The science of chemical analysis and the technique of mass spectrometry

The subject of chemical analysis is traditionally organized by the techniques employed. This method of classification fragments the subject and provides little basis for learning how to approach the development of new methods. A concept underlying all chemical analyses is the selection and implementation of the quality of the analyte that distinguishes it from the rest of the sample components, The analytical process is the selection of the differentiating characteristic (DC), the development of a probe to test the sample for the DC, the anticipation and measurement of the response of the sample to the probe, the interpretation of the data, and the evaluation and improvement of the method. The range of options available at each step illustrates the latitude for creativity exercised by former analysts and available for methods yet to be developed. In mass spectrometry, the differentiating characteristics are seen to be ionizability, mass-to-charge ratio, and fragmentation pattern. The selectivity of the combination of differentiating characteristics employed greatly affects the detection limit in trace analysis. ne methods of probing, measurement, and data analysis are related to the analytical goals (quantitation, detection, or identification). Measurements are based on conversion devices and counting techniques. When counting statistics are considered, the impact of peak overlap in chromatography/mass spectrometry is seen to be a loss of dynamic range in the concentration of the analytes. (C) 2001 Elsevier Science B.V.