[go: up one dir, main page]

GB2480719A - Electrochemical gas sensor for detecting prussic acid - Google Patents

Electrochemical gas sensor for detecting prussic acid Download PDF

Info

Publication number
GB2480719A
GB2480719A GB1101060A GB201101060A GB2480719A GB 2480719 A GB2480719 A GB 2480719A GB 1101060 A GB1101060 A GB 1101060A GB 201101060 A GB201101060 A GB 201101060A GB 2480719 A GB2480719 A GB 2480719A
Authority
GB
United Kingdom
Prior art keywords
gas sensor
electrochemical gas
carbon nanotubes
electrode
electrolyte
Prior art date
Legal status (The legal status 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 status listed.)
Granted
Application number
GB1101060A
Other versions
GB201101060D0 (en
GB2480719B (en
Inventor
Frank Mett
Sabrina Sommer
Kerstin Lichtenfeldt
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Draeger Safety AG and Co KGaA
Original Assignee
Draeger Safety AG and Co KGaA
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
Priority claimed from DE102010021975.4A external-priority patent/DE102010021975B4/en
Application filed by Draeger Safety AG and Co KGaA filed Critical Draeger Safety AG and Co KGaA
Priority to GB1101060.0A priority Critical patent/GB2480719B/en
Publication of GB201101060D0 publication Critical patent/GB201101060D0/en
Publication of GB2480719A publication Critical patent/GB2480719A/en
Application granted granted Critical
Publication of GB2480719B publication Critical patent/GB2480719B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B82NANOTECHNOLOGY
    • B82YSPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y15/00Nanotechnology for interacting, sensing or actuating, e.g. quantum dots as markers in protein assays or molecular motors
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/26Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
    • G01N27/28Electrolytic cell components
    • G01N27/30Electrodes, e.g. test electrodes; Half-cells
    • G01N27/308Electrodes, e.g. test electrodes; Half-cells at least partially made of carbon
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/26Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
    • G01N27/403Cells and electrode assemblies
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/26Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
    • G01N27/403Cells and electrode assemblies
    • G01N27/404Cells with anode, cathode and cell electrolyte on the same side of a permeable membrane which separates them from the sample fluid, e.g. Clark-type oxygen sensors
    • G01N27/4045Cells with anode, cathode and cell electrolyte on the same side of a permeable membrane which separates them from the sample fluid, e.g. Clark-type oxygen sensors for gases other than oxygen
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/26Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
    • G01N27/403Cells and electrode assemblies
    • G01N27/406Cells and probes with solid electrolytes
    • G01N27/407Cells and probes with solid electrolytes for investigating or analysing gases
    • G01N27/4073Composition or fabrication of the solid electrolyte
    • G01N27/4074Composition or fabrication of the solid electrolyte for detection of gases other than oxygen
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N33/00Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
    • G01N33/0004Gaseous mixtures, e.g. polluted air
    • G01N33/0009General constructional details of gas analysers, e.g. portable test equipment
    • G01N33/0027General constructional details of gas analysers, e.g. portable test equipment concerning the detector
    • G01N33/0036General constructional details of gas analysers, e.g. portable test equipment concerning the detector specially adapted to detect a particular component

Landscapes

  • Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • General Health & Medical Sciences (AREA)
  • Molecular Biology (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Physics & Mathematics (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Physics & Mathematics (AREA)
  • Electrochemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Nanotechnology (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Combustion & Propulsion (AREA)
  • Food Science & Technology (AREA)
  • Medicinal Chemistry (AREA)
  • Measuring Oxygen Concentration In Cells (AREA)

Abstract

An electrochemical gas sensor 1 for the detection of prussic acid (HCN) in a gas sample comprises a housing 2, measuring electrode 3 of carbon nanotubes (CNT) and a counter-electrode 8 in an electrolyte 9, which comprises lithium bromide (LiBr) in aqueous solution. Electrodes 3, 8 and reference electrode 6 are connected to potentiostat 16 which measures the potential at measuring electrode 3.

