General reliability factors for the quantitation techniques

The following factors are valid for all quantitation techniques, except for Standard addition:

• Quantitation requires that the components of interest are completely resolved from all other components in the chromatogram. Overlapping peaks will produce unreliable results.

• The peak integration parameters (baseline settings) must be correctly selected. The default settings will be satisfactory in many cases, but the integration results have to be checked for all chromatograms.

• All integrations must be performed using the same X-axis base unit. For highest reliability, time is the recommended unit.

• The concentration levels of the standard have to be accurately prepared. Errors in the amount or concentration values will lead to unpredictable results.

• Self-imposed limitations, such as the use of a small number of concentration levels of the standard, also limits precision.

• Precision is improved by the appropriate choice of the concentration range of the standard. The range should extend across the presumed amount in the sample.

• Use of the most appropriate curve model will maximize precision.

• Accuracy is improved if several runs are performed at each level.

• All the runs should be performed consecutively to reduce systematic errors and thereby maximize precision.

Refer to statistical reference books for more detailed information about quantitative analysis. An example is "Statistics for Analytical Chemistry", 3rd Edition 1993, J.C. Miller and J.N. MIller, Ellis Horwood PTR Prentice Hall.