Pulsed amperometric detection of ethanol in breath by gold electrodes supported on ion exchange membranes (solid polymer electrolytes)

Abstract

A sensitive and fast-responding amperometric sensor for the determination of ethanol in breath which eliminates oxygen interferences is described. It consists of a porous gold working electrode (facing the sample) supported on one face of an ion-exchange membrane which serves as a solid polymer electrolyte (SPE). The other side of the membrane faces an internal electrolyte solution (1 M aqueous NaOH) containing the counter and reference electrodes. The fouling of the gold working electrode, due to the ethanol oxidation process, is overcome by continuously cleaning and reactivating its surface by applying a triple-pulse potential waveform. The performance of this sensor has been tested in a closed-loop flow apparatus fed with synthetic ethanol-vapor samples obtained by evaporating aqueous solutions with known ethanol contents. The sensor displays a high current sensitivity and a low background noise, so that a low detection limit (2 mu g L(-1), 1 ppm v./v.) is estimated for a signal-to-noise ratio of 3. The responses are characterized by both a good reproducibility and a linear dependence on the ethanol concentration over a fairly wide range (more than three orders of magnitude), as well as by a short response time (ca. 1 s). This fast response time arises from the lack of a gas-permeable membrane and direct gas contact to the triple interphase among the gaseous analyte, the porous working electrode and the solid polymer electrolyte. The absence of significant interfering effects and the possibility of adopting such a device for the detection of ethanol in fermentation processes are also discussed

Simultaneous Detection of Peracetic Acid and Hydrogen Peroxide by Amperometry at Pt and Au Electrodes

“…The voltammetric unit consisted of an EG&G PARC Model 273 potentiostat driven by an EG&G PARC Model 270 software installed on a Pentium II computer, while for pulse amperometric measurements the mentioned potentiostat was driven by a software once again installed on a Pentium II computer and written in BASIC language by an IBM Personal Computer BASIC Compiler version 2.0 which was described previously [26].…”

Characteristics of Solid-State Amperometric Oxygen Sensor Using Pt/C Film Hot-Pressed onto Nafion Membrane

“…Furthermore, some reports [9,10] revealed that the noble metal alloys-modified Nafion electrodes performance had even more sensitivity. The metalization methods reported previously in the literature can be classified as 1) mechanical processes [11,12], 2) electrochemical processes [13,14], 3) vacuum sputtering processes [15,16], and 4) chemical reduction processes [17,18]. The vacuum sputtering procedure permits formation of electrodes of various shapes on the SPE surface, but the electrodes are poorly mechanically stable and are destroyed by changes in the membrane dimensions due to test medium humidity variations [19,20].…”

Metrological parameters of sulphur dioxide amperometric sensor containing addition of aprotic solvents

“…The sensors for ozone, sulphur dioxide, hydrogen sulphide, vapours of ethanol, hydrogen, methane, nitrogen dioxide or nitrogen monoxide were built [9][10][11][12][13][14][15][16]. Most of the above mentioned amperometric sensors exhibit superior metrological parameters, especially dynamic properties and sensitivity, as compared to the sensors with porous, permeable membrane.…”