Slurry Sampling Electrothermal Atomic Absorption Spectrometric Determination of Lead, Cadmium and Manganese in Human Hair Samples Using Rapid Atomizer Programs† PILAR BERMEJO-BARRERA*, ANTONIO MOREDA-PIN ˜ EIRO, JORGE MOREDA-PIN ˜ EIRO AND ADELA BERMEJO-BARRERA Department of Analytical Chemistry, Nutrition andBromatology, Faculty of Chemistry, University of Santiago de Compostela, Avenida de las Ciencias, s/n E-15706 Santiago de Compostela, Spain Rapid methods for the determination of lead, cadmium and such as the atmosphere, dirt, dust, sweat, cosmetic and pharma- ceutical preparations occur. In addition, the concentration of manganese in human scalp hair by ETAAS using rapid atomizer programs and deuterium arc background correction a metal varies along the length of a hair from the root to tip, and for lead, a slight increase towards the tip has been have been developed. Samples were powdered by means of a zirconia vibrating ball mill over a period of 20 min (mean reported.6 Another drawback that usually occurs when a metal determination is performed, is the fact that the concentration particle size less than 1 mm). Then 0.1 g of the powder was suspended in a few ml of water and diluted to 25 ml. An of a certain metal in hair is dependent on the sampling site.7 To overcome problems related to contamination, an adequate optimum drying temperature of 250 °C was found for lead, cadmium and manganese. Optimum atomization temperatures hair washing stage prior to measurement is needed. In this context, the concentration of some metals, such as lead, has of 2200 and 1900 °C were found for cadmium and manganese, and for lead, respectively. The program cycles were 38 s for been demonstrated to be dependent on the washing procedure carried out,4 the most appropriate being the washing process cadmium and lead, and 37 s for manganese. Glycerol, at an optimum concentration of 0.4% m/v, was used as a stabilizing recommended by the IAEA.8 To overcome the problems associated with variation along the length of a hair and the agent. Simple aqueous calibration was used for all analytes. The limits of detection were 0.03, 0.05 and 0.04 mg kg-1 for sampling site, it has been demonstrated that the segments of hair follicles that are still biologically active are the most cadmium, lead and manganese, respectively. Accuracy was studied by analysing CRM 397 human hair, and the cadmium representative and should be collected from the occipital region of the head, as close as possible to the scalp.7 and lead levels were found to be in accordance with the certified accuracy values. The levels of metals obtained were in However, as hair is a solid material, an initial sample decomposition step is necessary, and various procedures such agreement with those previously reported for healthy people in Europe, i.e., less than 3.0 and 0.3 mg kg-1 for lead and as acid4,7,9–11 or alkali12 digestions have been described. In order to avoid problems introduced by this sample pre- cadmium, respectively. treatment, such as contamination or loss of volatile elements, Keywords: Electrothermal atomic absorption spectrometry; the slurry sampling technique appears to be a suitable alterna- slurry sampling; cadmium; lead; manganese; human hair tive. This approach has been applied successfully with ETAAS for the determination of several metallic elements in a wide range of biological and environmental samples.13 Lead, cadmium and manganese are classified as prevalent toxic metals which tend to be concentrated in environmental systems In the present paper, methods are proposed for the determi- nation of lead, cadmium and manganese in slurries of scalp and humans. Absorption from the air in the local environment and intake from the diet are the major sources of human hair using atomizer programs without a charring stage. The omission of the charring stage offers a rapid ETAAS determi- exposure. Although toxic metal accumulation in humans is dependent upon the nature of the toxic metal compound and nation, as the program cycles have been shortened.14 This fact, in conjunction with the rapid slurry preparation procedure, the environmental metal load, lead has been demonstrated to be accumulated in bone and in some soft tissues, such as the makes the proposed methods faster than those reported previously for determination of metals in hair.4,7,9–12 liver, kidneys and brain, while cadmium is known to damage organs such as the kidneys, liver and lungs.1 Moreover, although excess of manganese is a relatively rare phenomenon, some manganese poisoning has been reported and it has been EXPERIMENTAL established that the manganese is assimilated by the liver, Apparatus heart and skeleton.2 Hair has been shown to be a major vehicle for the excretion All absorbance measurements were performed on a Perkin- of toxic metals, 3 and thus hair analysis has been used as an Elmer (U ¨ berlingen, Germany) 1100B atomic absorption spec- appropriate technique in forensic science4 and as an index of trometer equipped with a deuterium lamp for background environmental exposure.5 Because the hair is a vehicle for correction, a Perkin-Elmer HGA-400 graphite furnace and a excretion of metals, the concentration of toxic metals in hair Perkin-Elmer AS-40 autosampler. Spectrometric operating is up to ten-fold higher than the levels found in blood or urine conditions are given in Table 1. A Laser Coulter Series LS100, samples.3,4 Nevertheless, external contamination from sources Fraunhofer Optical Model particle sizer (Coulter Electronics, Hialeah, FL, USA) was used to obtain the particle size distributions. A vibrating ball mill (Retsch, Haan, Germany), † Presented at the Eighth Biennial National Atomic Spectroscopy Symposium (BNASS), Norwich, UK, July 17–19, 1996. equipped with zirconia cups and zirconia balls (7 mm Journal of Analytical Atomic Spectrometry, March 1997, Vol. 12 (301–306) 301