关键词: 富硒大米, 有机硒, 无机砷, LC-ICP-MS法

Abstract: Using liquid chromatography inductively coupled plasma mass spectrometry （LC-ICP-MS） technology,a method for simultaneous detection of organic selenium and inorganic arsenic in selenium-rich rice had been established, which was used to detect the content of organic selenium and inorganic arsenic in selenium-rich rice sold in Hubei Province. The pre-treatment method for selenium rich rice involved the mixed extraction by using of 15 mg proteinase E and 15 mg proteinase K,the chromatographic conditions were performed using an AgClient ZORBAX SB Aq column, and the mobile phase consistd of a 20 mmol/L citric acid solution, a 5 mmol/L sodium hexane sulfonate solution, and a 1% methanol solution （pH=4.0）. Sample in jection was conducted at a flow rate of 1 mL/min, mass spectrometry used HEHe mode, and three types of organic selenium and two types of inorganic arsenic were separated completely within 5 minutes. The three types of organic selenium and two types of inorganic arsenic showed a good linear relationship ranging from 1 to 50 μg/L, with correlation coefficients （R²） greater than 0.999 0;the detection limits of As （Ⅴ）, As （Ⅲ）, SeCys2, MeSeCys, and SeMet were 0.10, 0.12, 0.18, 0.15, and 0.15 μg/L, respectively, which met the detection requirements. The recovery rate of inorganic arsenic was 96.2%~101.3%, with a relative standard deviation of 2.5%~3.9%;the recovery rate of organic selenium was 72.4%~100.6%, with a relative standard deviation of 2.1%~4.1%. This method was easy to operate, fast, and highly sensitive, and could be used for simultaneous detection of organic selenium and inorganic arsenic in selenium rich rice.

Key words: selenium rich rice, organic selenium, inorganic arsenic, LC-ICP-MS method