Direct solid sampling electrothermal atomic absorption spectrometric determination of toxic and potentially toxic elements in certified reference materials of brown coal fly ash

This work describes a method for the direct determination of Bi, Cd, Cr, Ni, Pb, Sb, Sn and Zn in reference materials of brown coal fly ash, using solid sampling electrothermal atomic absorption spectrometry. The use of chemical modifiers was found to be necessary for obtaining reproducible and sufficiently sensitive signals for the analytes under study. The mixture of Pd and Mg(NO3)2 was used for the determination of Bi, Cd, Pb, Sb, Sn and Zn, W (permanent modifier) in combination with Mg(NO3)2 (as aqueous modifier) provided well-defined signal profiles for Cr and Ni determination in coal fly ash samples. A systematic study focused on the use of alternative (less sensitive) lines for obtaining sufficient sensitivity. The following analytical lines were used: Bi 306.8 nm, Cd 326.1 nm, Cr 520.6 nm, Ni 305.1 nm, Pb 205.3 nm, Sb 206.8 nm, Sn 300.9 nm, Zn 307.6 nm. The limits of detection were 0.057 μg g−1 for Bi, 0.21 μg g−1 for Cd, 1.1 μg g−1 for Cr, 1.4 μg g−1 for Ni, 4.0 μg g−1 for Pb, 0.13 μg g−1 for Sb, 0.33 μg g−1 for Sn and 16 μg g−1 for Zn, respectively. - Highlights: ► DSS-ETAAS might be an attractive alternative to the conventional ETAAS. ► Direct analysis of solids could be used in order to improve the sampling capacity. ► The CRMs of coal fly ashes were used for development of the DSS-ETAAS method. ► Selection of suitable modifiers to achieve the unification of atomization kinetics. ► DSS-ETAAS used for direct determination of potentially toxic and toxic elements.