Inductively coupled plasma optical emission advantages

Multielement analysis will become more important in industrial hygiene analysis as the number of elements per sample and the numbers of samples increases. Additional requirements that will push development of atomic absorption techniques and may encourage the use of new techniques are lower detction and sample speciation. Sample speciation will probably require the use of a chromatographic technique coupled to the spectroscopic instrumentation as an elemental detector. This type of instrumental marriage will not be seen in routine analysis. The use of Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES) (17), Zeeman-effect atomic absorption spectroscopy (ZAA) (18), and X-ray fluorescence (XRF) (19) will increase in industrial hygiene laboratories because they each offer advantages or detection that AAS does not. 

In both total and sequential dissolutions, the result is a solution containing the components of rocks and soils. This solution is then analyzed by different methods. Mostly, spectroscopic methods are used atomic absorption and emission spectroscopic methods, ultraviolet, atom fluorescence, and x-ray fluorescence spectrometry. Multielement methods (e.g., inductively coupled plasma optical emission spectroscopy) obviously have some advantages. Moreover, elec-troanalytical methods, ion-selective electrodes, and neutron activation analysis can also be applied. Spectroscopic methods can also be combined with mass spectrometry. 

This chapter discusses the advantages and limitations of the multielement analysis of biologically related samples using induction-coupled plasma optical emission. The sample categories covered include grains, feeds, fish, bovine liver, orchard leaves, and human kidney stones. These materials have been simultaneously analyzed for copper, nickel, vanadium, chromium, phosphorus, cobalt, lead, potassium, zinc, manganese, iron, strontium, sodium, aluminum, calcium, magnesium, silicon, boron, and beryllium, often with limited amounts of sample. 

As in inductively coupled plasma optical emission (ICP-OES) spectra, in addition to atomic lines, intense ionic lines are also observed, the use of an ICP as an ion source for MS seemed logical, but overcoming the difference in pressure between the ICP (generated at atmospheric pressure) and the mass spectrometer (10 —10 mbar) proved difficult and had to be accomplished via the use of a two-cone interface. Despite the advantages that double-focusing sector field mass spectrometers (higher mass resolution) and TOP analyzers (high data acquisition speed) can offer, approximately 90% of the ICP-MS units used worldwide are equipped with a quadrupole filter for mass analysis. 

---