A Sensitive Micro Conductometric Ethanol Sensor Based on an Alcohol Dehydrogenase-Gold Nanoparticle Chitosan Composite

In this paper, a microconductometric sensor has been designed, based on a chitosan composite including alcohol dehydrogenase—and its cofactor—and gold nanoparticles, and was calibrated by differential measurements in the headspace of aqueous solutions of ethanol. The role of gold nanoparticles (GNPs) was crucial in improving the analytical performance of the ethanol sensor in terms of response time, sensitivity, selectivity, and reproducibility. The response time was reduced to 10 s, compared to 21 s without GNPs. The sensitivity was 416 µS/cm (v/v%)−1 which is 11.3 times higher than without GNPs. The selectivity factor versus methanol was 8.3, three times higher than without GNPs. The relative standard deviation (RSD) obtained with the same sensor was 2%, whereas it was found to be 12% without GNPs. When the air from the operator’s mouth was analyzed just after rinsing with an antiseptic mouthwash, the ethanol content was very high (3.5 v/v%). The background level was reached only after rinsing with water

Development of a Chitosan/Nickel Phthalocyanine Composite based Conductometric Micro‐sensor for Methanol Detection

International audienceThin-film composite of chitosan/nickel phthalocyanine (NiPc) was electrochemically deposited on the fingers of interdigitated gold electrodes, applying chronoamperometric polymerization technique. The presence of crystallized NiPc in the chitosan was confirmed by EDX and FTIR analysis. Acetone, ethanol, and methanol gas-sensing properties of the films prepared at optimum conditions were studied at atmospheric temperature, through differential measurements at an optimized frequency of 10 kHz, using a lock-in amplifier. The conductometric sensor presents the highest sensitivity of 60.2 μS.cm−1(v/v) for methanol and 700 ppm as the limit of detection. For validation, the methanol content of a commercial rubbing alcohol was determined

A Highly Sensitive Impedimetric Metamitron Microsensor Based on All-Solid-State Membrane Using a New Ion-Pair Complex, [3,3′-Co(1,2-closo-C₂B₉H₁₁)₂]⁻[C₁₀H₁₁ON₄]⁺

An all-solid-state impedimetric microsensor based on impedimetric measurements for detecting the herbicide metamitron (MM) is reported in the present work. For this purpose, a novel metamitron ionophore has been prepared. It was based on the isolation of the metamitron monoprotonated form coupled to the metallocarborane anion, cobalt bis (dicarbollide), ([3,3′-Co(1,2-closo-C2B9H11)2]−) as an ion-pair complex of the type [3,3′-Co(1,2-closo-C2B9H11)2]−[C10H11ON4]+. Once the ion-pair complex was synthetized, it was incorporated to a PVC-type membrane including o-Nitrophenyloctylether (o-NPOE) as plasticizer. The membrane was then drop-cast on top of polypyrrole-modified gold working microelectrodes. A quick response of 30 s has been provided by the microsensor in the range of metamitron concentrations between 10−8 M and 10−4 M with a limit of detection of 10−8 M. Furthermore, it was highly selective toward metamitron, when compared to some possible interfering compounds as imazapic and carbetamide

A microconductometric ethanol sensor prepared through encapsulation of alcohol dehydrogenase in chitosan: application to the determination of alcoholic content in headspace above beverages

International audienceA conductometric transducer is proposed for the first time for the detection of ethanol vapor. This ethanol microsensor is prepared by encapsulation of alcohol dehydrogenase (ADH) in chitosan. Interdigitated electrodes fabricated by silicon technology were used. The electrodeposition of chitosan allows the addressing of the chitosan film on the microconductometric devices and to encapsulate ADH and nicotinamide adenine dinucleotide (NAD?), which was monitored by FTIR. The analytical performance of the ethanol microsensor was determined in gaseous methanol, ethanol, and acetone samples, collected from the headspace above aqueous solutions of known concentration. The response time (tRec) of the sensor varies from 7 to 21 s from lower concentrations to higher concentrations. The detection limit is 0.12v/v % in the gas phase, correspondingto 0.22 M in the liquid phase. The relative standard deviation for the same sensor is from 12% for lower concentrations to 2% for higher concentrations. The ethanol sensor presents 2.6 times lower sensitivity for methanol and 28.3 times lower sensitivity for acetone. A detection of ethanol in the headspace of a red wine sample lead to an alcohol content in good agreement with the value given by the producer

Solid State Gas Sensor Based on Polyaniline Doped with [3,3′-Co(1,2-C2B9H11)2]⁻¹ for Detection of Acetone: Diagnostic to Heart Failure Disease

Acetone in human breath has been regarded as the important disease marker of Heart failure (HF). Therefore, preliminary study has been carried out for the use chemical sensor based on Polyaniline doped with [3,3′-Co(1,2-C2B9H11)2]−1 anion (PANI/COSANE) for the detection and quantification of acetone in human breath. This chemical sensor was prepared by Galvano-statically growing a polymeric layer based on PANI/COSANE and PANI/Nitrate by electrochemical polymerization onto the two different interdigitated gold microelectrodes on a silicon chip surface using cyclic voltammetry. Measurement of change in conductance due to the presence of acetone in its vicinity at room temperature (20⁻25 °C) is performed in differential configuration mode using Lock-in amplifier. The developed acetone sensor has been calibrated under different acetone atmospheres using a Lock-in amplifier. This novel Acetone micro sensor showed good response, recovery, and stability for the detection of acetone in the range of 1 ppm⁻8 ppm

A silicon nitride ISFET-based immunosensor for Tumor Necrosis Factor-alpha detection in saliva. A promising tool for heart failure monitoring

International audienc

A silicon nitride ISFET-based immunosensor for Tumor Necrosis Factor-alpha detection in saliva. A promising tool for heart failure monitoring

International audienc