Simultaneous Determination of 15 Fluorescent Whitening Agents in Food Contact Paper Products by High Performance Liquid Chromatography Coupled with Fluorescence Detection

KeyWord:fluorescent whitening agents  food contact paper products  high performance liquid chromatography  fluorescence detection

Abstract:

      A high performance liquid chromatography(HPLC) with fluorescence detection based on a simple pretreatment method was established for the simultaneous determination of 15 kinds of fluorescent whitening agents in food contact paper products,with widely used and low-cost ionic fluorescent whitening agents as well as some fluorescent whitening agents such as fluorescent whitening agent 393 and fluorescent whitening agent 184 concerned in the European Union and China as the research objects.The analysis objects included ionic and non-ionic fluorescent whitening agents,some of which were isomers,including ionic fluorescent whitening agents 220 and 24,and non-ionic fluorescent whitening agents 199A and 199B.At present,the chromatographic analysis methods for fluorescent whitening agents are mainly corresponding to ionic and non-ionic fluorescent whitening agents,and the chromatographic separations are mainly carried out with C18 column.However,there are few studies on simultaneous determination of the two types of fluorescent whitening agents and some of their isomers.In that case,a series of parameters such as chromatographic column,mobile phase,flow rate,pH value and elution gradient were optimized in this paper to achieve the chromatographic separation and simultaneous detection of 15 fluorescent whitening agents.Consequently,the samples were separated using an Agilent Pursuit 5 PFP(4.6 mm¡Á250 mm¡Á5.0 ¦Ìm) by gradient elution,with acetonitrile,methanol and the solution of tetrabutyl ammonium bromide as the mobile phases.In the pretreatment process,the extraction solvent,extraction time,extraction volume and separation method were optimized to realize the effective extraction of fluorescent whitening agents from food contact paper products.Specifically,during the analysis process,the samples were crushed,and the one-step solvent extraction was applied to extract the fluorescent whitening agents in samples with alkaline extract solution through ultrasonic process.Subsequently,the extract solution was filtrated,and analyzed by high performance liquid chromatography.Results showed that there were good linear relationships for the calibration curves of 15 fluorescent whitening agents,with their correlation coefficients(r) not less than 0.998 9.The limits of detection and the limits of quantitation were in the ranges of 0.030-0.60 mg/kg and 0.10-2.0 mg/kg,respectively.Under the detection limited concentrations set in this paper,15 kinds of fluorescent whitening agents were found to exhibit no obvious fluorescence phenomenon by ultraviolet light illumination method,which indicated that the method reached a high sensitivity.The recoveries for 15 fluorescent whitening agents at three spiked levels ranged from 90.0% to 108%,with relative standard deviations of 0.70%-7.1%.The established method was successfully used for the determination of 13 commercial paper products with good practicability,simplicity and sensitivity.The establishment of this method could realize the further identification of the types and contents of fluorescent whitening agents in food contact paper with positive fluorescence phenomenon,which has a certain guiding significance for the quality and safety management and control of food contact paper products.