title: Improvements of reliability for methylmercury determination in environmental samples.
abstract: The determination of methylmercury (MeHg) in environmental samples by ethylation derivation-gas chromatography-atomic fluorescence spectrometry (ED-GC-AFS) is associated with an intimate problem of water moisture accumulation introduced in the ethylation step, which enters the detection system and cause a spectroscopic interference. With a simple modification on the GC-AFS system, this problem was eliminated and the analytical quality of the measurements was significantly improved. The presence of dissolved sulfide in samples can also cause serious chemical interference in the ethylation step resulting in lower or total loss of the MeHg signal. It was found that a masking system of CuSO(4)-Na(2)C(2)O(4) was able to eliminate this interference. With this system, the accurate determination of trace amount of MeHg in high dissolved sulfide containing samples was achieved. Satisfactory analytical results were obtained with the certified reference sediment IAEA405, sulfate reducing bacteria culture and sulfide containing water samples. The limit of detection and quantitation of this masking system is 0.01 and 0.04ngL(-1) respectively. Other factors affecting ethylation are also discussed.
authors.affiliation: Laurentian University, Ramsey Lake Road, Sudbury, P3E 2C6, Canada.
authors.forename: Dan-Yi
authors.initials: DY
authors.lastname: Yang
authors.forename: Hoang-Yen Thi
authors.initials: HY
authors.lastname: Truong
authors.forename: Yu-Wei
authors.initials: YW
authors.lastname: Chen
authors.forename: Nelson
authors.initials: N
authors.lastname: Belzile
mesh_terms: D018929:Cell Culture Techniques; D002849:Chromatography, Gas / Q000379:methods*; D019327:Copper Sulfate / Q000737:chemistry; D045285:Desulfovibrio desulfuricans / Q000737:chemistry; D004784:Environmental Monitoring / Q000379:methods*; D019015:Geologic Sediments / Q000032:analysis; D008767:Methylmercury Compounds / Q000032:analysis*; D010070:Oxalates / Q000737:chemistry; D012015:Reference Standards; D012680:Sensitivity and Specificity; D013050:Spectrometry, Fluorescence / Q000379:methods; D013440:Sulfides / Q000737:chemistry*; D013696:Temperature; D014867:Water / Q000032:analysis
chemical_list: D008767:Methylmercury Compounds; D010070:Oxalates; D013440:Sulfides; D014867:Water; D019327:Copper Sulfate