrogation region to the analyte.
Preferably the manifold rests on an apron of the planar gasket at the base of the radial entry port. This embodiment is useful for interrogating a very small volume of analyte.
Preferably the injection port and outlet port are connected to a flow system.
The manifold may include a reference electrode which contacts the analyte opposite the electroanalytical interrogation region.
The manifold may be secured in the radial entry port using fasteners such as bolts or by a brace which surrounds the elongate probe.
In a preferred embodiment, the assembly further comprises a temperature controller for controlling the temperature of the planar electrode, wherein the temperature controller is in intimate thermal contact with a surface of the recessed holder.
The temperature controller may include a thermally conductive saddle in intimate thermal contact with a surface of the recessed holder, a temperature probe (eg a thermistor or Pt 100 sensor) inserted in the thermally conductive saddle and an active temperature device (eg a simple heater, a Peltier or a thermoelectric cooler) mounted on the thermally conductive saddle. The thermally conductive saddle may be composed of a material which is a good thermal conductor (eg stainless steel). The temperature controller may be insulated using (for example) a closed cell polymer such as Polyfoam™.
δ The exhaust of the active temperature device may be vented or actively cooled/heated by (for example) a fan to provide highly precise temperature control.
The thermally conductive saddle may be positioned alongside the manifold.
In a preferred embodiment, the assembly is adapted to restrain the recessed holder in the radial socket. The recessed holder may be restrained in the radial socket with a constant force sufficient to assist the planar gasket to provide the analyte with discrete access to the electroanalytical interrogation region and to provide the electrical connector with discrete access to the electrical contact region.
For example, the recessed holder may be fastened to the floor of the radial socket. For example, the recessed holder may be restrained in the radial socket by a snap-fit or clip-close arrangement.
Typically the planar gasket is composed of Teflon, PTFE, Viton, silicone or nitrile rubber.
The present invention will now be described in a non-limitative sense with reference to the accompanying Figures in which:
Figure 1 shows a plan view of a planar electrode of a first embodiment of the assembly of the invention;
Figures 2 and 3 show a side elevation, plan view, end elevation and perspective view of a recessed holder of the first embodiment of the assembly of the invention;
Figure 4 shows a plan view and side elevation of the planar electrode mounted in the recessed holder;
Figure 5 shows a plan view of a planar gasket of the first embodiment of the assembly of the invention;
Figure 6 shows a plan view and side elevation of the position of the planar gasket when the planar electrode is mounted in the recessed holder;
Figure 7 shows an elongate probe of the first embodiment of the assembly of the invention; Figure 8 shows a side elevation of the first embodiment of the assembly of the invention;
Figure 9 shows an end elevation of the first embodiment of the assembly of the invention;
Figure 10 shows a side elevation of a second embodiment of the assembly of the invention which includes a manifold;
Figure 11 shows an end elevation of the second embodiment of the assembly of the invention;
Figure 12 shows a plan view of the manifold of the second embodiment of the assembly of the invention;
Figure 13 shows a side elevation of a third embodiment of the assembly of the invention which includes a temperature controller; and
Figure 14 shows an end elevation of the third embodiment of the assembly of the invention.
Figure 1 shows a plan view of a planar electrode 1 of a first embodiment of the assembly of the invention. The planar electrode 1 has a laminate structure with a silicon substrate layer, a lOOOnm silicon dioxide insulating capping layer, a 50 nm platinum conducting layer and a 500 nm silicon nitride insulating capping layer. The planar electrode 1 is configured to expose only an electrical contact lip 2 and to discriminate an electroanalytical interrogation region 3 of the conducting layer. The electroanalytical interrogation region 3 is an array of wells formed by etching through the silicon nitride insulating capping layer, the platinum conducting layer and 500 nm into the silicon dioxide insulating capping layer.
Figures 2 and 3 show a recessed holder 21 of the first embodiment of the assembly of the invention. The recessed holder 21 is semi-cylindrical and has a planar mounting face 26. The mounting face 26 has a recess 22 in which the planar electrode 1 is recess mountable. The planar electrode 1 is shown recess mounted in the recess 22 of the recessed holder 21 in Figure 4. A packing shim 41 is placed in the recess 22 to ensure that the planar electrode 1 is flush with the mounting face 26. In other embodiments, the planar electrode 1 may be flush with the mounting face 26 without the need for a packing shim. Four positioning lugs 25 in the mounting face 26 and a guide tongue 23 on each end face 29 ensure precise positioning of the recessed holder 21 during assembly as described below. A pair of holes 27 enables the recessed holder 21 to be held in place during assembly. Two pairs of counterbore holes 24 receive retaining screws (not shown) to secure the assembly with a constant force between the recessed holder 21 and the elongate probe.
