反相离子对色谱-电感耦合等离子体质谱联用技术测定水中痕量Cr(III)与Cr(VI)

A method was developed to simultaneously determine trace chromium species in water using ion-pairing reversed phase chromatography (RPIPC)-inductively coupled plasma mass spectrometer (ICP-MS). The chromatographic parameters were optimized to get the best separation, including the pH value of mobile phase, the concentrations of ion-pair reagent and methanol and the addition of EDTA in the mobile phase. The optimium mobile phase was 2.0 mmol/L tetrabutylammonium (TBA), 5% methanol (v/v), pH=5.5. Using collision cell technology to eliminate the mass interferences of 40Ar12C(superscript +) and 35Cl16OH(superscript +) in the analysis of 52Cr(superscript +), and the detection limits of Cr (Ⅲ) and Cr (Ⅵ) were 0.15 μg/L and 0.16 μg/L for 100 μL injections. The recovery range of spiked Cr (Ⅲ) and Cr (Ⅵ) in water samples was 93.6%-106.2% and the RSDs were less than 4% (n=3). The results were satisfying when analyzing the chromium speciation in drinking water and rain water using this method.