Using additional standards for increasing the accuracy of quantitative chromatographic analysis

Abstract

Uncontrolled partial losses at the step of sample injection into a gas chromatographic column increase errors of determination by the external standard, absolute calibration, and standard addition methods. Modified method is proposed for quantitative analysis; it includes the introduction of additional standards into test samples and calculations by the ratio between the areas of chromatographic peaks and peaks of standards rather than the absolute areas of chromatographic peaks. The calculation equations are presented for modified methods of quantitative analysis using additional standards, including those for estimating random errors of determination. The relative standard deviations of peak areas were shown to be 6–38-fold lower than the analogous statistical characteristics of absolute areas. This ensures a high accuracy of quantitative determinations even under the conditions of low reproducibility of sample dosing. Solvents contained in the analyzed samples can be used as additional standards. This version can be recommended as a routine method of data representation and processing.