Authors: Kazumi Inagaki Tomohiro Narukawa Takashi Yarita Akiko Takatsu Kensaku Okamoto Koichi Chiba
Publish Date: 2007/06/28
Volume: 389, Issue: 3, Pages: 691-696
Abstract
A coprecipitation method using sample constituents as carrier precipitants was developed that can remove molybdenum which interferes with the determination of cadmium in grain samples via isotope dilution inductively coupled plasma mass spectrometry IDICPMS Samples were digested with HNO3 HF and HClO4 and then purified 6 M sodium hydroxide solution was added to generate colloidal hydrolysis compounds mainly magnesium hydroxide Cadmium can be effectively separated from molybdenum because the cadmium forms hydroxides and adsorbs onto and/or is occluded in the colloid while the molybdenum does not form hydroxides or adsorb onto the hydrolysis colloid The colloid was separated by centrifugation and then dissolved with 02 M HNO3 solution to recover the cadmium The recovery of Cd achieved using the coprecipitation was 97 and the removal efficiency of Mo was approximately 999 An extremely low procedural blank below the detection limit of ICPMS was achieved by purifying the 6 M sodium hydroxide solution via Mg coprecipitation using MgNO32 solution The proposed method was applied to two certified reference materials NIST SRM 1567a wheat flour and SRM 1568a rice flour and CCQMP64 soybean powder Good analytical results with small uncertainties were obtained for all samples This method is simple and reliable for the determination of Cd in grain samples by IDICPMS
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