Simple solvent extraction technique for elimination of matrix interferences in the determination of methylmercury in environmental and biological samples by ethylation-gas chromatography-cold vapor atomic fluorescence spectrometry

Rice consumption contributes to low level methylmercury exposure in southern China

“…For total mercury (THg) analysis, rice samples were digested in a water bath (95°C) with a fresh mixed acid of HNO 3 :H 2 SO 4 (4:1, v/v) (Horvat et al, 1991) and determined by SnCl 2 reduction, purge, gold trap, and cold vapor atomic fluorescence spectrometry (CVAFS) detection according to USEPA Method 1631(USEPA, 1999. For MeHg measurement, rice samples were digested using the KOH-methanol/solvent extraction technique (Liang et al, 1994(Liang et al, , 1996 and measured by aqueous ethylation, purge, trap, and gas chromatography (GC) coupled with CVAFS detection according to USEPA Method 1630(USEPA, 2001. Detail information of quality control is available in the Supporting information.…”

Speciation of methylmercury in rice grown from a mercury mining area

“…For MeHg T analysis, 0.3e0.5 g of rice sample (cooked or uncooked) was digested using a KOHemethanol extraction technique (Liang et al, 1994(Liang et al, , 1996 and determined by gas chromatography e cold vapour atomic fluorescence spectroscopy (GC-CVAFS; Brooks Rand Model III) according to U.S. EPA method 1630 (USEPA, 2001). The DL was 2 ng kg À1 for MeHg T .…”

Studies of biouptake and transformation of mercury by a typical unicellular diatom Phaeodactylum tricornutum

“…It is well documented that MeHg can be transformed from inorganic Hg in natural waters via biological ways (for example, periphyton [32], plankton produced iodomethane [33], macroalgae [34,35] and especially anoxic bacteria such as sulfate-reducing bacteria [36] in deep and littoral sediments are found to produce methylated mercury) and non-biological ways [37] (such as methyltin, methylcobalamin and humic matter in sediments). In order to verify the production of MeHg when P. tricornutum was exposed to HgCl 2 , we detected and identified MeHg in both the intracellular extract of P. tricornutum and the corresponding culture solution using HPLC-AFS and GC-MS. MeHg was detected in the P. tricornutum culture solutions using HPLC-AFS ( Figure 6(b)) strictly following the MeHg extraction protocols [21], but no MeHg was detected in the control culture solutions containing no P. tricornutum. and 120 g L -1 , respectively), the amounts of MeHg produced were found to be 2.1, 6.2 and 9.8 µg g -1 DW inside P.…”

“…Cells were collected from 400 mL P. tricornutum suspensions under HgCl 2 exposure (20, 80 and 120 g L -1 , respectively) via centrifugation at 4000×g. The obtained cell pellets and corresponding culture solutions were subjected to the following treatments: the cell pellets were resuspended in 10 mL 0.01 mol L -1 DTE for 10 min to wash off any surface-adsorbed Hg, then the cells were collected via centrifugation at 5000 g; after being resuspended in 2 mL KOH/CH 3 OH (25%, w/v) solution [21], the cells were ultrasonicated then the homogenized suspension was extracted three times using 3 mL CH 2 Cl 2 on a SKY-200B rocker (SUKUN, Shanghai, China) at 250 r/min for 1 h each time. After the CH 2 Cl 2 phases obtained were combined and concentrated under a N 2 -blow, they were subjected to HPLC/CVG-AFS.…”