Description

Electrochemical gas sensor for, and method of, detecting prussic acid The invention relates to an electrochemical gas sensor for, and a method of, detecting prussic acid.
A gas sensor for determining 502 or H2S, which contains a measuring electrode comprising carbon nanotubes, is known from DE 10 2006 014 713 B3. The electrolyte contains a mediator compound based on transition metal salts with which a selective determination of the desired gas component is possible.
Mediator compounds are compounds which comprise, apart from at least one acid group, at least one further group selected from hydroxy and acid groups. In particular, the mediator compound is a carboxylic acid salt which comprises, apart from the one carboxylic acid group, at least one hydroxy group, preferably at least two hydroxy groups, and/or at least one further carboxylic acid group. Suitable compounds are also tetraborates, such as sodium tetraborate or lithium tetraborate. Transition metal salts, in particular Cu salts of such mediators, permit a selective determination of SO2.
A measuring device described in US 2005/0230 270 Al contains a microelectrode arrangement of carbon nanotubes for detecting substances in liquid or gaseous samples.
An electrochemical gas sensor is known from DE 199 39 011 Cl, the measuring electrode whereof is made from diamond-like carbon. An aqueous lithium bromide, which at the same time acts as a mediator, is used as the electrolyte. The mediator function is based here on the oxidation of lithium bromide to form bromine through the chlorine gas to be measured. The potential at the measuring electrode is adjusted such that bromine is reduced at the measuring electrode.
The present invention seeks to provide an electrochemical gas sensor for, and a method of, detecting a prussic acid.
The present invention, in a first aspect, is an electrochemical gas sensor for the detection of prussic acid in a gas sample which comprising a measuring electrode containing carbon nanotubes (CNT) and a counter-electrode in an electrolyte solution comprising lithium bromide.
The present invention, in a second aspect, is a method for the detection of prussic acid with an electrochemical gas sensor which comprises a measuring electrode of carbon nanotubes (CNT) and an aqueous LiBr solution as an electrolyte, in which the potential at the measuring electrode is adjusted in such a way that dissolved bromine is present in the electrolyte for the detection reaction.
The present invention, in a second aspect, is the use of an electrochemical gas sensor comprising a measuring electrode of carbon nanotubes (CNT) and a counter-electrode in an electrolyte, which contains lithium bromide, for the detection of prussic acid.
Embodiments of the invention will now be described, by way of example only, with reference to the accompanying figure 1 which is a schematic cross-sectional view of a gas sensor according to the present invention.
Surprisingly, it has been shown that prussic acid can be detected with a high degree of sensitivity using a measuring electrode comprising carbon nanotubes (CNT) in combination with an aqueous electrolyte containing lithium bromide, wherein the temperature and humidity changes have only a subordinate effect on the measurement signal. Although it is already known to use an electrode made from diamond-like carbon in combination with an aqueous electrolyte of lithium bromide, it has surprisingly emerged that prussic acid can be detected solely in combination with a measuring electrode of carbon nanotubes (CNT). The potential at the measuring electrode must be adjusted for the detection reaction in such a way that bromine is present freely dissolved in the electrolyte through oxidation of the lithium bromide. The operating point has to be set such that a sensor base current as low as possible is present Measuring electrodes produced from carbon nanotubes (CNT) are long-term stable and easy to integrate into existing sensor designs. Carbon nanotubes have a structural affinity with the fullerenes, which can be produced for example by evaporation of carbon by a laser evaporation process. A single-wall carbon nanotube has, for example, a diameter of one nanometre and a length of approximately a thousand nanometres. Apart from single-wall carbon nanotubes, double-wall carbon nanotubes (DW CNT) and structures with multiple walls (MW CNT) are also known.
