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

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 NaBH4 in presence of HCl. Hg0 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 NaBH4 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

Determinação espectrofotométrica de cloreto em cimento após preparo de amostra por piroidrólise

A method based on pyrohydrolysis was proposed for cement sample preparation and further chloride determination by spectrophotometry using flow injection analysis. Analytical parameters were evaluated and, under the selected conditions, the calibration curve was linear in the range of 0.2 to 10.0 µg mL-1 with r2 = 0.998. The limit of detection was5 µg g-1 of chloride and the relative standard deviation was less than 7%. The proposed pyrohydrolysis method is relatively simple and can be used for sample preparation for further spectrophotometric determination of low concentrations of chloride in cement

Agricultural contamination: Effect of copper excess on physiological parameters of potato genotypes and food chain security

Areas with a history of cupric fungicide application accumulate copper (Cu), which may be toxic to plants and might result in food chain contamination. This work aimed to study the effects of Cu contaminated vineyard soils (2.2, 5, 36.3, 67, 95.7, 270.5 and 320.70 mg Cu kg-1 soil) on potato physiology and it´s potential risk to human health, during the fall and spring growing seasons. The increase of Cu concentration in leaves was dependent on external Cu concentrations and development stage of the leaves. There were genotypic differences for both growth and biochemical parameters including high accumulation of Cu in tubers among the genotypes. Therefore, Cu stress triggered a defense mechanism against oxidative stress in potato plants; and the magnitude of Cu stress was depended on the genotype and the plant physiological status. In addition, these results provide evidence that potato antioxidants are not sufficient to prevent biological damage caused by Cu toxicity, and that popato cultivation in areas with high Cu levels is not recommended due to low production and potential risk to human health

Hair analysis : a review on the procedures for the determination of Trace elements and applications

Aspects related to the quality of human hair analysis are presented, such as sample collection, sample preparation, determination of trace elements and application examples. Also the hair morphology, the importance of this analysis and its uses and meanings are discussed

Hair analysis : a review on the procedures for the determination of Trace elements and applications

Aspects related to the quality of human hair analysis are presented, such as sample collection, sample preparation, determination of trace elements and application examples. Also the hair morphology, the importance of this analysis and its uses and meanings are discussed