Determination of total mercury in scalp hair of humans by gold amalgamation cold vapour atomic absorption spectrometry

Bruhn, C. G.; Rodríguez, Aldo; Barrios, Carlos Angulo; Jaramillo, Víctor Hugo González; Becerra, José; González, Urcesino; Gras, N.; Reyes, O C; Salud, Seremi

doi:10.1039/ja9940900535

Cited by 23 publications

(14 citation statements)

References 22 publications

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“…N°CRM-OT, Lot # 691126, High Purity Standards, Charleston, SC, USA). Liquid nitrogen (AGA, Concepcion, Chile) was used to freeze the hair samples within the PTFE flasks before comminution in the micro-dismembrator [23].…”

Section: Reagents Materials and Samplesmentioning

confidence: 99%

“…Human hair samples of six volunteers, males and non-smokers (three workers under different exposure levels to arsenic in a glass factory and three unexposed workers of the University staff), were collected, cleaned, and prepared in powdered form as described elsewhere [23]. The clam sample used in the study of thermal conditions was homogenized, freeze-dried, powdered clam ("almeja", Semelle sólida) prepared from a fresh sample collected in a natural bank of the Southern Chilean coast [24].…”

Section: Reagents Materials and Samplesmentioning

confidence: 99%

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Chemical modifiers in arsenic determination in biological materials by tungsten coil electrothermal atomic absorption spectrometry

Bruhn

Huerta

Neira

2004

Analytical and Bioanalytical Chemistry

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Palladium, iridium, and rhodium are evaluated as possible chemical modifiers in the determination of As in digest solutions of biological materials (human hair and clam) by tungsten coil electrothermal atomic absorption spectrophotometry (TCA-AAS). The modifier in solution was applied onto the coil and thermally pre-reduced; the pre-reduction conditions, the amount of modifier, and the thermal program were optimized. Palladium was not satisfactory, whereas Ir and Rh were effective modifiers and rendered better relative sensitivity for As by a factor of 1.4 and 1.9, respectively compared to the case without modifier. Upon optimization of thermal conditions for As in pre-reduced Ir (2.0 microg) and Rh (2.0 microg) modifiers and in the digest solutions of the study matrices, Rh (2.0 microg) was more effective modifier and was selected as such. The mean within-day repeatability was 2.8% in consecutive measurements (25-100 microg L(-1)) (3 cycles, each of n=6) and confirmed good short-term stability of the absorbance measurements. The mean reproducibility was 4.4% (n=20 in a 3-day period) and the detection limit (3 sigmablank/slope) was 29 pg (n=15). The useful coil lifetime in Rh modifier was extended to 300-400 firings. Validation was by determination of As in the certified reference material (CRM) of "Oyster tissue" solution with a percentage relative error (Erel%) of 2% and percentage relative standard deviation (RSD%) of 3% (n=4), and by analytical recovery of As spiked in CRM of human hair [94 +/- 8% (n=4)]. The methodology is simple, fast (sample readout frequency 21 h(-1)), reliable, of low cost, and was applied to the determination of As in hair samples of exposed and unexposed workers.

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Section: Reagents Materials and Samplesmentioning

confidence: 99%

Section: Reagents Materials and Samplesmentioning

confidence: 99%

Chemical modifiers in arsenic determination in biological materials by tungsten coil electrothermal atomic absorption spectrometry

Bruhn

Huerta

Neira

2004

Analytical and Bioanalytical Chemistry

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“…Other biological materials were digested in concentrated HNO3 in PTFE bombs or in HNO3 : HCIO4 mixture in sealed Pyrex ampoules, as described elsewhere (30). The acid mixture was used to enhance oxidation of organomercury compounds in such highly organic matrices.…”

Section: Cvaasmentioning

confidence: 99%

Total Mercury and Methylmercury Levels in Scalp Hair and Blood of Pregnant Women Residents of Fishing Villages in the Eighth Region of Chile

Bruhn¹,

Rodríguez²,

Barrios³

et al. 1997

ACS Symposium Series

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The extent of environmental exposure to mercury through the diet (i.e., by consumption of fish and seafood), of a population group having higher than average fish and seafood consumption was assessed between 1991 and 1994 in pregnant women (PW) and nursing women (NW) residing in selected fishing villages (FVs) along the coastal zone of the Eighth Region of Chile. The control population was an equivalent group with negligible seafood consumption. The samples were scalp hair collected from the occipital region, and blood obtained by venipuncture. Total mercury (Hg-T) levels were determined by cold vapor atomic absorption spectrometry (CVAAS) in all samples, and in 20% of them by instrumental neutron activation analysis (INAA) as a reference method. Methylmercury (Me-Hg) was determined by gas chromatography with electron capture detector (GC-ECD) in hair samples of the 1994 study, after its selective isolation from human hair by volatilization in a microdiffusion cell. Significant efforts were made to validate the analytical methodology for Hg-T and Me-Hg determination in human hair, and for Hg-T determination in blood. Multiple comparison tests confirmed significant differences in Hg-T content between PW and NW in each FV and in the control group, with higher concentrations in at least five FVs which were selected for further in depth studies. A new survey was performed in the selected five FVs and in the control group in 1994, including

