Determination of 9 Commonly Used Additives in Beverages by Gas Chromatography-Mass Spectrometry with Salting-Assisted Dispersive Liquid-Liquid Microextraction

This study mentioned by the title was conducted to achieve simultaneous detection of commonly used preservatives and antioxidants in beverages. The 5.000 g of beverage sample was taken and mixed with 1.0 mL of 50% (volume fraction) hydrochloric acid solution and 1.0 g of sodium chloride, followed by ultrasonic dissolution. A mixed extractant containing 900 μL of chloroform (extractant) and 900 μL of ethanol (dispersant) was rapidly injected, and the solution obtained was vortexed for 3 min, and centrifuged for 2 min to collect the chloroform phase at the bottom. An additional 900 μL of chloroform was added for repeated extraction, and the two chloroform phases were combined and blown to dryness at 40 ℃ by nitrogen. The residue was reconstituted with 1.0 mL of ethyl acetate, and the solution obtained was passed through a 0.22 μm nylon filter membrane. The filtrate was analyzed by gas chromatography-mass spectrometry. The 6 preservatives (sorbic acid, benzoic acid, methylparaben, ethylparaben, propylparaben, and butylparaben) and 3 antioxidants (butylated hydroxyanisole, butylated hydroxytoluene, and tert-butylhydroquinone) were separated on HP5-MS UI capillary column using temperature programmed condition, ionized by electron impact ion source, detected in selected ion monitoring mode, and qualified by external standard method. It was shown that linear relationships between the mass concentrations of the 9 additives and peak areas of their corresponding quantitative ions were kept in the range of 1.0-100 mg·L^-1, with detection limits (3S/N) in the range of 0.07-0.22 mg·kg^-1. The spike recovery tests at three concentration levels were conducted using blank samples of carbonated beverage, tea beverage, and fruit juice beverage as matrices, giving recoveries in the range of 85.5%-105%, and RSDs (n=6) of the determined values in the range of 1.2%-7.1%. The proposed method was applied to the analysis of 22 actual samples, and benzoic acid in 6 samples and sorbic acid in 5 samples were detected. The detected amounts did not exceed the maximum limits specified in GB 2760—2024 and were consistent with those given by the standard method GB 5009.28—2016.