Collision/Reaction Cell ICP-MS with Shielded Torch and Sector Field ICP-MS for the Simultaneous Determination of Selenium Isotopes in Biological Matrices
2011
Al-Saad, Khalid A. | Amr, Mohammed A. | Helal, Abdulfattah I.
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 (36Ar38Ar), 76 (38Ar38Ar, 40Ar36Ar), 78 (38Ar40Ar), and 80 (40Ar40Ar), the gas-flow rates of a helium and hydrogen mixture used in the collision cell were optimized to 1.0 mL/min H2 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 (77Se-selenate, 82Se-selenite, 76Se-methylseleninic acidIV, 78Se-methylselenonic acidVI) and to examine their fate in rat organs (liver, kidney, and lung).
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