Determination of total arsenic concentrations in nails by inductively coupled plasma mass spectrometry

Abstract

The analysis of trace elements in biological samples will extend our understanding of the impact that environmental exposure to these elements has on human health. Measuring arsenic content in nails has proven useful in studies evaluating the chronic body burden of arsenic. In this study, we developed methodology with inductively coupled plasma-mass spectrometry (ICP-MS) for the determination of total arsenic in nails. We assessed the utility of the washing procedures for removing surface contamination. Four types of preanalysis treatments (water bath, sonication, water bath plus sonication, and control) after sample decomposition by nitric acid were compared to evaluate the digestion efficiencies. In addition, we studied the stability of the solution over 1 wk and the effect of acidity on the arsenic signal. Arsenic content in the digested solution was analyzed by using Ar-N2 plasma with Te as the internal standard. The results suggest that washing once with 1% Triton X-100 for 20 min for cleaning nail samples prior to ICP-MS analysis is satisfactory. Repeated measurement analysis of variance revealed that there was no significant difference among the various sample preparation techniques. Moreover, the measurements were reproducible within 1 wk, and acidity seemed to have no substantial influence on the arsenic signal. A limit of detection (on the basis of three times the standard deviation of the blank measurement) of 7 ng As/g toenail was achieved with this system, and arsenic recoveries from reference materials (human hair and nails) were in good agreement (95-106% recovery) with the certified/reference values of the standard reference materials. ICP-MS offers high accuracy and precision, as well as high-throughput capacity in the analysis of total arsenic in nail samples.

Maternal Arsenic Exposure and Impaired Glucose Tolerance during Pregnancy

“…The weight required for the hair sample analysis is 0.125 g, which corresponds to about 50 strands of hair or the thickness of a pencil. Total hair arsenic concentration was meas ured using previously published methods (Chen et al 1999). The limit of detection for hair arsenic was 0.2 ng/g.…”

Comparison of arsenic levels in fingernails with urinary As species as biomarkers of arsenic exposure in residents living close to a coal-burning power plant in Prievidza District, Slovakia

“…The nails were kept in the envelopes until analysis in 2002. The washing procedure was based on the methods described by Wilhelm et al (1991) and Chen et al (1999). First, the fingernail samples were washed with Triton-X 100 (2%; Merck, Darmstadt, Germany) in an ultrasonic bath for 20 min.…”

Estimation of arsenic in nail using silver diethyldithiocarbamate method

“…Inter-day variability of arsenic measurements is not significant across a week after acid digestion (Chen et al, 1999).…”

“…Lastly, use water to remove the acetone and loosen or dissolve surface contaminants (Karagas et al, 1996). Washing with Triton X-100 (2%) for 20 min may reduces the amount of arsenic in nail (Chen et al, 1999). Excessive exposure of nail to acetone should be avoided.…”

“…Estimation of arsenic in nail can be done using spectrophotometer, atomic absorption spectrometer with hydride generator (AAS-HG), High performance liquid chromatography with hydride generation with atomic fluorescence spectrometer (HPLC-HG-AFS), inductively coupled plasma-mass spectrometry (ICP-MS) (Chen et al, 1999), proton particle-induced X-ray emission and neutron activation analysis. Among these methods spectrophotometric method using silver diethyldithiocarbamate (SDDC) is still an effective, widely used and cheapest method.…”