Determination of Platinum Group Elements in Lamprophyre Sample by Nickel Sulfide Fire Assay-Inductively Coupled Plasma Mass Spectrometry

Iron powder was mixed with assaying ingredient and the quantity of FeS was adjusted to 20%~40% in nickel sulfide button. The button was pulverized by water dipping and then dissolved by hydrochloric acid. The solution was filtered and the precipitate was dissolved with aqua regia. Platinum group elements (PGEs) in the solution were determined by inductively coupled plasma mass spectrometry (ICP-MS) with Cs as internal standard. The modified method reduced the total procedure blank value and improved the detection limits of PGEs remarkably. The method has been verified by determination of PGEs in National Standard Reference Materials（GBW 07288， GBW 07290） and has been applied to the determination of PGEs in lamprophyres of Ailaoshan gold delt, Yunnan province with satisfactory results. The detection limits of the method for PGEs are 0.001~0.01 ng/g with the precision of 7.49％～16.6％RSD (n=5). 