Correction of the Matrix Effect in the Determination of Benzoylphenylurea Insecticides in Vegetables

Abstract

The matrix effect in the analysis of benzoylphenylurea insecticides, in four vegetables by HPLC using continuous on‐line post‐elution photoirradiation with fluorescence detection, was investigated by applying the analysis of covariance (ANCOVA). Experimental results show that a matrix effect exists in the quantification of diflubenzuron and flufenoxuron in cucumber and flufenoxuron in green bean. In order to correct this effect, two different methods have been compared in the analysis of real samples: the first one was based on the use of calibration solutions prepared in blank matrix extracts for the quantification of the target analytes in the different matrices, and the second one consisted of the establishment of a correction function. The obtained results showed that the application of the correction function leads to results very similar to those obtained when the quantification was carried out using calibration curves prepared in blank matrix extract; the utility of this function is demonstrated to eliminate the matrix effect in the quantification of benzoylphenylurea insecticides in real samples with the advantages that this presents.

Keywords:

• Benzoylphenylurea insecticides
• Photochemically induced fluorescence
• HPLC
• ANCOVA
• Matrix effect
• Vegetables

Acknowledgments

The authors are grateful to DGCIYT (Project BQU 2000‐1166) for financial support.