建立了以交联羧甲基魔芋葡甘聚糖(CCMKGM)为微柱预富集-GFAAS测定转基因水稻糙米中痕量铅和镉的新方法。 考察了溶液的pH值、 样品流速和体积、 洗脱液的浓度和体积及共存离子干扰等因素对CCMKGM微柱吸附重金属的影响。 结果表明: 在优化条件下, 方法用于富集、 测定转基因水稻及亲本糙米中Pb和Cd的检出限分别为0.11和0.002 μg·L-1； 测定大米标准参考物质中Pb和Cd的含量, 结果与标准参考值相吻合。 对转基因水稻及亲本糙米进行标准加入回收实验及测定, 回收率分别在90%～103%和93%～105%范围。 该研究可为转基因水稻中痕量Pb和Cd分析提供技术支持。

A novel method was developed for the determination of trace lead and cadmium in transgenic brown rice based on separation and preconcentration with a micro column packed with crosslinked carboxymethyl konjac glucomannan (CCMKGM) prior to its determination by graphite furnace atomic absorption spectrometry. Variables affecting the separation and preconcentration of lead and cadmium, such as the acidity of the aqueous solution, sample flow rate and volume, and eluent concentration and volume, were optimized. Under optimized condition, detection limits of the method for the determination of trace lead and cadmium in transgenic brown rice were 0.11 and 0.002 μg·L-1, respectively. The obtained results of lead and cadmium in the certified reference material (GBW10010, GBS1—1) were in good agreement with the certified values. The recoveries were in the range of 90%～103% and 93%～105% for detection of Pb and Cd in transgenic brown rice and the wild-type brown rice samples respectively. This study could provide technical support for determination of trace Pb and Cd in transgenic rice.