Figure 5 shows a plan view of a planar gasket 50 of the first embodiment of the assembly of the invention. A large aperture 51 provides discrete access to the electroanalytical interrogation region 3. A small aperture 52 provides discrete access to the electrical contact lip 2. Cut away portions 53 accommodate the positioning lugs 25 in the mounting face 26 of the recessed holder 21. Four apertures 55 allow the retaining screws to pass through. Figure 6 shows the position of the planar gasket 50 when the planar electrode 1 is recess mounted in the recessed holder 21.
Figure 7 shows an elongate probe 70 of the first embodiment of the assembly of the invention. The elongate probe 70 is substantially cylindrical and is equipped with a semi-cylindrical socket 71 in which is radially insertable the recessed holder 21. The elongate probe 70 includes an axial stepped bore 72. A floor 73 of the semi-cylindrical socket 71 includes a radial entry port 74 and a chamber 75 spaced apart from the radial entry port 74. The chamber 75 is accessible from the axial stepped bore 72. A pair of grooves 77 serves to accommodate the guide tongues 23 of the recessed holder 21. Four apertures 700 receive the retaining screws.
In Figure 7, an electrical connector 79 is shown mounted in the chamber 75 substantially flush with the floor 73 with the exception of a pair of protuberant connector pins 78. The protuberant connector pins 78 make electrical contact with the electrical contact lip 2 of the planar electrode 1. The electrical connector 79 is connected to electrical signal wire in one or more lead-out cables (not shown) before the electrical connector 79 is mounted in the chamber 75. The lead-out cables extend through the axial stepped bore 72 optionally through a cable gland and are terminated in a BNC jack plug connector to make connection to electroanalytical instrumentation such as a potentiostat.
Figures 8 and 9 show side and end elevations of the first embodiment of the assembly of the invention 80 respectively. The assembly 80 is assembled by inserting the recessed holder 21 radially into the semi-cylindrical socket 71 of the elongate probe 70. The walls of the recessed holder 21 are a tight-fit to the walls of the semi-cylindrical socket 71 to withstand deformation during assembly or tightening of the retaining screws. The planar gasket 50 is sandwiched between the recessed holder 21 and elongate probe 70. The large aperture 51 in the planar gasket 50 provides analyte A fed into the radial entry port 74 with discrete access to the electroanalytical interrogation region 3. The small aperture 52 in the planar gasket 50 provides the protuberant connector pins 78 of the electrical connector 79 with discrete access to the electrical contact region 2 to effect electrical connection with the planar electrode 1.
In the first embodiment of the assembly 80, the planar electrode 1 may be interrogated when the electroanalytical interrogation region 3 has been discretely accessed by the analyte A. This may be achieved by immersing the assembly 80 in the analyte A up to and beyond the radial entry port 74 (eg by vertical dipping) or by holding the assembly 80 horizontally and dropping analyte A into the radial entry port 74 which acts as a well. The analyte A should cover the entirety of the electroanalytical interrogation region 3.
Figures 10 and 11 show a second embodiment of the assembly of the invention 100. The assembly 100 is identical to the assembly of the first embodiment 80 but additionally includes a manifold 101 housed in the radial entry port 74. The manifold 101 is equipped with an injection port 102 for delivering analyte A and an outlet port 103. In this embodiment, the injection port 102 and the outlet port 103 are disposed so as to be diametrically opposed in the radial entry port 74. The manifold 101 rests on an apron 105 of the planar gasket 50 at the base of the radial entry port 74 which makes it useful for interrogating a very small volume of analyte A (see Figure 12).
Figures 13 and 14 show a third embodiment of the assembly of the invention 120. The assembly 120 is identical to the assembly of the first embodiment 80 but additionally includes a temperature controller. The temperature controller comprises a thermally conductive saddle 135, a temperature probe 131 mounted in the thermally conductive saddle 135 and an active temperature device 130 mounted on the thermally conductive saddle 135. The temperature probe 131 communicates with the input side 132 of a drive controller 133 which
communicates with the active temperature device 130.
The thermally conductive saddle 135 is fastened to the elongate probe 70 using screws or bolts or a brace which extends around the elongate probe 70. The temperature probe 131 may be a thermistor or PtlOO sensor and the active temperature device 130 is a simple heater, a Peltier or a thermoelectric cooler. The exhaust side (the underside in Figure 13) when using a Peltier or thermoelectric cooler should be cooled either passively through convection or actively using a fan.

