Arsenic speciation based on ion exchange high-performance liquid chromatography hyphenated with hydride generation atomic fluorescence and on-line UVphoto oxidation
B. He et al., Arsenic speciation based on ion exchange high-performance liquid chromatography hyphenated with hydride generation atomic fluorescence and on-line UVphoto oxidation, FRESEN J AN, 368(8), 2000, pp. 803-808
An on-line method capable of the separation of arsenic species was develope
d for the speciation of arsenite As(III), arsenate As(V), monomethylarsenic
(MMA) and dimethylarsenic acid (DMA) in biological samples. The method is
based on the combination of high-performance liquid chromatograph (HPLC) fo
r separation, UV photo oxidation for sample digestion and hydride generatio
n atomic fluorescence spectrometry (HGAFS) for sensitive detection. The bes
t separation results were, obtained with an anion-exchange AS11 column prot
ected by an AG11 guard column, and gradient elution with NaH2PO4 and water
as mobile phase. The on-line UV photo oxidation with 1.5% K2S2O8 in 0.2 mol
L-1 NaOH in an 8 m PTFE coil for 40 s ensures the digestion of organoarsen
ic compounds. Detection limits for the four species were in the range of 0.
11-0.15 ng (20 muL injected). Procedures were validated by analysis of the
certified reference materials GBW09103 freeze-dried human urine and the res
ults were in good agreement with the certified values of total arsenic conc
entration. The method has been successfully applied to speciation studies o
f blood arsenic species with no need of sample pretreatment. Speciation of
arsenic in blood samples collected from two patients after the ingestion of
realgar-containing drug reveals slight increase of arsenite and DMA, resul
ting from the digestion of realgar.