In the case of measuring electrodes comprising carbon nanotubes (CNT), the layer thickness of the electrode material in the finished electrode lies in a range between 0.5 microns and 500 microns, preferably 10 to 50 microns.
Multi-wall carbon nanotubes (MW CNT) in particular produce a particularly high measurement signal and are a particularly preferred embodiment.
For production-related reasons, carbon nanotubes are provided with metal atoms, e.g. Fe, Ni, Co including their oxides, so that such carbon nanotubes on measuring electrodes possess catalytic activities. It has proved to be advantageous to remove these metal particles by acid treatment.
The carbon nanotubes are expediently deposited on a porous carrier, a non-woven fabric material or a diffusion membrane. The carbon nanotubes are joined together in self-aggregation or with a binder. PTFE powder can expediently be used as a binder.
It is particularly advantageous to produce the carbon nanotubes from a prefabricated film, a so-called bucky paper. The measuring electrode can then be stamped directly out of the bucky paper. Large piece numbers can thus be produced cost effectively.
The measuring cell comprises openings which are provided with a membrane permeable to the analytes and otherwise close the measuring cell to the exterior. The electrochemical cell contains at least one measuring electrode and a counter-electrode, which can be disposed coplanar, plane-parallel or radially with respect to one another and which are each formed in a two-dimensionally extending manner. A reference electrode can also be present in addition to the counter-electrode.
Located between the plane-parallel electrodes is a separator, which holds the electrodes at a distance from one another and which is saturated with the electrolyte.
As electrode materials in the case of the reference electrode, use may be made of precious metals such as platinum or iridium, carbon nanotubes or an electrode of a 2' kind, which is made from a metal which is in equilibrium with a sparingly soluble metal salt.
The counter-electrode is expediently made from a precious metal, e.g. gold, platinum, iridium, or carbon nanotubes.
Hygroscopic alkali or alkaline-earth metal halides, preferably bromides, in aqueous solution are preferably used as conductive electrolytes. The pH value of the electrolyte is preferably stabilised with a buffer. Particularly advantageous formulations are an aqueous LiBr solution or an aqueous LiBr solution with saturated calcium carbonate CaCO3 as a solid phase at the bottom.
Calcium carbonate serves as a pH stabiliser for the electrolyte solution. As an alternative to calcium carbonate, other alkaline-earth carbonates are also suitable as pH stabilisers, such as magnesium carbonate or barium carbonate, which are expressly also included in the scope of protection.
An advantageous use of an electrochemical gas sensor comprising a measuring electrode of carbon nanotubes (CNT) and a counter-electrode in an electrolyte, which contains lithium bromide, consists in the detection of prussic acid in a gas sample. Multi-wall carbon nanotubes (MW CNT) are a preferred material for the measuring electrode. Particularly preferred electrolytes are an aqueous LiBr solution or an aqueous LiBr solution with saturated CaCO3 as a solid phase at the bottom.
A method according to the invention for the detection of prussic acid with an electrochemical gas sensor, which comprises a measuring electrode of carbon nanotubes (CNT) and an aqueous LiBr solution as an electrolyte, consists in the fact that the potential at the measuring electrode is adjusted in such a way that dissolved bromine is present in the electrolyte for the detection reaction.
Referring particularly to figure 1, a gas sensor 1 is shown, wherein there are arranged in sensor housing 2 a measuring electrode 3 of carbon nanotubes (CNT), on a diffusion membrane 4, a reference electrode 6 in a core 7 and a counter-electrode 8. The interior of sensor housing 2 is filled with an electrolyte 9 comprising an aqueous LiBr solution, wherein a pH stabiliser of calcium carbonate is additionally present as a solid phase at the bottom 10. Electrodes 3, 6, 8 are held at a fixed distance from one another by means of liquid-permeable non-woven fabrics 11, 12, 13. The gas admission takes place through an opening 15 in sensor housing 2. Gas sensor 1 is connected in a known manner to a potentiostat 16 with which the potential at measuring electrode 3 and also the operating point for the sensor base current are set.