Claims

1. An assembly for electroanalysis of an analyte comprising: a planar electrode which includes a conducting layer and an insulating substrate layer, wherein the planar electrode is configured to discriminate an electrical contact region of the conducting layer and an electroanalytical interrogation region of the conducting layer; a recessed holder in which the planar electrode is recess mounted flushly whereby to facilitate access to the electrical contact region and the
electroanalytical interrogation region; an elongate probe including a radial socket in which is inserted radially the recessed holder and an axial bore, wherein a floor of the radial socket includes a radial entry port for the analyte and a chamber spaced apart from the radial entry port and in communication with the axial bore; an electrical connector mounted in the chamber substantially flush with the floor, wherein the electrical connector is connectable to an electrical signal carrier extending through the axial bore; and a planar gasket sandwiched between the recessed holder and the floor of the radial socket, wherein the planar gasket is apertured to provide the analyte with discrete access to the electroanalytical interrogation region and to provide the electrical connector with discrete access to the electrical contact region.
2. An assembly as claimed in claim 1 wherein the electrical contact region is an electrical contact lip.
3. An assembly as claimed in claim 1 or 2 wherein the planar electrode has a laminate structure and further includes a first insulating capping layer, wherein the conducting layer is a first conducting layer capped by the first insulating capping layer and substantially sandwiched by at least the first insulating capping layer such as to leave exposed only the electrical contact region of the first conducting layer and wherein the electroanalytical interrogation region is an array of etched voids extending through at least the first insulating capping layer and the first conducting layer, wherein each void is partly bound by a surface of the first conducting layer which acts as an internal submicron electrode.
4. An assembly as claimed in claim 3 wherein the planar electrode further comprises: a second insulating capping layer fabricated on the insulating substrate layer, wherein the first conducting layer is fabricated on the second insulating capping layer and is substantially sandwiched by the first insulating capping layer and the second insulating capping layer such as to leave exposed only an electrical contact region of the first conducting layer.
5. An assembly as claimed in any preceding claim wherein the insulating substrate layer is composed of silicon.
6. An assembly as claimed in any preceding claim further comprising an electrically conductive sleeve in electrical contact with the elongate probe and recessed holder, wherein the electrically conductive sleeve is electrically grounded.
7. An assembly as claimed in claim 6 wherein the electrically conductive sleeve is an electrically conductive mesh sleeve.
8. An assembly as claimed in any preceding claim further comprising a manifold housed in the radial entry port, wherein the manifold is equipped with an injection port for delivering analyte and an outlet port.
9. An assembly as claimed in claim 8 wherein the injection port and outlet port are disposed so as to be diametrically opposed in the radial entry port.
10. An assembly as claimed in claim 8 or 9 wherein the manifold rests on an apron of the planar gasket at the base of the radial entry port.
11. An assembly as claimed in claim 8, 9 or 10 wherein the injection port and outlet port are connected to a flow system.
12. An assembly as claimed in any of claims 8 to 11 wherein the manifold includes a reference electrode.
13. An assembly as claimed in any preceding claim further comprising a temperature controller for controlling the temperature of the planar electrode, wherein the temperature controller is in intimate thermal contact with a surface of the recessed holder.
14. An assembly as claimed in claim 13 wherein the temperature controller includes a thermally conductive saddle in intimate thermal contact with a surface of the recessed holder, a temperature probe inserted in the thermally conductive saddle and an active temperature device mounted on the thermally conductive saddle.
15. An assembly as claimed in any preceding claim wherein the elongate probe is substantially cylindrical and the radial socket is a semi-cylindrical socket.
PCT/GB2013/051006 2012-04-27 2013-04-22 Assembly for electroanalysis of an analyte WO2013160662A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB201207384A GB201207384D0 (en) 2012-04-27 2012-04-27 Assembly
GB1207384.7 2012-04-27

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WO (1) WO2013160662A1 (en)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0394990A2 (en) * 1989-04-27 1990-10-31 Kyoto Daiichi Kagaku Co., Ltd. Dry-operative ion-selective electrode
US20010050228A1 (en) * 2000-06-07 2001-12-13 Gerard Jaeger Electrochemical sensor with increased reproducibility
EP2169391A1 (en) * 2008-09-30 2010-03-31 ibidi GmbH Sample chamber and device for mounting said chamber

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0394990A2 (en) * 1989-04-27 1990-10-31 Kyoto Daiichi Kagaku Co., Ltd. Dry-operative ion-selective electrode
US20010050228A1 (en) * 2000-06-07 2001-12-13 Gerard Jaeger Electrochemical sensor with increased reproducibility
EP2169391A1 (en) * 2008-09-30 2010-03-31 ibidi GmbH Sample chamber and device for mounting said chamber

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