Reoval of exogenously boud elements from human hair by various washing procedures and determination by inductively coupled plasma mass spectrometry

摘要

A review of the literature shows that a variety of washing procedures to remove external contaminationfrom hair have been proposed, but as yet no standardised procedures are available. In this study, methods for the pre-treatment and determination of antimony, arsenic, cadmium, chromium, lead mercury and selenium in buman hair by inductively coupled plasma mass spectrometry (ICP-MS) are developed. Investigations of various washing procedures to remove external contaminants show that in unexposed hair samples cadmium, lead and mercury are significantly removed from hair using a 0.1 M HCl wash, with 87, 73 and 5%, respectively being washed-off. The removal of antimony, arsenic and chromium from unexposed hair is, however,more efficient with 1% (v/v) sodium lauryl suphate (SLS), with 43, 40 and 13% of each element, respectively being washed-off. Selenium is not removed from the hair by any of the washing methods studied. For the digestion of hair samples a digestion mixture of nitric acid and hydrogen eroxide is used. Experiments with simulated sweat spiked with each of these elements show that exogenously bound chromium, cadmium and lead are removed after washing with 0.1 M HCl. In contrast, antimony, arsenic, selenium and mercury irreversibly bind and, thus, are not removed with any of the washing solutions investigated. This work also compares hair levels of these elements in an unexposed and exposed group using the method developed.