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.

Background: Rosemary extracts are derived from the leaves of Rosmarinus officinalis and commonly employed as natural food preservative. They serve as natural antioxidants in food, preventing spoilage and extending shelf life.

Objective: This study aimed to develop a modified QuEChERS extraction with liquid chromatography tandem mass spectrometry for the analysis of rosemary extracts in food as sum of its markers Carnosol and Carnosic Acid.

Method: Carnosol and Carnosic Acid in food were extracted by a modified QuEChERS extraction after the addition of analyte protectant during extraction and analyzed by liquid chromatography tandem mass spectrometer via internal standard calibration method. 2,2'-Isopropylidienediphenol and Podocarpic acid were used as internal standards for Carnosol and Carnosic Acid, respectively.

Results: The Limit of Detection of Carnosol and Carnosic Acid were all less than 1 mg/kg, while their corresponding values of Limit of Quantitation ranged from 1.44-3.12 mg/kg in various matrices. Spike recoveries at three fortification levels (10, 50 and 300 mg/kg) were all within 90-110% with %RSD less than 10% in all cases.

Conclusions: A modified QuEChERS extraction with LC-MS/MS detection for the analysis of Rosemary extracts in food was successfully developed, validated and demonstrated to be fast, robust and reliable.

Highlights: The developed modified QuEChERS extraction with LC-MS/MS detection offered a fast and efficiency way to analyse rosemary extracts in various food during routine food surveillance programme.