Multi-element analysis of soil and sediment by ICP-MS after a microwave assisted digestion method

This paper describes a method for the multi-element analysis of V, As, Co, Hg, Cd, Mo, Sn, Ba, Be, Cr, Ni, Pb, Cu and Zn in soils and sediments by inductively coupled plasma-mass spectrometry. A microwave digestion procedure was performed in order to obtain complete sample dissolution. Optimum values for instrumental parameters of the ICP-MS were performed and set up. Multi-element acid solutions (without sample matrix matching) can be used for the calibration, thus providing an accurate quantitative analysis. The signal suppression due to HNO3 has been observed for elements showing a high ionisation potential, such as Zn, As and Cd, so the calibration solutions need to be prepared with exactly the same acids (kind and volume) used for the sample mineralisation. The methodology was evaluated by the analysis of four reference materials. Very low values of limit of quantification were obtained, most of them below 100 mu g kg(-1). The accuracy was better than 80% for most of the elements. Good precision values, as relative standard deviation, in the range 0.3-14% were obtained (14% for Mo at the level of 1.28 mg kg(-1)).