Most cited article - PubMed ID 25300934
Speciation analysis of arsenic by selective hydride generation-cryotrapping-atomic fluorescence spectrometry with flame-in-gas-shield atomizer: achieving extremely low detection limits with inexpensive instrumentation
Hydride generation (HG) coupled to cryotrapping was employed to introduce, separately and with high selectivity, four gaseous arsanes into a direct analysis in real time source for high-resolution mass spectrometry (DART-HR-MS). The arsanes, i.e., arsane (AsH3), methylarsane (CH3AsH2), dimethylarsane ((CH3)2AsH), and trimethylarsane ((CH3)3As), were formed under HG conditions that were close to those typically used for analytical purposes. Arsenic containing ion species formed during ambient ionization in the DART were examined both in the positive and negative ion modes. It was clearly demonstrated that numerous arsenic ion species originated in the DART source that did not accurately reflect their origin. Pronounced oxidation, hydride abstraction, methyl group(s) loss, and formation of oligomer ions complicate the identification of the original species in both modes of detection, leading to potential misinterpretation. Suitability of the use of the DART source for identification of arsenic species in multiphase reaction systems comprising HG is discussed.
- Keywords
- Ambient ionization, Arsenic, Cryotrapping, Direct analysis in real time, Hydride generation, Mass spectrometry,
- Publication type
- Journal Article MeSH
A method for analysis of toxicologically important arsenic species in blood plasma and whole blood by selective hydride generation with cryotrapping (HG-CT) coupled either to atomic absorption spectrometry (AAS) with a quartz multiatomizer or to inductively coupled plasma mass spectrometry (ICPMS) has been validated. Sample preparation, which involved only 5 times dilution with addition of Triton X-100, Antifoam B, and l-cysteine, suppressed excessive foaming in a hydride generator. Calibration slopes for whole blood and blood plasma spiked with arsenate, monomethylarsonate, and dimethylarsinate at 0.25-1 μg L-1 As and 0.025-0.1 μg L-1 As for AAS and ICPMS detection, respectively, did not differ from slopes in aqueous solutions. HG-CT-AAS was used to analyze samples with elevated levels of arsenic species-blood plasma from patients treated with arsenic trioxide for acute promyelocytic leukemia and whole blood from mice fed an arsenic-containing diet. A good agreement between results of the direct analysis and analysis after mild digestion in phosphoric acid proved the good efficiency of the direct HG-CT procedure for the arsenic species in these types of biological samples. In the next step, plasma and whole blood from healthy donors that were spiked with the plasma from leukemia patients at levels of 0.15-0.4 μg L-1 As were analyzed by direct HG-CT-ICPMS. Good recoveries for all species even at these low levels (88-104%) were obtained. Limits of detection in blood and plasma were 0.014 μg L-1 for inorganic arsenic and below 0.002 μg L-1 As for methylated arsenic species. Thus, the ultrasensitive direct HG-CT-ICPMS method is uniquely suited for analyses of blood plasma and whole blood from individuals at low exposure levels.
