Solid-state detector for gas-phase flow injection of nitrogen dioxide at ambient temperature

Abstract

An Au-RbAg₄l₅-Ag galvanic detector, consisting of a disc 13 mm in diameter and 1.3 mm thick has been developed by using a rubidium silver iodide solid electrolyte. The working electrode (25 nm thick) was made by sputtering gold in an argon atmosphere. When the sample (10 ml) containing NO₂ was injected into the nitrogen carrier stream flowing at a rate of 45 ml min^–1, the current flowing in the external circuit was linearly related to the concentration of NO₂ in the range 10 p.p.b.–1 p.p.m. Twelve samples could be analysed per hour. After 200 samples (50 p.p.b. of NO₂-N₂, 10 ml) had been analysed, the response decreased by about 10% of its original value.