Analytical Sciences

Solid Phase Extraction Using a Sulfoxide Adsorbent for Preconcentration and Separation of Hg(II) in Natural Water Followed by ICP-MS Measurements

Yanbei ZHU, Ben AHMADY, Masahiko NUMATA, and Koichi CHIBA

National Metrology Institute of Japan, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Umezono, Tsukuba, Ibaraki 305-8563, Japan

A separation and preconcentration method based on solid-phase extraction using sulfoxide adsorbent was developed for the determination of Hg(II) in natural water samples by inductively coupled plasma mass spectrometry (ICP-MS). The sulfoxide adsorbent was packed into a commercially available syringe-driven column (with a bed volume of 1.0 mL), which permitted off-line sample loading and on-line elution/measurement. The optimized operating conditions were as follows: sample condition for Hg(II) adsorption, 0.5% HCl; sample-loading flow rate, 10 mL min⁻¹; eluent for recovering Hg(II), 1% cysteine water solution. A test using multi-element mixed solution showed that most trace elements in natural water, except for Bi, could be completely separated from Hg(II). The recoveries of Hg(II) were 99.0 ± 3.2 and 100.7 ± 4.3%, respectively, when 0.64 and 0.16 ng mL⁻¹ of Hg(II) were added into the test sample. The detection limit of Hg(II) using a quadrupole ICP-MS after 10-fold preconcentration was 1.5 pg mL⁻¹. The blank value was 2.8 ± 0.5 pg mL⁻¹.

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