钨丝捕获-电热蒸发原子荧光光谱法直接测定饮料中痕量镉

Direct Determination of Ultra-Trace Amounts of Cadmium in Beverages by Tungsten Coil Trapping Electrothermal Vaporization Atomic Fluorescence Spectrometry

利用钨丝特异性捕获镉（Cd）消除基体干扰，泡沫碳材质电热蒸发器串联原子荧光光谱仪，建立直接进样测定饮料痕量Cd的方法。仪器条件为：泡沫碳材质样品舟进样（10μL），采用灰化（矿泉水100W保持30s，其他饮料基质100W保持50s）与蒸发（70W保持30s）过程分离，Ar-H2（9：1）载气流速为600mL／min。结果表明：方法具有良好的线性，线性范围为0-5ng，相关系数r在0．998以上；10种饮料产品的加标回收率为92．2％～111．8％；方法检出限为0．04gg／L，相对标准偏差（RSD）在10％以内。本方法简单、灵敏、快速（包括样品前处理的分析时间不超过3min），适用于饮料产品痕量Cd的现场快速检测。

A novel direct sampling method to determine cadmium in beverages by solid sampling electrothermal vaporization atomic fluorescence spectrometry （SS-ETV-AFS） was established, where a tungsten coil as a Cd trap was used to remove matrix interferences and foam graphite as an electrothermal vaporizer and a sample boat. In the present study, 10 μL sample was loaded onto a sample boat, and then vaporized with 70 W for 30 s after being ashed with 100 W for 30 s （natural spring water） or 50 s （beverages）, using Ar/H2（9：1） as the carrier gas with a flow rate of 600 mL/min. Results showed that the calibration curve for Cd had good linearity （from 0 to 5 ng）, and a correlation coefficient （r） was more than 0.998; the recovery rates for Cd in 10 kinds of beverages were 92.2%-111.8%. The detection limit was 0.04 μg/L, and the relative standard deviations （RSD） were less than 10%. This method is simple, sensitive, fast （the whole analytical process including sample pretreatment can be completed within 3 min） and suitable for in-field determination of ultra-trace amounts of Cd in beverages.