Collision/reaction cell ICP-MS with shielded torch and sector field ICP-MS for the simultaneous determination of selenium isotopes in biological matrices

The determinations of selenium isotopes in biological samples were performed using both inductively coupled plasma collision/reaction cell quadruple mass spectrometer (CRC-ICP-QMS) and inductively coupled plasma sector field mass spectrometers (SF-ICP-MS). To significantly decrease the argon-based interferences at m/z 74 (ArAr), 76 ( ArAr, ArAr), 78 ( ArAr), and 80 (ArAr), the gas-flow rates of a helium and hydrogen mixture used in the collision cell were optimized to 1.0 mL/min H and 3.5 mL/min He. Under the optimized condition, the precisions for natural selenium isotope ratio measurements of both instruments were evaluated and compared using 100 ppb Se standard solution. A modified external calibration quantification method was applied for the simultaneous determination of clinically used enriched selinocompounds ( Se-selenate, Se-selenite, Se- methylseleninic acid, Se-methylselenonic acid ) and to examine their fate in rat organs (liver, kidney, and lung). © 2010 Springer Science+Business Media, LLC.