Simultaneous determination of ten sweeteners in soybean products using PRiME HLB purification combined with ultra-high-performance liquid chromatography-tandem mass spectrometry

Abstract

A method for determination of ten kinds of sweeteners in soybean products by multi-plug filtration cleanup (m-PFC) combined with ultra-high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was established. The sample was extracted with acetonitrile (containing 1% formic acid), degreased by using n-hexane liquid–liquid extraction and purified by solid phase extraction using an m-PFC column (Oasis PRiME HLB). The analytes were separated by using a Waters ACQUITY UPLC® BEH C₁₈ (2.1 mm × 150 mm, 1.7 μm) column, and gradient eluted with a mixed solution of (5 mmol L⁻¹ ammonium formate +0.1% formic acid) and acetonitrile. The mass spectrometric acquisition was performed by multiple-reaction monitoring (MRM) in both negative and positive ionization mode. Quantitative analysis was performed using an external standard method with matrix-matched calibration curves. Under optimal conditions, a total of ten target compounds were well separated within 10 min, and a good linearity was obtained in the concentration range of 5.00–500 μg L⁻¹ with correlation coefficients greater than 0.99, and the limits of detection (LODs) and quantification (LOQs) for ACE-K, SAC and SCL were 25.0 and 50.0 μg kg⁻¹; the limits of detection (LODs) and quantification (LOQs) for CYC, ASP, ALI, RBA, STV, ADV and NEO were 12.5 and 25.0 μg kg⁻¹,respectively. The recoveries of the ten sweeteners in soymilk samples ranged from 76.9% to 115% at low, medium and high spiked levels (25.0–50.0 μg kg⁻¹, 50.0–100 μg kg⁻¹, and 250–500 μg kg⁻¹), with precisions (RSD) in the range of 0.62–3.98%. This method is simple, rapid, accurate and sensitive, which greatly improves the efficiency of sample analysis and the accuracy of qualitative and quantitative analysis results of the target substances. It could meet the needs of quantitative analysis and qualitative screening of sweeteners in bulk soybean product samples, and provide technical support for rapid analysis of sweeteners in soybean products. It is of great significance for the analysis of trace components of sweeteners in soybean products.