Optimization of QuEChERS extraction of steroid hormones from infant formulae for mass spectrometric analysis

Abstract

A rapid, simple and accurate extraction QuEChERS method was used for simultaneous determination of 22 hormones with a wide range of polarities in 35 infant formulae by use of LC–ESI-MS/MS. In the present method, some changes were made compared to other methods, which include eliminating the enzymatic hydrolysis step, derivatization and performing analysis a wide range of analytes with different polarities in single run. Three validation runs based on three levels of pre-extraction spiked quality control samples were conducted. Limits of detection obtained by use of the QuEChERS methods were less than those of other extraction methods with the same matrix and recoveries were more satisfactory. Under optimal experimental conditions, good linearity was observed in the range of 1–50 µg L−1. Limits of detection and quantification were in the range of 0.33–1.66 µg L−1 and 1–5 µg L−1, respectively and recoveries of analytes ranged from 73 to 118%. The amount of hormone residues in the samples was not significant. The present method is proposed for routine analysis of hormones potentially present in infant formula and other milk-derived products.