Claims (17)

  1. Claims 1. An electrochemical gas sensor for the detection of prussic acid in a gas sample, comprising a measuring electrode containing carbon nanotubes (CNT) and a counter-electrode in an electrolyte solution comprising lithium bromide.
  2. 2. The electrochemical gas sensor according to claim 1, in which the carbon nanotubes are located on a porous carrier, a non-woven fabric material or a diffusion membrane.
  3. 3. The electrochemical gas sensor according to any one of claims 1 or 2, in which the nanotubes are joined together by self-aggregation or with the aid of a binder.
  4. 4. The electrochemical gas sensor according to claim 3, in which the binder is PTFE.
  5. 5. The electrochemical gas sensor according to any one of claims ito 4, in which the carbon nanotubes are present as a film in the form of a so-called bucky paper.
  6. 6. The electrochemical gas sensor according to any one of claims ito 5, in which the carbon nanotubes are present in the form of single-wall or multi-wall carbon nanotubes (MW CNT) with a layer thickness of the finished electrode material between 0.5 microns and 500 microns, preferably 10 to 50 microns.
  7. 7. The electrochemical gas sensor according to any one of claims 1 to 6, in which the counter-electrode is made of a precious metal, e.g. gold, platinum, iridium or carbon nanotubes.
  8. 8. The electrochemical gas sensor according to any one of claims 1 to 7, further including a reference electrode which is made of a precious metal, carbon nanotubes or an electrode of a second kind, the electrode of the second kind being a metal which is in equilibrium with a sparingly soluble metal salt.
  9. 9. The electrochemical gas sensor according to any one of claims 1 to 8, in which the electrolyte is present as an aqueous electrolyte.
  10. 10. The electrochemical gas sensor according to any one of claims 1 to 9, in which the electrolyte is an aqueous LiBr solution or an aqueous LiBr solution with saturated CaCO3 as a solid phase at the bottom.
  11. 11. A method for the detection of prussic acid with an electrochemical gas sensor which comprises a measuring electrode of carbon nanotubes (CNT) and an aqueous LiBr solution as an electrolyte, in which the potential at the measuring electrode is adjusted in such a way that dissolved bromine is present in the electrolyte for the detection reaction.
  12. 12. Use of an electrochemical gas sensor comprising a measuring electrode of carbon nanotubes (CNT) and a counter-electrode in an electrolyte, which contains lithium bromide, for the detection of prussic acid.
  13. 13. The use according to claim 12, in which the carbon nanotubes are present as multi-wall carbon nanotubes (MW CNT).
  14. 14. The use according to claim 12 or 13, in which an aqueous LiBr solution or an aqueous LiBr solution with saturated CaCO3 as a solid phase at the bottom (10) is present as an electrolyte (9).
  15. 15. An electrochemical gas sensor for the detection of prussic acid in a gas sample substantially as hereinbefore described with reference to, and/or as shown in, the accompanying figure.
  16. 16. A method for the detection of prussic acid with an electrochemical gas sensor substantially as hereinbefore described with reference the accompanying figure.
  17. 17. The use of an electrochemical gas sensor for the detection of prussic acid in a gas sample substantially as hereinbefore described with reference to the accompanying figure
GB1101060.0A 2010-05-28 2011-01-21 Electrochemical gas sensor for, and method of, detecting prussic acid Active GB2480719B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB1101060.0A GB2480719B (en) 2010-05-28 2011-01-21 Electrochemical gas sensor for, and method of, detecting prussic acid

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102010021975.4A DE102010021975B4 (en) 2010-05-28 2010-05-28 Electrochemical gas sensor and use of an electrochemical gas sensor for the detection of hydrocyanic acid
GB1101060.0A GB2480719B (en) 2010-05-28 2011-01-21 Electrochemical gas sensor for, and method of, detecting prussic acid

Publications (3)

Publication Number Publication Date
GB201101060D0 GB201101060D0 (en) 2011-03-09
GB2480719A true GB2480719A (en) 2011-11-30
GB2480719B GB2480719B (en) 2012-10-24

Family

ID=43769410

Family Applications (1)

Application Number Title Priority Date Filing Date
GB1101060.0A Active GB2480719B (en) 2010-05-28 2011-01-21 Electrochemical gas sensor for, and method of, detecting prussic acid

Country Status (1)

Country Link
GB (1) GB2480719B (en)

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2292805A (en) * 1994-08-26 1996-03-06 Mil Ram Techn Inc Electrochemical cell for detecting toxic gas
GB2353363A (en) * 1999-08-17 2001-02-21 Draegerwerk Ag Electrochemical gas sensor with diamond-like carbon measuring electrode
WO2005034204A2 (en) * 2003-09-30 2005-04-14 Nano-Proprietary, Inc. Nanobiosensor and carbon nanotube thin film transistors
EP1706130A2 (en) * 2003-12-15 2006-10-04 Nano-Proprietary, Inc. Matrix array nanobiosensor
GB2436695A (en) * 2006-03-30 2007-10-03 Draegerwerk Ag Electrochemical gas sensor with measuring electrode containing carbon nanotubes
GB2444136A (en) * 2006-11-22 2008-05-28 Draegerwerk Ag Electrochemical gas sensor including electrical connecting conductors or housing connection-making links made from carbon nanotubes

