高效液相色谱-原子荧光光谱法测定土壤中4种有效硒形态

Determination of Four Available Selenium Species in Soils by High Performance Liquid Chromatography-Atomic Fluorescence Spectrometry

建立高效液相色谱-原子荧光光谱法(HPLC-AFS)测定土壤中硒酸根、亚硒酸根、硒代胱氨酸、硒代蛋氨酸4种有效硒形态的分析方法。采用不同pH值的KH_(2)PO_(4)溶液为提取液,对不同酸碱度的土壤样品进行浸提,以Hamilton PRP-X100阴离子交换色谱柱分离,流动相为40 mmol/L(NH_(4))_(2)HPO_(4)溶液(pH=6.0),以20 g/L的KBH 4溶液和10 g/L KI溶液为还原剂,7%HCl为载流溶液。硒酸根、亚硒酸根、硒代胱氨酸、硒代蛋氨酸在20 min内可完全分离,校准曲线线性相关系数(r)均大于0.999;方法检出限分别为0.02 mg/kg、0.02 mg/kg、0.04 mg/kg和0.1 mg/kg;相对标准偏差范围为1.2%~13.7%,加标回收率范围为67.6%~94.7%。本方法能够简便、快速、灵敏检测土壤样品中4种形态有效硒。

A method was developed for the determination of four available selenium species including selenate,selenite,selenocystine and selenomonine in soil by high performance liquid chromatography-atomic fluorescence spectrometry.The potassium dihydrogen phosphate solutions with different pH values were used to extract the different acidity or alkalinity soil samples.A Hamilton PRP-X100 reversed-phase anion exchange column was used for separation.The diammonium phosphate solution with 40 mmol/L(pH=6.0)was used as the mobile phase.The potassium borohydride solution with 20 g/L and potassium iodide solution with 10 g/L were reducing agents.The hydrochloric acid solution with volume fraction of 7%was used for current-carrying solution.The four available selenium species including selenate,selenite,selenocystine and selenomonine were separated completely within 20 min,and the linear correlation coefficients(r)of the calibration curves were all greater than 0.999.The detection limits were 0.02 mg/kg,0.02 mg/kg,0.04 mg/kg and 0.1 mg/kg,respectively.The range of relative standard deviations was about 1.2%-13.7%in laboratory,and the range of recoveries was about 67.6%-94.7%.This method can be used to determine four available selenium species in soils.