Nickel Content in Human Internal Organs.

With the growing interest in new applications of metals in modern technologies, an increase in their concentration in the environment can be observed, which, in consequence, may constitute a hazard to human health. That is why it is of a great importance to establish "reference" levels of particular elements (essential or toxic) in human biological samples.The aim of this paper was to determine nickel in autopsy tissues of non-occupationally exposed subjects in Southern Poland (n = 60). Measurements were performed by means of electrothermal atomic absorption spectrometry after microwave-assisted acid digestion according to previously optimized and validated procedure. The results obtained indicate that data cover the wide range of concentrations and generally are consistent with other published findings. Nickel levels in the brain, stomach, liver, kidneys, lungs and heart (wet weight) were between 2.15-79.4 ng/g, 0.5-44.2 ng/g,7.85-519 ng/g, 12.8-725 ng/g, 8.47-333 ng/g and 2.3-97.7 ng/g, respectively. Females had generally lower levels of nickel in tissues than males (statistically significant relationships were found for the liver, kidneys and lungs), and median nickel concentrations in all studied material within all age groups had very similar values, with the exception of stomach.

Chromium in Postmortem Material.

Recently, considerable attention has been paid to the negative effects caused by the presence and constant increase in concentration of heavy metals in the environment, as well as to the determination of their content in human biological samples. In this paper, the concentration of chromium in samples of blood and internal organs collected at autopsy from 21 female and 39 male non-occupationally exposed subjects is presented. Elemental analysis was carried out by an electrothermal atomic absorption spectrometer after microwave-assisted acid digestion. Reference ranges of chromium in the blood, brain, stomach, liver, kidneys, lungs, and heart (wet weight) in the population of Southern Poland were found to be 0.11-16.4 ng/mL, 4.7-136 ng/g, 6.1-76.4 ng/g, 11-506 ng/g, 2.9-298 ng/g, 13-798 ng/g, and 3.6-320 ng/g, respectively.

An automated continuous homogeneous microextraction for the determination of selenium and arsenic by hydride generation atomic fluorescence spectrometry.

An automated continuous homogeneous microextraction approach based on a flow system has been developed and coupled with a hydride generation atomic fluorescence spectrometry system (HG-AFS). The developed approach was applied for the determination of trace arsenic and selenium in environmental water and liver samples. The nonanoic acid was investigated as a switchable hydrophilicity solvent (SHS) for homogeneous microextraction of As(III) and Se(IV) complexes with pyrrolidinedithiocarbamate (PDC). The procedure involved on-line mixing ammonium PDC (aqueous phase), sodium nonanoate (aqueous phase) and acid sample solution resulting in the formation of SHS (nonanoic acid) dispersed into the acid aqueous phase. By this continuous process, analytes complexes with PDC were formed and extracted into the fine SHS droplets followed by retention into a monolithic column packed with block of porous PTFE. Finally, the retained complexes were eluted with NaOH solution and delivered to the HG-AFS system. The limits of detection, calculated from a blank test based on 3σ, were 0.01µgL-1 for both analytes.

Optimization and Validation of an ETAAS Method for the Determination of Nickel in Postmortem Material.

In this article, optimization and validation of a procedure for the determination of total nickel in wet digested samples of human body tissues (internal organs) for forensic toxicological purposes are presented. Four experimental setups of the electrothermal atomic absorption spectrometry (ETAAS) using a Solaar MQZe (Thermo Electron Co.) were compared, using the following (i) no modifier, (ii) magnesium nitrate, (iii) palladium nitrate and (iv) magnesium nitrate and ammonium dihydrogen phosphate mixture as chemical modifiers. It was ascertained that the ETAAS without any modifier with 1,300/2,400°C as the pyrolysis and atomization temperatures, respectively, can be used to determine total nickel at reference levels in biological materials as well as its levels found in chronic or acute poisonings. The method developed was validated, obtaining a linear range of calibration from 0.76 to 15.0 µg/L, limit of detection at 0.23 µg/L, limit of quantification at 0.76 µg/L, precision (as relative standard deviation) up to 10% and accuracy of 97.1% for the analysis of certified material (SRM 1577c Bovine Liver) and within a range from 99.2 to 109.9% for the recovery of fortified liver samples.

Optimization and validation of a procedure for the determination of total chromium in postmortem material by ETAAS.

A study was conducted to optimize and validate a procedure for the determination of total chromium in wet digested samples of human blood and body tissues for forensic toxicological purposes. Five experimental setups of electrothermal atomic absorption spectrometry (ETAAS) using a Solaar MQZe (Thermo Electron Co.) were compared, using the following: (i) no modifier, (ii) magnesium nitrate, (iii) palladium nitrate, (iv) magnesium and palladium nitrate mixture and (v) palladium nitrate and ammonium dihydrogen phosphate mixture as chemical modifiers. Furthermore, for the mineralization process in the Ethos 1 microwave system (Milestone), it was found that the temperature program suggested by the producer should be improved, thus, four experimental setups are presented. Finally, the whole procedure was validated, obtaining a linear range of calibration from 0.22 to 12.0 µg/L, limit of detection at 0.07 µg/L, limit of quantification at 0.22 µg/L, precision (as relative standard deviation) up to 6%, and accuracy of 98.4-104.4% for the analysis of certified material (ClinChek Whole Blood Control Level III, SRM Whole Blood Level II and III and SRM 1577c Bovine Liver) and within a range from 84.5 to 103.2% for the recovery of spiked samples. It was ascertained that modified wet digestion, followed by ETAAS with magnesium nitrate as a modifier (5 µg) with 1,400/2,500°C as the pyrolysis and atomization temperatures, respectively, can be used to determine chromium at reference levels in biological materials (blood and internal organs) and levels found in chronic or acute poisonings with chromium compounds.