Simultaneous determination of V, As, Se, Cd, Ba and Pb in coal by ICP-MS after high pressure oxygen combustion

A simple decomposition procedure by a high pressure oxygen combustion method was employed for the determination of six elements (V, As, Se, Cd, Ba and Pb) in coal by inductively coupled plasma mass spectrometry (ICP-MS). Combustion under 3 MPa pressure of oxygen in a sealed bomb is a simple and effective method for the decomposition of carbonaceous materials. Organic components are burnt to form CO2 and H2O. Other components also form oxides, which are absorbed in the absorbing solution of a 5 mL of 5% HNO3 - 1% H2O1 Mixed solution put in a bomb. To completely decompose the sample, 600 mg of starch is added to 300 mg of a ground coal sample. Though ignition normally takes about 1/2 s, 30 min is required before opening the bomb to keep to the oxides absorbed into the absorbing solution. The accuracy of the procedure was evaluated by comparing the determination value of each element with a certified value of a standard reference material. In this study, NIST SRM 1632c and 1632b, given by the National Institute for Standards and Technology in Washington DC, USA were used as standard reference materials. The results obtained by ICP-MS after high pressure oxygen combustion showed good agreements with the certified values of NIST 1632c for 6 elements (V, As, Se, Cd, Ba, Pb). This method was applied to the determination of 6 elements in coal real samples supplied by CCUJ (Center of Coal Utilization Japan).