IMPROVEMENTS IN THE ARSINE ACCUMULATION HELIUM GLOW DETECTOR PROCEDURE FOR DETERMINING TRACES OF ARSENIC

The convenience and reproducibility of this analytical procedure have been improved and the time required reduced to 6 minutes per sample, by changing several elements of the procedure. The sample solution is more heavily buffered, gas leakage is prevented and liquid aerosol is eliminated from the gas stream with an impinger without losing AsH3. The cold trap Is warmed up by a uniform stream of high-velocity air; the newly designed glow chamber prevents coating of the observation window, while giving a detection limit of ≲0.1 ng As. The addition of 1 mg ascorbic acid/mL to As solutions prevents spontaneous oxidation of As3+ at the 1-1000 ppb level at room temperature without reducing any Ass+. A procedure Is given for eliminating the As3+ blank contributed by the buffer solution. © 1979, American Chemical Society. All rights reserved.