Ricerc@Sapienza

The aim of the study was to develop and validate a rapid method for the analysis of the total Hg concentration in human hair, specifically, Eritrean hair. For total Hg determination, the cold vapour generation atomic fluorescence spectrometry (CV-AFS) technique was used, and the results were compared with those of the more frequently used advanced mercury analyser (AMA). Samples were prepared by washing the hair and collecting two samples; the first was used for the direct analysis of Hg by AMA and the second was digested for Hg determination by CV-AFS. The results of field hair sample analysis indicate that the two data sets were fully comparable (median: AMA, 0.11 mg kg-1; CV-AFS, 0.12 mg kg-1) and were not statistically different (Mann–Whitney test, p-value = 0.944). The two techniques showed results with good coefficients of determination (R2 = 0.98) despite the different operating ranges. The AMA and CV-AFS methods were validated using a certified reference hair sample, yielding, respectively, trueness biases of 7.4% and 7.2%, intra-day repeatabilities (relative standard deviation (RSD), %) of 3.2% and 6.0%, inter-day reproducibilities (RSD, %) of 5.3% and 8.2%, and expanded standard measurement uncertainties of 8.9% and 17%, respectively. Analyses of blank measurements by AMA and CV-AFS yielded a detection limit of 0.0004 and 0.004 mg kg-1 of Hg for 5 and 20 mg samples of human hair, respectively. Both techniques are simple, easy to use, and relatively inexpensive, and the method validation parameters indicate sensitivity, precision, and reliability. In conclusion, the use of AMA should be considered over CV-AFS in hair analysis to reduce sample handling and, consequently, lower the risk of contamination, use fewer samples, and allow more economical analyses. In contrast, CV-AFS using optimised fast digestion in an open vessel heated in a water bath instead of AMA allows short analysis times and automation, thus allowing high sample throughput for routine analysis and human biomonitoring studies.