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2292805A (en) * 1994-08-26 1996-03-06 Mil Ram Techn Inc Electrochemical cell for detecting toxic gas
GB2353363A (en) * 1999-08-17 2001-02-21 Draegerwerk Ag Electrochemical gas sensor with diamond-like carbon measuring electrode
WO2005034204A2 (en) * 2003-09-30 2005-04-14 Nano-Proprietary, Inc. Nanobiosensor and carbon nanotube thin film transistors
EP1706130A2 (en) * 2003-12-15 2006-10-04 Nano-Proprietary, Inc. Matrix array nanobiosensor
GB2436695A (en) * 2006-03-30 2007-10-03 Draegerwerk Ag Electrochemical gas sensor with measuring electrode containing carbon nanotubes
GB2444136A (en) * 2006-11-22 2008-05-28 Draegerwerk Ag Electrochemical gas sensor including electrical connecting conductors or housing connection-making links made from carbon nanotubes

Also Published As

Publication number Publication date
GB201101060D0 (en) 2011-03-09
GB2480719B (en) 2012-10-24

Similar Documents

Publication Publication Date Title
US20110290672A1 (en) Electrochemical gas sensor
US20110290671A1 (en) Electrochemical gas sensor
US8268161B2 (en) Electrochemical sensor having a mediator compound with a solid
US8187437B2 (en) Electrochemical gas sensor
Sukeri et al. A facile electrochemical approach to fabricate a nanoporous gold film electrode and its electrocatalytic activity towards dissolved oxygen reduction
Silvester Recent advances in the use of ionic liquids for electrochemical sensing
US7883611B2 (en) Electrochemical sensor having a mediator compound
US7704374B2 (en) Electrochemical gas sensor
US9347907B2 (en) Device for providing a means for internal calibration in an electrochemical sensor
Sun et al. Simultaneous determination of ascorbic acid, dopamine and uric acid at a nitrogen-doped carbon nanofiber modified electrode
Sadeghi et al. A highly sensitive and selective electrochemical sensor for determination of Cr (VI) in the presence of Cr (III) using modified multi-walled carbon nanotubes/quercetin screen-printed electrode
US20200158678A1 (en) Nanostructured graphene-modified graphite pencil electrode system for simultaneous detection of analytes
Pandey et al. Nanocomposite of Prussian blue based sensor for l-cysteine: Synergetic effect of nanostructured gold and palladium on electrocatalysis
CN112213368B (en) Potential microelectrode sensor with universality and preparation and application thereof
Dong et al. Dual functional rhodium oxide nanocorals enabled sensor for both non-enzymatic glucose and solid-state pH sensing
Zhang et al. A novel electrochemical sensor based on reduced graphene oxide–TiO2 nanocomposites with high selectivity for the determination of hydroxychloroquine
Zhang et al. Selective determination of dopamine, ascorbic acid and uric acid at SDS-MWCNTs modified glassy carbon electrode
Papavasileiou et al. Simultaneous determination of guanine and adenine in human saliva with graphite sparked screen-printed electrodes
Kim et al. Ion-selective electrode-based sensors from the macro-to the nanoscale
Zakaria et al. Novel design of non-enzymatic sensor for rapid monitoring of hydrogen peroxide in water matrix
Emami et al. Design of poly-l-methionine–gold nanocomposit/multi-walled carbon nanotube modified glassy carbon electrode for determination of amlodipine in human biological fluids
John et al. On-site detection of uric acid using a portable electrochemical device based on a screen-printed electrode modified with nickel ferrite
GB2480719A (en) Electrochemical gas sensor for detecting prussic acid
Pourbahram et al. Facile and in situ production of reduced graphene oxide nanosheets paste electrode via electrochemical exfoliation of carbon paste electrode for fabricating a VEGF165 tumor marker aptasensor
Kumar et al. Modified carbon-thread based miniaturized electrochemical platform for real time serotonin detection