Xc. Le et al., A NEW CONTINUOUS HYDRIDE GENERATOR FOR THE DETERMINATION OF ARSENIC, ANTIMONY AND TIN BY HYDRIDE GENERATION ATOMIC-ABSORPTION SPECTROMETRY, Analytica chimica acta, 258(2), 1992, pp. 307-315
A new continuous hydride generator is described. Its characteristics a
re compared with a conventional hydride generator for the determinatio
n of arsenic, antimony and tin by using flame atomic absorption spectr
ometry. This simple hydride generator combines hydride production and
gas-liquid separation in one unit, obviating the use of a separate mix
ing/reaction coil and gas-liquid separator. Radioactive tracer studies
show that a hydride generation efficiency of over 95% is achieved wit
h the new hydride generator and that approximately 90% of monomethylar
sonic acid (MMA) is converted to its hydride (methylarsine) within the
first 10 s of the hydride generation reaction. Compared to a conventi
onal hydride generator, an improved signal-to-noise ratio is achieved
and comparable or less interference from transition metal ions is obse
rved. Cysteine (1% in the sample solution) is effective in reducing in
terferences during the hydride generation processes. In the presence o
f cysteine, 10-1000 fold higher amounts of Ni2+, Co2+ and Cu2+ are tol
erated in the determination of arsenic, antimony and tin. Cysteine als
o enhances the signals of arsenic, antimony and tin by 60, 200 and 40%
, respectively. Reaction conditions were optimized by using both the s
implex optimization method and one-factor-at-a-time method and results
are in good agreement.