School of Engineering and Science - Jacobs University

1. Introduction
The advent of inductively coupled plasma mass spectrometry (ICPMS) has
proven enormously beneficial to geochemical studies. Since commercialization of
ICPMS technology in the early 1980’s, ICPMS has become the method of choice for
geochemical analyses, and is ideal for trace metal determinations and isotopic studies
of many elements. The widespread implementation of ICPMS technology results from
its ability to quickly quantify a large number of elements (>40) in geological samples
on a routine basis. Additionally, ICPMS offers instrument sensitivity that permits
quantification of ng/kg (parts-per-trillion, ppt) concentrations of many elements
regardless of sample matrix, and as such is ideally suited for studies of geochemically
diverse samples. This report describes the ICPMS analytical methods employed
within the Geochemistry Lab at Jacobs University Bremen (JUB) and includes a
critical discussion of the precision and accuracy of these methods.
The Geochemistry Lab at JUB is relatively new, with construction of the lab
completed in the Summer of 2004. In the Fall of 2004 a PerkinElmer DRC-e
quadrupole inductively coupled plasma mass spectrometer (ICPMS) was installed,
which is the principal analytical instrument for determinations of trace metal
concentrations. This report is not intended to provide detailed information regarding
basic ICPMS principles and technology, and the reader is referred to Thomas (2003)
for a thorough review. When samples are decomposed into liquid form, ICP
instruments are ideal for multi-element geochemical analyses, as they allow relatively
fast sample introduction into mass spectrometers, and are readily automated for the
processing of large numbers of samples.
This report describes the steps utilized at JUB to obtain accurate trace metal
concentration data in a variety of rock types, and proceeds from the processing of
hand samples to the decomposition of sample powders, and finally to the methods
employed to ensure the accuracy of the reported data. Sample preparation techniques
are not the primary focus of this paper, and are only briefly discussed. Rather,
considering the relatively short existence of the Geochemistry Lab at JUB and the
necessary development of accurate and routine geochemical analytical techniques,
most of the discussion will focus on a critical assessment of the methods employed in
ICPMS trace metal determinations in a variety of geologic materials, and the relative
precision and accuracy of these measurements.
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