固相萃取-原子吸收法测定腌制品中的铅

Determination of Pb in Pickled Products by AAS with Solid-phase Extraction

建立固相萃取-原子吸收光谱法(solid phase extraction-atomic absorption spectrometry,SPE-AAS)测定腌制品中铅的方法。样品经微波消解赶酸后用醋酸铵缓冲溶液调节pH值,然后流经固相萃取柱,保留富集样液中的铅离子,去除氯化钠等盐分,固相萃取柱经5%硝酸洗脱后,用石墨炉原子吸收法在283.3 nm处对铅进行测定。结果表明:该方法测定腌制品中铅,线性相关系数可达0.999 3,检出限为0.01 mg/kg,定量检出限为0.03 mg/kg,同一样品重复试验6次RSD为2.6%。该方法能够有效去除腌制品中的氯化钠等盐分,大大降低原子吸收光谱仪检测腌制品中铅的基体干扰,显著提高腌制品中铅检测的准确性和重复性。

A method for the determination of lead in pickled products by atomic absorption spectrometry with solid-phase extraction was developed.The sample was digested by microwave and the pH was adjusted by ammonium acetate buffer after removing the acid.Then let the solution flow through the solid phase extraction column.Lead was chelated on the solid phase extraction column and separated from NaCl.The graphite furnace atomic absorption method was used to determine lead at 283.3 nm after the solid phase extraction column was washed by 5%nitric acid.Using this method to measure lead in pickled products,the linear correlation coefficient was 0.999 3,the detection limit was 0.01 mg/kg,the quantitative detection limit was 0.03 mg/kg,and the RSD for repeated tests(6)was 2.6%.The results showed that this method could effectively remove the NaCl matrix in pickled products,greatly reduce the interference of matrix during the detection of pickled products by AAS,significantly improve the accuracy and repeatability in the detection of lead in pickled products.