Determination of p-Hydroxybenzoic Esters (Parabens) in Snus by UPC²-MS/MS

An effective analytical method using QuEChERS coupled with ultra-performance convergence chromatography-tandem mass spectrometry (UPC²-MS/MS) for determination of p-hydroxybenzoic esters (parabens) in snus was developed. In the present work, acetonitrile was selected as extraction solvent, extraction kit (25 mg PSA, 7.5 mg Carbon, 150 mg MgSO₄) was evaluted to purify samples. The target analytes were separated on UPC^{2 TM} HSS C18 SB (3.0 mm×100 mm×1.8 μm) column, and quantified by internal standard method. The optimal separation conditions on UPC² were as follows: the main mobile phase was CO₂, and modifier was methanol-isopropanol (V/V, 1∶1), the flow rate was 1.5 mL/min, the assistant ionization solvent (compensate solvent) was methanol with 0.1% formic acid, the pressure of automated backpressure regulator (ABPR) was 1.03×10⁷ Pa, and the temperature of column was 55 ℃, the single analysis would complete within 3 min. The calibration curves are linear in the range of 0.5-5.0 mg/kg. The average recoveries of three addition levels are in the range of 94.6%-105.6% with RSD less than 5%. The detection results showed that parabens contents in snus are lower than the limits regulated by national standard GB 2760—2014 (<10 mg/kg). The proposed method is environmental friendly, high efficiency, accurate, which is suitable for analysis of parabens in snus.