Simultaneous Determination of Sweeteners and Pigments in Essences and Spices by UHPLC-MS/MS

UHPLC-MS/MS was applied to the determination of 3 sweeteners and 5 pigments in samples of essence or spice. The sample was extracted with a mixture of methanol and ammonia. The extract was separated on Waters BEH C18 column, with a mixture of methanol and 10 mmol·L-1 ammonium acetate solution (containing 1 mL of glacial acetic acid per liter of solution) in various ratios as mobile phase in gradient elution. ESI+ (for pigment sample), ESI- (for sweetener sample) and MRM were adopted in MS. Linear relationships were found between values of peak areas and mass concentrations of the 8 analytes in definite ranges, with detection limits (3S/N) in the range of 0.09-1.2 mg·kg-1. Results of test for recovery found by standard addition method were in the range of 82.9%-118%, and RSD′s (n=5) were less than 6%.