响应面法优化提取-原子吸收光谱法测定茶叶中的铅

Determination of Lead in Tea Leaves by AAS-Optimization of Extraction with Response Surface Method

研究超声辅助提取(UAE)快速测定茶叶铅。采用Plackett-Burman设计和响应面法得优化提取条件:200mg样品中加入HNO3∶H2O2(1∶1,V/V)5mL浸泡6min、78℃超声8.4min。对GBW 10016茶叶,该法测定值与标准值符合,加标回收率为96.0%—102.2%,检出限0.041μg.L-1,重复测定的RSD为6.3%。该法测定45个茶鲜叶和10种商品茶,铅含量(干基)在0.39—1.22mg.kg-1之间,与湿法消解(WAD)结果无显著差异。

A rapid ultrasound-assisted extraction（UAE） method for the determination of lead in tea leaves was developed.The optimized conditions were obtained by a Plackett-Burman design and response surface methodology as follows：HNO3∶H2O2（1∶1,V/V）5mL was added to 200mg sample by ultrasound extraction for 8.4min at 78.0℃ after soaking 6min.The detection results showed the good agreement with the certified values of GBW 10016.Recovery,detection limit and RSD of replicate measurements were 96.0%—102.2%,0.041μg·L-1 and 6.3%,respectively.The Pb concentrations of 45 fresh tea leaves and 10 branded tea were determined to be 0.39—1.22mg·kg-1 on a dried basis.No significant differences were found between UAE method and WAD method.