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“…Several methods have been proposed for pre-concentration of Hg/matrix separation, such as amalgamation 23,24 or sorption of complexes of Hg by resins placed inside columns. 17,18,[25][26][27] Stable complexes of Hg are produced by reaction of Hg inorg with anions, such as SCN -, CH 3 COO -, I -, Br -and Cl -.…”

Section: Introductionmentioning

confidence: 99%

Mercury speciation in urban landfill leachate by cold vapor generation atomic absorption spectrometry using ion exchange and amalgamation

Flores¹,

Paniz²,

Flores³

et al. 2009

J. Braz. Chem. Soc.

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Foi desenvolvido um sistema em linha para a especiação de Hg orgânico (Hg org ) e Hg inorgânico (Hg inorg ) em chorume. Clorocomplexos produzidos a partir do Hg inorg são separados em uma coluna trocadora de ânions. O Hg retido na coluna é eluído com NaBH 4 na presença de HCl. O Hg 0 produzido é medido por espectrometria de absorção atômica com geração de vapor frio (CV AAS). O Hg org , que não fica retido na coluna, é misturado com NaBH 4 produzindo espécies voláteis de Hg, as quais são amalgamadas numa rede de Au/Pt. O Hg é removido desta coluna por aquecimento a 600 °C e medido por CV AAS. Para a especiação de Hg inorg e Hg org em chorume, as amostras são centrifugadas, filtradas e tratadas com HCl. Os limites de detecção (3 s) são 9 e 12 ng L -1 de Hg para Hg inorg e Hg org , respectivamente. A freqüência de análise é 22 h -1 .This work deals with on line speciation of organic Hg (Hg org ) and inorganic Hg (Hg inorg ) in urban landfill leachate. Chlorocomplexes of Hg inorg are produced in HCl medium and retained on an anion exchange column. The retained Hg is eluted with NaBH 4 in presence of HCl. Hg 0 is produced and then measured by cold vapor atomic absorption spectrometry (CV AAS). Hg org does not interact with the resin and is mixed with NaBH 4 at the exit of the column producing volatile species of Hg that are then amalgamated by a gauze of Au/Pt. Mercury is removed from the gauze by heating to 600 °C and subsequently measured by CV AAS. For Hg inorg and Hg org speciation in urban landfill leachate, the samples are centrifuged, filtered and treated with HCl. The detection limits (3 s) of Hg inorg and Hg org are 9 and 12 ng L -1 of Hg, respectively. The analysis frequency is 22 h -1 .Keywords: mercury speciation, landfill leachate; flow analysis, ion exchange, amalgamation, CVG AAS IntroductionIn several countries, the urban waste is usually discarded in landfills, producing toxic leachate and toxic gases. The rainwater percolation through the residues and its inherent aqueous fraction comprise the leachate, which is characterized by high concentration of organic matter, salts, suspended particles and toxic elements. 1,2 Mercury is one of the elements often present in landfill leachate and become an environmental problem. 3 Inorganic Hg (Hg inorg ), mainly as Hg 0 and Hg 2+ , is generally disposed in urban landfills, 4 where it can associate to colloidal particles, complex with organic matter and/or bind to sulfides. 5 Under anaerobic conditions a significant fraction of Hg is transformed into more toxic species. Inorganic mercury may be transformed to other toxic species in landfill, such as methyl mercury, ethyl mercury and phenyl mercury. 6 However, the concentrations of ethyl mercury and phenyl mercury are very low and usually not detected by conventional techniques. Despite the possibility of formation of many organic and inorganic compounds of Hg in the environment, methyl mercury is usually the most abundant Hg org species found in environmental samples, [7][8][9] whereas Hg 2+ is the main Hg ino...

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Determination of total mercury in scalp hair of humans by gold amalgamation cold vapour atomic absorption spectrometry

Cited by 23 publications

References 22 publications

Chemical modifiers in arsenic determination in biological materials by tungsten coil electrothermal atomic absorption spectrometry

Chemical modifiers in arsenic determination in biological materials by tungsten coil electrothermal atomic absorption spectrometry

Total Mercury and Methylmercury Levels in Scalp Hair and Blood of Pregnant Women Residents of Fishing Villages in the Eighth Region of Chile

Mercury speciation in urban landfill leachate by cold vapor generation atomic absorption spectrometry using ion exchange and amalgamation

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