Speciation analysis of mercury by dispersive solid-phase extraction coupled with capillary electrophoresis

Jinhua Li; Junying Liu; Wenhui Lu; Fangfang Gao; Liyan Wang; Jiping Ma; Huitao Liu; Chunyang Liao; Lingxin Chen

doi:10.1002/elps.201800024

Speciation analysis of mercury by dispersive solid-phase extraction coupled with capillary electrophoresis

Electrophoresis. 2018 Apr 23. doi: 10.1002/elps.201800024. Online ahead of print.

Authors

Jinhua Li¹, Junying Liu^{1

2}, Wenhui Lu¹, Fangfang Gao^{1

2}, Liyan Wang¹, Jiping Ma³, Huitao Liu², Chunyang Liao⁴, Lingxin Chen^{1

2}

Affiliations

¹ Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Research Center for Coastal Environmental Engineering Technology of Shandong Province, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, P. R. China.
² College of Chemistry and Chemical Engineering, Yantai University, Yantai, P. R. China.
³ School of Environmental and Municipal Engineering, Qingdao Technological University, Qingdao, P. R. China.
⁴ State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, P. R. China.

PMID: 29683516
DOI: 10.1002/elps.201800024

Abstract

A pretreatment method of dispersive solid-phase extraction (DSPE) along with back-extraction followed by CE-UV detector was developed for the determination of mercury species in water samples. Sulfhydryl-functionalized SiO₂ microspheres (SiO₂ -SH) were synthesized and used as DSPE adsorbents for selective extraction and enrichment of three organic mercury species namely ethylmercury (EtHg), methylmercury (MeHg), and phenylmercury (PhHg), along with L-cysteine (L-cys) containing hydrochloric acid as back-extraction solvent. Several main extraction parameters were systematically investigated including sample pH, amount of adsorbent, extraction and back-extraction time, volume of eluent, and concentration of hydrochloric acid. Under optimal conditions, good linearity was achieved with correlation coefficients over 0.9990, in the range of 4-200 μg/L for EtHg, and 2-200 μg/L for MeHg and PhHg. The LODs were obtained of 1.07, 0.34, and 0.24 μg/L for EtHg, MeHg, and PhHg, respectively, as well as the LOQs were 3.57, 1.13, and 0.79 μg/L, respectively, with enrichment factors ranging from 109 to 184. Recoveries were attained with tap and lake water samples in a range of 62.3-107.2%, with relative standard deviations of 3.5-10.1%. The results proved that the method of SiO₂ -SH based DSPE coupled with CE-UV was a simple, rapid, cost-effective, and eco-friendly alternative for the determination of mercury species in water samples.

Keywords: Capillary electrophoresis; Dispersive solid-phase extraction; Mercury species; Speciation analysis; UV detection.