ABSTRACT
The analyst today has a wide range of analytical instrumentation from which to choose; the factors that affect the choice are described by McLaughlin et al. (1979) and van Loon (1985). Hislop (1980) has developed analytical criteria for selection of an analysis technique based on accuracy, precision, limit of detection, elemental coverage, single or multielement, and determined chemical form. More recently, Sturgeon (2000) states that sample analysis is characterized by the interplay of at least three domains of activity: sample preparation, sample introduction, and instrumentation. Additional constituents exerting an effect are calibration, data reduction and analysis, and effective quality assurance/quality control parameters. The more practical considerations of instrument availability, cost, and sample form and quantity may become the governing factors rather than basing the choice on the criteria given by Hislop (1980). Analysts themselves, their skill and experience, can also be factors when selecting a particular instrument when more than one is available. The issues of accuracy and precision are significant considerations. Accuracy is the ability to obtain the “true” value and is dependent to a large degree on the availability and use of reliable standards. Precision, on the other hand, is a measure of the degree of variability of an obtained result determined by repeated analyses of the same sample through all the steps from sample preparation to the final obtained result. Horwitz (1982) also has evaluated various analytical procedures by assigning levels of performance based on his years of use in the determination of various elements and substances in various materials. Further consideration of these important factors is beyond the scope of this laboratory guide; the above
references are provided to alert the reader to the factors that should be considered when selecting an analytical procedure.
