Analytical quality control (AQC) refers to all those processes and procedures designed to ensure that the results of laboratory analysis are consistent, comparable, accurate and within specified limits of precision.
[1] Constituents submitted to the analytical laboratory must be accurately described to avoid faulty interpretations, approximations, or incorrect results.
AQC processes are of particular importance in laboratories analysing environmental samples where the concentration of chemical species present may be extremely low and close to the detection limit of the analytical method.
Initial control of the complete system can be achieved through specification of laboratory services, instrumentation, glassware, reagents, solvents, and gases.
The quality of individual AQC efforts can be variable depending on the training, professional pride, and importance of a particular project to a particular analyst.
In cases such as changes in synthesis of the drug substance, changes in composition of the finished product, and changes in the analytical procedure, revalidation is necessary to ensure quality control.