色谱

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水产品中甲基汞测定的液相色谱-原子荧光光谱联用方法的改进

尚晓虹, 赵云峰, 张磊, 李筱薇, 吴永宁*   

  1. 中国疾病预防控制中心营养与食品安全所, 北京 100021
  • 收稿日期:2011-04-14 修回日期:2011-05-16 出版日期:2011-07-28 发布日期:2011-08-19
  • 通讯作者: 吴永宁,博士生导师,研究员,主要研究方向为食品安全.
  • 基金资助:

    “十一五”国家科技支撑计划项目(2006BAK02A10)和卫生行业公益项目(200902009)

Improvement of the method for methylmercury determination in aquatic products using liquid chromatography online coupled with atomic fluorescence spectrometry

SHANG Xiaohong, ZHAO Yunfeng, ZHANG lei, LI Xiaowei, WU Yongning*   

  • Received:2011-04-14 Revised:2011-05-16 Online:2011-07-28 Published:2011-08-19

摘要: 对本实验室前期建立的食品中甲基汞的液相色谱-原子荧光光谱联用测定方法进行了改进。采用无毒的半胱氨酸代替有毒试剂巯基乙醇作为流动相中的配位剂,流动相组成为5%(v/v)乙腈-1 g/L半胱氨酸-50 mmol/L乙酸铵水溶液,使汞化合物分离时间缩短至8 min。在优化条件下,甲基汞标准曲线的线性范围为1~50 μg/L,检出限(S/N=3)为0.3 μg/L。采用超声波辅助5 mol/L HCl提取样品中的甲基汞,提取液经C18固相萃取小柱净化后进样。鱼、虾、贝等不同种类水产动物样品以及水产类膳食样品的甲基汞加标回收率为89%~112%。对标准参考物质NIST1566b、BCR464和GBW10029以及英国食品分析水平评估计划(Food Analysis Performance Assessment Scheme, FAPAS)的罐装鱼肉样品(样品编号07115)的测定结果与参考物定值相符,验证了该方法的可靠性与准确性。本方法可满足食品中甲基汞检测的需要。

关键词: 甲基汞, 水产品, 形态分析, 液相色谱, 原子荧光光谱

Abstract: The improvement method was developed for methylmercury determination using liquid chromatography online coupled with cold vapor atomic fluorescence spectrometry (LC-CV-AFS). Cysteine was used as complexing agent in mobile phase instead of mercaptoethanol. Under the optimized conditions, baseline separation of mercury species could be achieved within 8 min on a C18 column with a mobile phase of 5% (v/v) acetonitrile-1 g/L L-cysteine-50 mmol/L ammonium acetate aqueous solution. The linear range of calibration curve of methylmercury was 1~50 μg/L and the limit of detection (S/N=3) for methylmercury was 0.3 μg/L. Ultrasonication assisted hydrochloric acid extraction was used to extract methylmercury from seafood samples. The sample extract was cleaned up by a C18 solid phase extraction (SPE) cartridge. For validation of the method, certified reference materials and spiked seafood samples were analyzed. The determined methylmercury contents of certified reference materials NIST1566b、BCR464 and GBW10029 agreed well with the certified values. The determined methylmercury values for Food Analysis Performance Assessment Scheme (FAPAS) sample 07115 were satisfied. The recoveries of methylmercury in seafood samples at three spiked levels (10, 50 and 500 μg/kg) ranged from 89% to 112%, including cooked seafood food. The precision of the method based on relative standard deviation (RSD) was not more than 7%. The present method of LC-CV-AFS is accurate, sensitive, simple, and can meet the demand of methylmercury determination in seafood.

Key words: aquatic products, methylmercury, species analysis, atomic fluorescence spectrometry(AFS), liquid chromatography (LC)