Determination of As, Cd, Ni and Pb in human hair by electrothermal atomic absorption spectrometry after sample treatment with tetramethylammonium hydroxide
As. Ribeiro et al., Determination of As, Cd, Ni and Pb in human hair by electrothermal atomic absorption spectrometry after sample treatment with tetramethylammonium hydroxide, MICROCHEM J, 64(1), 2000, pp. 105-110
A very simple alternative dissolution procedure for a human hair sample wit
h tetramethylammonium hydroxide was proposed. The sample was mixed with a s
mall amount of the reagent and the dissolution occurred in approximately 2
h at room temperature or in approximately 10 min under heating at 60-70 deg
rees C. After dissolution, the analytes, As, Cd, Ni and Pb were determined
in a certified reference human hair by electrothermal atomic absorption spe
ctrometry, using calibration curves obtained by separately pipetting the an
alyte, the modifier and the reagent solutions into the graphite tube. A mix
ture of Pd and phosphate for Pb and Pd alone for As and Cd were used as mod
ifiers, while no modifier was employed for Ni. The temperature program was
optimized through pyrolysis and atomization curves. The limits of detection
in the sample were 0.4, 0.009, 0.1 and 0.5 ppm, respectively, for As, Cd,
Ni and Pb. The relative standard deviations were lower than 5%. The obtaine
d concentrations agreed with the certified values and also with the found c
oncentrations by using a conventional acid dissolution. (C) 2000 Elsevier S
cience B.V. All rights reserved.