固相萃取富集-高效液相色谱法测定烟草和烟草添加剂中的重金属元素

HPLC DETERMINATION OF SOME HEAVY METAL ELEMENTS IN TOBACCO AND TOBACCO ADDITIVES AFTER PRECONCENTRATION BY SOLID PHASE EXTRACTION

研究了用固相萃取富集,高效液相色谱法测定烟草及烟草添加剂中镍、铜、锡、铅、镉、汞的方法。样品用微波消化后,消化液中镍、铜、锡、铅、镉、汞用四 (对氨基苯基) 卟啉[T (p AP)P]柱前衍生,用C18固相萃取小柱萃取富集镍、铜、锡、铅、镉、汞的T (p AP)P络合物,富集倍数为50倍;然后用甲醇和丙酮(均含0.05mol·L-1的pH10.0四氢吡咯 乙酸缓冲)为流动相进行梯度洗脱,WatersXterraTMRP18(3.9mm×150mm)为色谱柱,用二极管矩阵检测器检测。镍、铜、锡、铅、镉、汞的检出限分别为42,38,82,60,50和25ng·L-1。RSD为2.1%～2.8%,标准回收率为95%～103%。该方法用于测定烟草及烟草添加剂中的痕量镍、铜、锡、铅、镉、汞,结果满意。

It is reported that the tobacco sample was digested with conc. HNO_3 and H_2O_2 by heating in a micro wave oven, and cations of Ni Cu Sn Pb Cd and Hg in the digested solution were preconcentrated on C_(18) solid phase extraction column in the form of their T-(p-AP)P complexes pre-column derivatized. The multiple of preconcentration achieved to a value of 50. Gradient elution was applied in the separation of the porphyrin complexes by using two solutions as mobile phase. Solution A is methane containing 0.05mol·L^(-1) of tetrahydropyrrole-acetate buffer of pH 10.0, and solution B is acetone containing the same amount of buffer and of same pH value. Twenty μl of the eluate were used in the chromatography on a Waters Xterra^(TM)RP_(18) (5μm, 3.9mm×150mm) column. Detections were made by photodiode array detectors at appropriate wavelength. The detection limits of Ni^(2+) Cu^(2+) Sn^(4+) Pb^(2+) Cd^(2+) and Hg^(2+) were found to be 42ng·L^(-1), 38ng·L^(-1), 82ng·L^(-1), 60ng·L^(-1), 50ng·L^(-1) and 25ng·L^(-1) respectively. In the application of this method to the analysis of tobacco and additives samples, and in comparison with the AAS method, satisfactory and consistent results were obtained.