A fast method for the determination of 16 elements in hair samples by inductively coupled plasma mass spectrometry (ICP-MS) with tetramethylammonium hydroxide solubilization at room temperature

Abstract

This paper describes a simple and fast method for the determination of Se, Pb, Cd, Mn, Co, Zn, Cu, Pt, U, Tl, As, Mg, Cr, Be, Ag and Ni in hair by using inductively coupled plasma spectrometry (ICP-MS). Prior to analysis, 50–100 mg of hair samples were accurately weighed into (15 mL) conical tubes. Then, 1 mL of 25% m/v tetramethylammonium hydroxide (TMAH) solution was added to the samples, incubated at room temperature overnigh and then further diluted to 10 mL with 1% v/v HNO₃. After that, samples were directly analyzed by ICP-MS (ELAN DRC II). Rhodium was used as internal standard. Calibration was performed with standards containing 1.0 mg mL⁻¹ of L-cysteine. The method detection limits were 4.0; 0.8; 0.06; 0.8; 0.02; 3.5; 2.3; 0.005; 0.03; 0.02; 0.4; 0.03; 0.09; 0.07; 0.09; 2.0 ng g⁻¹ for Se, Pb, Cd, Mn, Co, Zn, Cu, Pt, U, Tl, As, Mg, Cr, Be, Ag and Ni, respectively. Method accuracy is traceable to Certified Reference Materials (CRMs) 85 and 86 human hair from the International Atomic Energy Agency (IAEA). Additional validation data are provided based on the analysis of hair samples from the trace elements intercomparison program operated by the Institut National de Santé Publique du Quebec, Canada. With the proposed method at least 500 hair samples can be solubilized and analyzed in 3–4 days.