Precise Determination of Trace Elements in Geological Samples by ICP-MS Using Compromise Conditions and Fine Matrix-Matching Strategy

A simple method for multi-element analysis of geological samples has been developed. In this work, compromise conditions involving optimizing the operating parameters of the ICP, adjustment of ion optics voltages and selection of internal standards were carefully investigated. Matrix trace element-matching procedures were employed, in which the external calibration solutions were prepared by dividing the elements of interest into seven groups of different concentration levels according to their average contents of 20 typical standard reference rock samples. The proposed method offered simple procedure of sample preparation, instrument calibration, improved precision and reasonable element coverage. Detection limits ranged from 0.003–0.1 µg g-1 for heavier mass elements to 0.01–1 µg g-1 for lighter mass elements. Precision was near 1.1–10% RSD (lighter mass elements) and 2.0–8.0% RSD (heavier mass elements), respectively, with the exceptions of tungsten, molybdenum and thorium. Good agreement between certified and found values were achieved for standard reference rock samples AGV-1, BHVO-2 and GSR-3. Analytical data for rare earth elements were in conformity with values from the chondrite normalized curve.