Determination of zinc and copper in human hair by slurry sampling employing sequential multi-element flame atomic absorption spectrometry

Visual detection of trace copper ions based on copper-catalyzed reaction of ascorbic acid with oxygen

A visual detection method for trace Cu(2+) in aqueous solutions using triangular silver nanoplates (abbreviated as TAgNPs) as the probe was developed. The method is based on that TAgNPs could be corroded in sodium thiosulfate (Na2S2O3) solutions. The absorption spectrum of TAgNPs solution changed when it is corroded by Na2S2O3. The reaction of oxygen with ascorbic acid (Vc) in the presence of a low concentration of Cu(2+) generates hydrogen peroxide that reacts with Na2S2O3, which leads the concentration of Na2S2O3 in the solution to be decreased. Therefore, the reaction between TAgNPs and the reacted mixture of Na2S2O3/Vc/Cu(2+) was prevented efficiently. When the Na2S2O3 concentration and reaction time are constant, the decrease in the concentration of Na2S2O3 is directly proportional to the Cu(2+) concentration. Thus, morphology, color, and maximum absorption wavelength of TAgNPs changed with the change of Cu(2+) concentration. The changed maximum absorption wavelength of TAgNPs (Δλ) is proportional to Cu(2+) concentration in the range from 7.5×10(-9) to 5.0×10(-7) M with a correlation coefficient of r=0.9956. Moreover, color change of TAgNP solution was observed clearly over a Cu(2+) concentration range from 7.5×10(-8) to 5.0×10(-7) M. This method has been used to detect the Cu(2+) content of a human hair sample, and the result is in agreement with that obtained by the atomic absorption spectroscopy (AAS) method.

Chromium, zinc and magnesium concentrations in the pubic hair of obese and overweight women

The study addressed chromium, zinc and magnesium concentrations in the pubic hair of obese and overweight women. It was carried out on hair collected from 85 women at the age of 16-80 living in the Podkarpackie Voivodeship (southern Poland). The experimental and control groups consisted of 39 and 46 females, respectively. The pubic hair was prepared under a procedure established by the International Atomic Energy Agency, followed by wet digestion in a microwave oven. The concentration of the metals in the pubic hair and reference material was assayed with the flame (Mg, Zn) and flameless (Cr) atomic absorption spectrometry. The pubic hair of overweight and obese women from the experimental group revealed significantly higher chromium and magnesium concentrations and significantly lower concentrations of zinc than in the control group. An increase in BMI brought about an increase in chromium and magnesium concentrations while zinc concentration decreased with increasing BMI. The disturbances in the mineral balance of overweight and obese women were also demonstrated by significantly different ratios of the elements compared with the control group.

Old and New Flavors of Flame (Furnace) Atomic Absorption Spectrometry

This paper presents some recent applications of Flame Atomic Absorption Spectrometry (FAAS) to different matrices and samples. The time window selected was from 2006 up to March, 2011, and several aspects related to food, biological fluids, environmental, and technological samples analyses were reported and discussed. In addition, the chemometrics application for FAAS methods development was also taken into account, as well as the use of metal tube atomizers in air/acetylene flame. Preconcentration methods coupled to FAAS were discussed, and several approaches related to speciation, flotation, ionic liquids, among others were discussed. This paper can be interesting for researchers and FAAS users in order to see the state of the art of this technique.

Hair analysis as a biomonitor for toxicology, disease and health status

Hair analysis receives a large amount of academic and commercial interest for wide-ranging applications. However, in many instances, especially for elemental or 'mineral' analysis, the degree of success of analytical interpretation has been quite minimal with respect to the extent of such endeavors. In this critical review we address the questions surrounding hair analysis with specific intent of discovering what hair concentrations can actually relate to in a biogenic sense. This is done from a chemistry perspective to explain why and how elements are incorporated into hair and their meaning. This includes an overview of variables attributed to altering hair concentrations, such as age, gender, melanin content, and other less reported factors. Hair elemental concentrations are reviewed with regard to morbidity, with specific examples of disease related effects summarized. The application of hair analysis for epidemiology and etiology studies is enforced. A section is dedicated specifically to the area of population studies with regards to mercury, which highlights how endogenous and exogenous incorporation relies on species dependant metabolism and metabolic products. Many of the considerations are relevant to other areas of interest in hair analysis, such as for drug and isotopic analysis. Inclusion of a table of elemental concentrations in hair should act as a valuable reference (298 references).

A preconcentration system for determination of copper and nickel in water and food samples employing flame atomic absorption spectrometry

A separation/preconcentration procedure using solid phase extraction has been proposed for the flame atomic absorption spectrometric determination of copper and nickel at trace level in food samples. The solid phase is Dowex Optipore SD-2 resin contained on a minicolumn, where analyte ions are sorbed as 5-methyl-4-(2-thiazolylazo) resorcinol chelates. After elution using 1 mol L(-1) nitric acid solution, the analytes are determinate employing flame atomic absorption spectrometry. The optimization step was performed using a full two-level factorial design and the variables studied were: pH, reagent concentration (RC) and amount of resin on the column (AR). Under the experimental conditions established in the optimization step, the procedure allows the determination of copper and nickel with limit of detection of 1.03 and 1.90 microg L(-1), respectively and precision of 7 and 8%, for concentrations of copper and nickel of 200 microg L(-1). The effect of matrix ions was also evaluated. The accuracy was confirmed by analyzing of the followings certified reference materials: NIST SRM 1515 Apple leaves and GBW 07603 Aquatic and Terrestrial Biological Products. The developed method was successfully applied for the determination of copper and nickel in real samples including human hair, chicken meat, black tea and canned fish.