Determination of monomethylarsenous acid by hydride generation – gas phase molecular absorption spectrometry Original Research Article

This paper presents a method for the determination of methylarsenous acid which is converted into gaseous methylarsine by adding a sodium tetrahydroborate(III) solution. The generated arsine is collected in a liquid nitrogen cryogenic trap. This is revolatilized and driven to the quartz flow cell and measured by gas phase molecular absorption spectrometry with diode array detection. The spectra obtained over a wide range of wavelengths allows multivariate calibration. The parameters affecting the production and collection of the arsines are studied. The detection limit, (6 × SD of blank) = 2.8 ng ml−1 and the relative standard deviation (n = 10) at 28 ng ml−1 was 5.3%. An interference study is made.