Development of a Modified QuEChERS Extraction for the Detection of Rosemary Extracts (E392) Expressed as Sum of Carnosol and Carnosic Acid in Food by LC-MS/MS.

This article focuses on the development and validation of a modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) extraction method combined with liquid chromatography tandem mass spectrometry (LC-MS/MS) for detecting rosemary extracts (E392) in food. Rosemary extracts, derived from Rosmarinus officinalis, contain the major antioxidant markers carnosol (CAO) and carnosic acid (CAA), which are regulated as food preservatives with maximum permitted levels (MPLs) ranging from 15 to 700 mg/kg depending on jurisdiction and food type. The proposed method uses analyte protectants to prevent degradation during extraction and employs internal standards 2,2'-isopropylidienediphenol (IPOL) and podocarpic acid (POA) for quantification. Validation results demonstrated limits of detection below 1 mg/kg, limits of quantitation between 1.44 and 3.12 mg/kg, recoveries within 90–110%, and precision with relative standard deviations under 10% across diverse food matrices, meeting regulatory requirements. This approach offers a fast, robust, and reliable analytical tool suitable for routine food surveillance of rosemary extract additives.