The Direct Determination of Mercury in Fair by Atomic Absorption Spectroscopy at the 184.9 nm Resonance Line

Abstract

Abstract The direct determination of total mercury levels in human scalp hair was accomplished by atomic absorption spectroscopy at 184.9 nm through the use of a unique carbon bed atomizer. The Robinson quartz T atomizer permitted the analysis of solid hair samples, 1-cm or less in length, with no sample pretreatmant. This direct analysis eliminated both loss of volatile mercury compounds during pretreatment and contamination of the sample by added reagents. The accuracy of the determination was improved thereby. Use of the 184.9 nm line in the vacuum ultraviolet region provided increased sensitivity over the more commonly employed 253.7 nm line. A 1 % absorption signal was generated by 1.5 × 10−11 g Hg. This sensitivity allowed determination of variations as small as 0.1 ppm in mercury concentration along the hair shaft. In general, distal mercury levels were found to be higher than proximal mercury levels. Washing hair with distilled deionized water or acetone had no significant effect on proximal mercury concentration. Hair was shown to absorb elemental mercury vapor from air saturated with mercury vapor. Proximal mercury levels increased from 0.3 ng Hg/cm hair to 9.8 ng Hg/cm hair over a 7-day exposure period.