高效液相色谱-原子荧光光谱联用测定土壤中3种痕量汞形态

Determination of Three Kinds of Mercury Species in Soils by High Performance Liquid Chromatography-Atomic Fluorescence Spectrometry

建立了高效液相色谱-原子荧光法测定土壤中二价汞、甲基汞、乙基汞3种汞形态的分析方法。对提取溶液、液相色谱柱、流动相及其pH值、载流HCl、还原剂KBH 4溶液及氧化剂K 2S 2O 8溶液等条件进行了优化。实验表明:在以10%HCl+10.0 g/L硫脲+15.0 g/L KCl为提取溶液,反相C18柱(150 mm×4.6 mm,5μm)为色谱柱,5%甲醇+60 mmol/L乙酸铵+1.0 g/L L-半胱氨酸溶液为流动相(pH=6.00±0.02),10%HCl溶液为载流,5.0 g/L KOH+15.0 g/L KBH 4溶液为还原剂,5.0 g/L KOH+10.0 g/L K 2 S 2 O 8溶液为氧化剂等条件下,二价汞、甲基汞、乙基汞3种汞形态在10 min内可完全分离;校准曲线线性相关系数均大于0.999;方法检出限分别为0.01 mg/kg、0.006 mg/kg、0.008 mg/kg;实验室内相对标准偏差范围为5.4%~16.7%,加标回收率范围为75.4%~91.8%。本方法前处理过程简单,检出限低、精密度好、准确度高,能够快速定性、准确定量检测土壤中3种痕量汞形态。

A method was developed for the determination of inorganic mercury,methyl mercury,and ethyl mercury in soil by high performance liquid chromatography-atomic fluorescence spectrometry(HPLC-AFS).The experimental conditions were optimized as follows:the reversed phase C18 column(Agela MP-C18,150 mm×4.6 mm i.d.,5μm)was used as stationary phace mixed solution of HCl(10%),thiourea(10.0 g/L)and KCl(15.0 g/L)was used as extraction solution,mixed solution of HCl(5%),ammonium acetate(60 mmol/L)and L-cysteine(1.0 g/L)was used as mobile phase(pH=6.00±0.02),HCl(10%)solution was used as current-carrying reagent,mixed solution of KOH(5.0 g/L)and KBH 4(15.0 g/L)was used as reducing reagent,mixed solution of KOH(5.0 g/L)and K 2 S 2 O 8(10.0 g/L)was used as oxidizer.The experimental results showed that inorganic mercury,methyl mercury and ethyl mercury could be completely separated and detected within 10 min.The linear correlation coefficients(r)of the calibration curves were all greater than 0.999.The detection limits were 0.01,0.006 and 0.008 mg/kg,respectively.The relative standard deviation was 5.4%-16.7%,and the recovery was 75.4%-91.8%.This method has the advantages of simple pre-treatment,low detection limit,good precision and high accuracy,and can be used for rapid and accurate quantitation of three mercury species in soil.