微波消化-在线固相萃取富集高效液相色谱法测定饲料用灌木中痕量铅镉汞

STUDY ON THE HPLC DETERMINATION OF TRACE AMOUNTS OF Pb Cd AND Hg IN FEEDING SHRUBBERY WITH ON-LINE PRECONCENTRATION AND SAMPLE DIGESTION BY MICROWAVE HEATING

研究了用微波消化样品,WatersXterraTMRP18(3.9mm×20mm)色谱柱在线固相萃取富集,二极管矩阵检测器检测,高效液相色谱测定饲料用灌木中痕量铅、镉、汞的方法。铅、镉和汞含量在0.1～100μg·L-1范围内与峰面积呈线性关系,方法检出限(S/N=3)为:铅2.0ng·L-1,镉1.5ng·L-1和汞2.0ng·L-1,方法相对标准偏差为2.0%～3.1%,标准回收率为94%～103%,该方法用于测定饲料用灌木中低含量的铅、镉、汞,结果满意。

The shrubbery sample was digested and heated with conc. HNO_3 and hydrogen peroxide, in a microwave oven. An aliquot of the sample solution was used for the HPLC determination of trace amounts of Pb(Ⅱ) Cd(Ⅱ) and Hg(Ⅱ), after pre-column derivatization with TMPP and pre-concentration on the enrichment column. The absorption spectra of the complexes of Pb(Ⅱ) Cd(Ⅱ) and Hg(Ⅱ) with TMPP were recorded and their peak areas measured by the array diode detector (waters 996). Linear relationships between the peak areas and concentrations of ions of lead, cadmium and mercury were obtained in the range of 0.1～100μg·L^(-1). Detections limits (S/N=3) of 2.0ng·L^(-1) (for Pb), 1.5ng·L^(-1) (for Cd) and 2.0ng·L^(-1) (for Hg) were obtained. Recoveries found by the standard addition method were in the range of 94%～103%. RSD′s (n=5) obtained in the analysis of some samples were less than 3.1%.