ABSTRACT
Analytical chemistry includes both qualitative and quantitative analysis. Qualitative analysis is concerned with what is present and quantitative analysis is concerned with how much. Methods of quantitative analysis are based on chemical reactions, on the measurement of certain chemical and physical properties, or on the measurement of a combination of chemical and physical properties. Quantitative analytical techniques may be divided into two main groups: wet chemistry and instrumentation analytical techniques. Calibrations are performed at the beginning of the analysis to make sure that the instrument is working properly. The number and the optimum concentration range of the calibration standards used for each particular method is given by the approved methodology and described by the laboratory standard operation procedures. The performance check is an indicator of any deterioration of either the lamps or the spectrophotometer and shows the optimal condition of the instrument.
