High-performance liquid chromatography-ultrasonic nebulizer high-power nitrogen microwave-induced plasma mass spectrometry, real-time on-line coupling for selenium speciation analysis.
The coupling of a high-power nitrogen (N2) microwave-induced plasma (MIP) mass spectrometry--(MS) (1.3 kW) with high-performance liquid chromatography, connected with concentric nebulizer (CN), ultrasonic nebulizer (USN) and a hydride generation (HG) systems, for the optimization and determination of selenium compounds, has been carried out. The MIP-MS system fulfils the ideal requirement being an on-line real-time chromatographic detector for Se speciation analysis. Interchanging of MIP-MS system fabricated nebulizer (concentric) with an ultrasonic nebulizer increases about 3.4-12 (peak height) and 6.5-10 (peak area) times ion signals for the selenium compounds. The detection limits for selenate, selenite, trimethylselenonium ion (TmSe), selenomethionine (Semet) and selenoethionine (Seet) (in Milli-Q-water) obtained with the optimized HPLC-USN-N2MIP-MS system are 0.11, 0.14, 0.09, 0.14 and 0.10 microg L(-1), respectively, about 12-48 times lower than the HPLC-CN-MIP-MS and 1.5-4.4 (peak height) times lower compared to the HPLC-CN-inductively coupled plasma (ICP)-MS coupling. Considering peak area, the repeatability (R.S.D. for three successive analyses) and intermediate precision (R.S.D. for three successive analyses performed on three different days), achieved for five Se compounds are 0.8-5.6, and 1.1-5.9%, comparable with the HPLC-CN-ICP-MS, HPLC-HG-MIP-MS and HPLC-CN-MIP-MS systems. The combined HPLC-USN-N2MIP-MS has been adequately applied for the determination of Se compounds in certified National Institute for Environmental studies human urine CRM No. 18. The results reasonably agree with the HPLC-CN-ICP-MS values. This encouraging combination may be an alternative ion source of mass spectrometry for coming generation in regard to the selenium speciation analysis.
Chatterjee
Amit
A
Environmental Chemistry Division, Environmental Chemodynamics Section, National Institute for Environmental Studies, 16-2 Onogawa, Ibaraki 305-0053, Tsukuba, Japan. amit@udel.edu
Shibata
Yasuyuki
Y
Tao
Hiroaki
H
Tanaka
Atsushi
A
Morita
Masatoshi
M
D002851:Chromatography, High Pressure Liquid; D005612:Freeze Drying; D006801:Humans; D007202:Indicators and Reagents; D013058:Mass Spectrometry; D008872:Microwaves; D009584:Nitrogen / Q000737:chemistry; D015203:Reproducibility of Results; D018036:Selenium Compounds / Q000032:analysis* / Q000652:urine; D012996:Solutions; D014465:Ultrasonics
D007202:Indicators and Reagents; D018036:Selenium Compounds; D012996:Solutions; D009584:Nitrogen