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On‐line coupling of an ultraviolet titanium dioxide film reactor with a liquid chromatography/hydride generation/inductively coupled plasma mass spectrometry system for continuous determination of dynamic variation of hydride‐ and nonhydride‐forming arsenic species in very small microdialysate samples
Author(s) -
Tsai Minewei,
Sun Yuhchang
Publication year - 2007
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.3353
Subject(s) - chemistry , arsenobetaine , inductively coupled plasma mass spectrometry , chromatography , detection limit , mass spectrometry , arsenic , hydride , analytical chemistry (journal) , high performance liquid chromatography , inductively coupled plasma , plasma , metal , physics , quantum mechanics , organic chemistry
Abstract We describe a method for continuously monitoring both hydride‐ and nonhydride‐forming arsenic species in 10‐µL microdialysate samples by coupling together on‐line high‐performance liquid chromatography (HPLC), a post‐column UV/TiO 2 film reactor, and hydride generation (HG) inductively coupled plasma mass spectrometry (ICP‐MS). To maximize the signal intensities of the desired arsenic species, we optimized the photocatalytic oxidation efficiency of the analyte species and used a rapid on‐line pre‐reduction process to convert the oxidized species into As(III) prior to HG‐ICP‐MS determination. The UV/nano‐TiO 2 film reactor was manufactured by coating nano‐TiO 2 onto the interior of a glass tube. Impregnation and sol–gel methods were employed to deposit the TiO 2 films, and their effectiveness for the oxidation of organic arsenicals was compared. To enhance the decomposition efficiency of organic arsenicals, we investigated the effects of the acidity and the composition of the column effluent. Because of the improved HG efficiency toward the tested arsenicals and the adoption of a segmented flow technique to retain the peak resolution in our on‐line LC‐UV/nano‐TiO 2 film reactor‐HG‐ICP‐MS instrument, the detection limits for arseneous acid [As(III)], monomethylarsonic acid (MMA), dimethylarsinic acid (DMA), arsenic acid [As(V)], and arsenobetaine (AsB) were all in the submicrogram‐per‐liter range (based on 3 sigma) for 10‐µL injections. A series of validation experiments – analyses of certified reference urine and rabbit serum samples – indicated that these methods can be applied satisfactorily to the continuous determination of As(III), MMA, DMA, As(V), and AsB in blood and in the extracellular space of target organs. Copyright © 2007 John Wiley & Sons, Ltd.