摘要
重金属镉(Cd)一直是茶叶产品质量安全关注的重点。本研究基于电热蒸发-催化热解-原子吸收光谱仪(SS-ETV-AAS),使用镍材质样品舟,在300 mL/min空气条件下,350℃干燥20 s,350~725℃灰化55 s;引入300 mL/min氢气与空气反应形成氮氢混合气氛,在725~800℃(50 s)下完成Cd的蒸发;之后,在高岭土填料催化热解炉800℃和准直管700℃条件下,氮氢火焰原子吸收测定镉的含量。方法检出限(LOD)为0.3 ng/g、定量限(LOQ)为1.0 ng/g,R^(2)>0.998,多次测定的相对标准偏差(RSD)为1.8%~8.6%,多种茶叶样品中Cd的测定值与微波消解石墨炉原子吸收光谱法(GFAAS)无显著性差异(P>0.05),Cd的回收率在92%~107%之间。试验结果表明,该方法灵敏度高、稳定性好、简单高效,且无需消解处理,样品分析时间仅为3min,适用于茶叶中Cd的快速检测。
The heavy metal cadmium(Cd)has always been the focus of quality and safety concerns in tea products.In this work,an analytical method was established based on the electrothermal vaporization-catalytic pyrolysis-atomic absorption spectrometry(SS-ETV-AAS).Tea sample was loaded into the nickel boat,and then dried at 350℃for 20 s and 350~725℃ashed for 55 s under 300 mL/min air atmosphere.Cd was vaporized under 725~800℃(50 s)when switching on 300 mL/min H 2 to react with air to form N 2/H 2,in which the catalytic pyrolysis furnace with kaolin filler at 800℃fulfilled Cd transportation to pass the integrated quartz tube(IOT).IOT under 700℃heating yields N 2/H 2 flame to keep Cd atoms for the AAS detection.The proposed method detection limit(LOD)was 0.3 ng/g,quantitation limit was 1.0 ng/g with R^(2)>0.998 and the relative standard deviations(RSD)were 1.8%~8.6%with multiple measurements.The Cd concentrations measured by the proposed method had no significant difference with that by the microwave digestion graphite furnace AAS(GFAAS)method(P>0.05),furthermore,the recoveries were 92%~107%proving favorable accuracy.Our results proved the proposed method was high sensitivity,good stability,simplicity and efficiency without acid digestion process.The whole analytical time was only 3 min,which is extremely suitable to fast detection of Cd in tea sample.
作者
邢培哲
李雪
章剑扬
冯礼
刘贵巧
毛雪飞
XING Pei-zhe;LI Xue;ZHANG Jian-yang;FENG Li;LIU Gui-qiao;MAO Xue-fei(Heibei University of Engineer,Handan 056038,China;Institute of Quality Standard and Testing Technology for Agro-products,Chinese Academy of Agricultural Sciences/Key Laboratory of Agro-food Safety and Quality,Ministry of Agriculture and Rural Affairs,Beijing 100081,China;Tea Research Institute,Chinese Academy of Agricultural Sciences/Laboratory of Quality and Safety Risk Assessment of Tea Products,Ministry of Agriculture and Rural Affairs,Hangzhou 310008,China;Changsha Kaiyuan Hongsheng Technology Co.Ltd.,Changsha 410000,China)
出处
《中国食物与营养》
2021年第1期24-29,共6页
Food and Nutrition in China
基金
国家自然科学基金面上项目(项目编号:32072307)。
关键词
固体进样
电热蒸发
催化热解
原子吸收
茶叶
镉
solid sampling
electrothermal vaporization
catalytic pyrolysis
atomic absorption spectrometry
tea
cadmium
