Inductively coupled plasma–mass spectrometry is now such an important technique in archaeology, as elsewhere, that we devote a whole chapter to it. There are now a number of different ICP–MS modes of operation (solution analysis, laser ablation, multicollector, high resolution); this chapter provides a general overview. Further description of the instrumentation for ICP–MS may be found in Harris (1997) and Montaser (1998). Some general applications of solution ICP–MS are discussed by Date and Gray (1989), Platzner (1997), and Kennett et al. (2001).

Types of ICP analysis

Inductively coupled plasma–mass spectrometry (ICP–MS) was first commercialized in 1983, and since then has gradually replaced techniques such as AAS, ICP–OES (Chapter 3), and NAA (Chapter 6) as the method of choice for fast, trace level elemental analysis in a wide range of materials (Fig. 9.1). It offers multielement detection limits below parts per billion (ppb; 10− 9), sometimes down to parts per trillion (ppt; 10− 12), and can give a rapid throughput of samples (commonly 20–50 per day, depending on the number of elements or isotopes required). Most elements can be analyzed, except some of the light elements (H, He, C, N, O, F, Ne, Cl, Ar), and some actinides. Although this encompasses a wide mass range (i.e., 6Li to 238U), the most common mass selector for basic instruments (the quadrupole) has an inherent bias for producing better data at higher masses.