Comparison of conventional and microwave wet acid digestion procedures for the determination of iron, nickel and vanadium in coal by electrothermal atomisation atomic absorption spectrometry
Certified coal standards and Venezuelan coal samples were submitted to conventional and microwave wet acid digestion procedures to assess and compare the efficiency of both decomposition methods. Several acid mixtures and heating power and time settings were investigated in order to achieve the optimum sample treatment conditions. The resulting solutions were analysed by electrothermal atomisation atomic absorption spectrometry to determine their Fe, Ni and V content. The results obtained showed total recovery of the analytes and good accuracy and precision of the measurements. Sample treatment time was reduced from 11–12 h per sample using conventional heating, to 8–10 min per sample using the microwave-heating source.