Amperometric biosensor for formic acid in air

Abstract

The possibility of developing a simple, inexpensive and specific personal passive "real-time" air sampler based on biosensor technology was investigated. Formic acid was used as a model substance. The sensor is based on the enzymatic reaction between formic acid and formate dehydrogenase with NAD + as a cofactor and Meldola's blue as mediator. An effective way to immobilise the enzyme, cofactor and Meldola's blue on screen-printed electrodes was found to be in a mixture of glycerol and phosphate buffer covered with a gas-permeable membrane. When the sensor was introduced into an atmosphere containing formic acid, it gave a distinct and rapid amperometric response.

Direct electrochemistry and Os-polymer-mediated bioelectrocatalysis of NADH oxidation by Escherichia coli flavohemoglobin at graphiteelectrodes

“…To overcome these problems modified electrodes were extensively used to reduce the overpotential of the reaction and to maintain fast reaction kinetics. Modified electrodes for NADH oxidation exploit conductive polymers and different types of mediators such as quinones, diimines, flavins, phenothiazines and phenoxazine derivatives, also polymerized (Bartlett and Simon, 2003;Bartlett et al, 1991;Gorton, 1986;Gorton andDominguez, 2002, 2007;Rincon et al, 2010;Sandström et al, 2000). Another approach involves bioelectrocatalytic oxidation of NADH, however, in practice just a few flavoenzymes were successfully applied for direct (unmediated) NADH oxidation (Barker et al, 2007;Kobayashi et al, 1992;Reeve et al, 2012;Zu et al, 2003); otherwise, enzyme wiring to electrodes by a suitable redox mediator was used (Antiochia and Gorton, 2007;Tasca et al, 2008;Tsujimura et al, 2002a).…”

Gas Diffusion Electrodes for Use in an Amperometric Enzyme Biosensor

“…Park et al presented a sensor for ethanol [16] based on a screen-printed three-electrode strip. Saini et al described a sensor for phenol [17] based on an interdigitated array of microband electrodes, and Sandstrçm et al a sensor for formic acid in air [18] based on a screen-printed threeelectrode configuration. In general, sensors using a planar electrode configuration are designed for single use only or as sniffers, or have a short lifetime due to deterioration of the thin enzyme/electrolyte layer, where reaction products accumulate, or which is subject to dehydration.…”

An assessment of sensing technologies for the detection of clandestine methamphetamine drug laboratories

“…Common examples include chemical resistors (typically referred to as chemiresistors) [22][23][24][25][26][27][28][29], chemically sensitive field-effect transistors (chemFETs) [30,31], electrochemical sensors [32][33][34][35][36][37][38][39][40][41][42], semiconducting metal oxide (SMO) sensors [43][44][45][46][47][48][49], and thermal sensors [50][51][52][53][54]. The detection mechanism varies across this class of sensors from a swelling-induced change in the conductance of polymer-based chemiresistors, to the calorimetricinduced change in conductance of thermal sensors.…”