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ARS Home » Northeast Area » Wyndmoor, Pennsylvania » Eastern Regional Research Center » Microbial and Chemical Food Safety » Research » Publications at this Location » Publication #381918
Research Project: Development, Evaluation, and Validation of Technologies for the Detection and Characterization of Chemical Contaminants in Foods

Location: Microbial and Chemical Food Safety

Title: Ultratrace mercury speciation analysis in rice by on-line solid phase extraction-liquid chromatography-atomic fluorescence spectrometry

Author
item YAO, ZHENZHEN - Chinese Academy Of Agricultural Sciences
item LI, XUE - Chinese Academy Of Agricultural Sciences
item LIU, JIXIN - Chinese Academy Of Agricultural Sciences
item MAO, XUEFEI - Chinese Academy Of Agricultural Sciences
item Chen, Guoying

Submitted to: Journal of Food Analytical Methods
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/7/2022
Publication Date: 1/10/2022
Citation: Yao, Z., Li, X., Liu, J., Mao, X., Chen, G. 2022. Ultratrace mercury speciation analysis in rice by on-line solid phase extraction-liquid chromatography-atomic fluorescence spectrometry. Journal of Food Analytical Methods. https://doi.org/10.1016/j.foodchem.2022.132116.
DOI: https://doi.org/10.1016/j.foodchem.2022.132116

Interpretive Summary: Mercury in rice may cause health concerns in areas where rice is the staple food. Methylmercury (MetHg) is more toxic than its inorganic counterpart, Hg++. To determine both species at ultra-trace level, a preconcentration method was developed using a modified minicolumn to enrich these mercury species, which were then transported to a liquid chromatographic column for separation, and finally detected by atomic fluorescence spectrometry. This method gained speed, cost and sensitivity advantages.

Technical Abstract: Hg2+ and methylmercury (MetHg) speciation analysis was accomplished by on-line solid phase extraction (SPE) -liquid chromatography-atomic fluorescence spectrometry (LC-AFS). After modification with 0.1 mL of 0.001% (m/v) sodium diethyldithiocarbamate (DDTC), a C18 SPE microcolumn retained Hg2+ and MetHg in rice extract within 3 min; the captured Hg species were separated within 12 min using a 150-mm C18 column and 0.5% (m/v) ammonium acetate + 0.25% (v/v) 2-mercaptoethanol + 40% (v:v) acetonitrile as mobile phase. Under optimized conditions, the detection limits were 0.3 ng L-1 for Hg2+ and 0.2 ng L-1 for MetHg, respectively, with 10 mL injection; on-line SPE achieved ~100x enrichment. Method precision and accuracy were satisfactory at <3% relative standard deviations (RSDs) and >90% recoveries for 20 ng L-1 of Hg2+ and MetHg. On-line SPE obviated human involvement, rendering this SPE-LC-AFS method easy, compact, robust, yet sensitive in mercury speciation analysis to uphold food safety.