Speciation analysis of mercury in seafood by using high-performance liquid chromatography on-line coupled with cold-vapor atomic fluorescence spectrometry via a post column microwave digestion

Abstract

An automatic system, based on the on-line coupling of high-performance liquid chromatography (HPLC) separation, post column microwave digestion, and cold-vapor atomic fluorescence spectrometry (CVAFS) detection, was proposed for the speciation analysis of four mercury compounds. Post column microwave digestion, in the presence of potassium persulfate (in HCl), was applied in the system to improve the conversion efficiency of three organic mercury compounds into inorganic mercury. Parameters influencing the on-line digestion efficiency and the separation effect were optimized. To avoid water vapor and methanol entering into the atomic fluorescence detector, ice-water mixture bath was used to cool the microwave-digested sample solution. Four mercury species including inorganic mercury chloride (MC), methylmercury chloride (MMC), ethylmercury chloride (EMC) and phenylmercury chloride (PMC) were baseline separated within 13 min by using RP C 18 column with a mobile phase of 50% (v/v) methanol containing 10 mmol l −1 tetrabutyl ammonium bromide and 0.1 mol l −1 sodium chloride pumped at 1.2 ml min −1 . Seafood samples, composed of three gastropod species and two bivalve species from Yantai port, China, have been analyzed by the proposed method. Dogfish muscle (DORM-2) was analyzed to verify the accuracy of the method and the result was in good agreement with the certified value.

The speciation and bioavailability of mercury in sediments of Haihe River, China

“…Our results for HgT were 275F11 ng g À1 (n=5) in GBW07310 and 22F4 ng g À1 (n=5) in GBW08302, respectively. The HPLC-CVAFS system was validated with certified reference material DORM-2 (Dogfish muscle) and the result was in good agreement with the certified values (Liang et al, 2003a). Due to lack of sediment certified reference materials (CRMs) for MeHg in our laboratory, 10 and 100 AL of 1 Ag mL À1 MeHg standard solutions were respectively added into sediments of S5 and S11 collected on July 12-13.…”

“…The determination of methylmercury in sediments was based on acid extraction (Wilken and Hintelmann, 1991;Hintelmann et al, 1997) and HPLC-CVAFS technique published previously (Liang et al, 2003a) with the following modifications. Ten grams of sediment were weighed into a 250-mL flask and 50 mL of 6 mol L À1 HCl solution was added.…”

UV Irradiation Controlled Cold Vapor Generation Using SnCl2 as Reductant for Mercury Speciation

“…[19][20][21][22][23] On the other hand, some metals in their organic states can also be converted to the inorganic state in aqueous solution with or without oxidation reagent, i.e., Hg 2+ , with UV irradiation, and then such metals can be determined by liquid chromatography and/or atomic spectrometry. [24][25][26][27] But these techniques all need a separation or extra pretreatment procedure. In our previous work, with formic acid as a reductant, photo-induced chemical vapor generation was used for the determination of Hg 2+ and MeHg by atomic fluorescence spectrometry, with the limit of detection of 0.003 μg L -1 for total mercury with the UV or 0.2 μg L -1 for Hg 2+ with the Vis.…”

Investigation of Methylmercury and Total Mercury Contamination in Mollusk Samples Collected from Coastal Sites along the Chinese Bohai Sea

“…The methylmercury was determined with our previously proposed HPLC-AFS method (4), but the sample preparation was slightly modified in order to shorten the preparation time. The AFS method was adopted for the total mercury determination.…”