Development and validation of a screening and quantification method for simultaneous determination of seven fluorescent whitening agents in commercial flour using UPLC-MS/MS

A sensitive UPLC-MS/MS method was established for the simultaneous determination of seven fluorescent whitening agents in flour matrix. Samples were ultrasonically extracted by trichloromethane-acetone. Then analytes were separated on a C18 column and detected by MS/MS. The developed method was validated in terms of the linearity, matrix effect, accuracy and precision. The method showed a good linearity (r > 0.997) for all analytes in their respective concentration ranges. The LOQ for seven analytes were in the range of 2.5-25.0 mu g/kg. The matrix effect was not significant and almost negligible. The average recoveries of seven analytes from the negative samples spiked at three different concentrations were in a range from 81.5% to 105%. The intra-day precision and inter-day precision were in the ranges of 2.9-9.0% and 6.7-11.2%. The developed method was successfully applied to analyze forty commercial flours and FWA184 was detected in three samples with the concentrations of 31-60 mu g/kg.