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Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) was applied for the determination of Br and I in hair strands of human individuals under treatment with synthetic thyroid hormones. Quantification relied on the use of Br- and I-spiked human hair strands prepared in-house as matrix-matched external calibration standards. The results obtained via LA-ICP-MS agreed with the corresponding Br and I concentrations as determined via pneumatic nebulization-ICP-MS after digestion via microwave-induced combustion. The spatial distributions of Br and I in the spiked hair standards were evaluated by spatially resolved LA-ICP-MS analysis and a homogeneous distribution was established upon scanning longitudinally along the hair strands and across the cross-section. Twenty-five human hair strands from volunteers were analyzed by LA-ICP-MS (7 individuals with hypothyroidism under treatment with synthetic thyroid hormones and 18 individuals considered healthy), and those from subjects under treatment with synthetic thyroid hormones presented a higher I concentration than those from subjects considered healthy. Limits of detection were 0.36 μg g−1 for Br and 0.14 μg g−1 for I, allowing trace level determination in human hair. [ABSTRACT FROM AUTHOR]

In this work, the use of complexing acids (HF and HCl) combined with HNO3 was carefully evaluated for the digestion of several types of lipsticks and further Cd and Pb determination by inductively coupled plasma mass spectrometry (ICP-MS). Creamy, opaque and shimmering lipsticks were digested using HNO3 (6 mL) or a mixture containing HNO3 (6 mL) plus HCl (0.5 or 2 mL) or HNO3 (6 mL) plus HF (2 mL). The results indicate that complexing acids are not required for the subsequent determination of Cd in all types of lipsticks evaluated. On the other hand, complexing acids were essential for ensuring quantitative results for Pb in shimmering lipstick. Thus, by using HNO3 combined with only 0.5 mL of HCl, it was possible to obtain quantitative results for Pb and Cd in lipsticks. Under these conditions, recoveries for Cd and Pb were between 95 and 103%. No statistical difference was observed between the results obtained using the proposed method (HNO3/HCl) and those obtained using HNO3/HF, where a complete dissolution of the lipsticks' inorganic fraction occurred. Moreover, by using HCl, HF was avoided and solutions more compatible with ICP-MS analysis were obtained. The limits of detection for Cd and Pb were 3 and 77 ng g−1, respectively. This method was applied for a variety of lipsticks, and the concentration of Cd and Pb ranged from ＜3 to 31 ng g−1 and 271 to 2250 ng g−1, respectively. [ABSTRACT FROM AUTHOR]