Simultaneous Determination of Seven Fluorescent Whitening Agents in Food Contact Paper Package Materials by High Performance Liquid Chromatography Tandem Triple TOF-High Resolution Mass Spectrometry

A method for screening and quantitative detection of seven fluorescent whitening agents (FWAs, FWA368, FWA367, FWA185, FWA 184, FWA52, FWA135 and FWA393) in food contact paper package materials was established by high performance liquid chromatography tandem triple TOF high resolution mass spectrometry (LC-Triple TOF MS). The paper samples were extracted with chloroform under ultrasonication, concentrated, separated in a C18 column (100 mm x 2.1 mm i. d., 2.6 mu m) by gradient elution using methanol and 0.1% formic acid in water as mobile phase, and detected in positive ESI and TOF-MS IDA MS/MS mode. The qualitative analysis of seven FWAs was confirmed by synergistic effect of retention time, mass accuracy of precursor, isotope distribution of the precursor, and library search. The analytes were quantified by peak areas of the TOF. MS extracted ions. The results indicated that, all of the seven FWAs presented favorable mass accuracy less than 3 x 10(-6), good linearity in the concentration of 4-400 mu g/L with the correlation coefficients larger than 0.996, low instrument detection limits (S/N = 3) of 1.0-5.0 mu g/kg, appropriate recoveries ranged from 81.2% to 98.9% at three spiked levels, and satisfactory RSD (n = 6) of 5.2% - 9.1%. 13 samples were tested using the method and one sample was found FWA 184 with concentration of 287 mu g/kg. The method is efficient and accurate, and is suitable for analysis of the seven FWAs in food contact paper package materials.