| Fluorescent whitening agents are important additive in all kinds of products of modern industrial production. However, fluorescent whitening agents are excessive used in some relating to human health products, which has caused serious social problems.In recent years, the phenomenon of abusing fluorescent whitening agent is becoming more and more serious, which have aroused widespread concern in society.Considering the consumer’s safety and health, it is of immediate necessity to develop efficient methods for qualitative and quantitative detection of fluorescent whitening agent.Four kinds of fluorescent whitening agents(CBS, VBL, CXT, BBU) that commonly used in modern industrial production have been researched in this dissertation. The traditionalmethods of molecular resonance light scattering spectrometry, fluorescence spectroscopy, synchronous fluorescence spectroscopy, fluorescence on the paper digital colorimetric and three-dimensional fluorescence spectrometry have been used to establish new detection methods. These new methods have been used to qualitative and quantitative detection of the fluorescent whitening in laundry detergent,napkins,and edible fungus and have obtained good results. The specific research contents as follows:1. The new method for determination of fluorescent whitening agent(VBL) by resonance light scattering spectrometry has been established,which has been used to analyze the napkin. The maximum intensity of resonance light scattering can be detected when λex=λem=469 nm. In addition, there is a good linear relationship between resonance light scattering intensity and the concentration of VBL. The quantitative standard curve is Y = 9.70 x + 17.70, the correlation coefficient is R = 0.9978, the linear range is 0.01-4.0 μg/m L, and the detection limit is 0.03 ug/m L. This method can meet the requirements of detection. We have discussed the purity of experimental water, the effect of p H to the stability of VBL solution, and the condition optimization of sample pretreatment. Satisfactory results have been obtained by new analytical method.2. The new method for quantitative determination of fluorescent whitening agent(CXT) via resonance light scattering spectrometry has been established,which has been used to analyze the edible fungus.Meanwhile, surfactant(CTAB) sensitization CXT has also been explored. The new method shows that there is a relatively stable resonance light scattering peak when λex=λem=405 nm. In addition, there is a linear relationship between its strength and the concentration of CXT. The quantitative standard curve is y=13.45x-1.58, the correlation coefficient is R=0.9985, the linear range is 0.5-15.0 μg /m L, and the detection limit is 0.09 μg/m L. We have discussed p H of the solution, the condition optimization of sample pretreatment, and the surfactant(CTAB) sensitization CXT. Furthermore, stable association was formed between CTAB and CXT, which enhanced the strength of fluorescence and increased the sensitivity of sample determination.This analysis result is satisfactory.3. The new method for quantitative determination of fluorescent whitening agent(CBS) in the laundry detergent via paper fluorescence digital colorimetric has been established. The sample is pointed on the quantitative filter paper by micro injector. We have analyzed the fluorescence images which were taken in dark conditions under the UV lamp. There is a linear relationship within a certain range of the integral value of image sample point gray area and the concentration of CBS. There is a good linear relationship when 2 μL of sample is used and concentration was1.0-40.0 μg/m L.The quantitative standard curve is y= 2031.7x+ 7196.5, correlation coefficient R = 0. 9952. This method has been used to analyze the actual samples, andthe result was the same as fluorescence spectrophotometric method.4. Multiple kinds of molecular fluorescence spectrum have been used to qualitative determinationof four kinds of fluorescent whitening agent.The traditional resonance light scattering spectrometry, fluorescence spectroscopy, synchronous fluorescence spectroscopy and three-dimensional fluorescence spectrometry are used to scantheaqueous solution and anhydrous ethanol solution of fluorescent whitening agent CBS, VBL, CXT, BBU respectively. Several kinds of fluorescence spectrum have obtained and different fluorescent whitening agent has good distinction.The position of the peak inflection points are not consistent in the fluorescence spectra of fluorescent whitening agent that obtained by excitation spectra and emission spectra and the three dimensional fluorescence spectra, which can be used to distinguish all kinds of fluorescent whitening agent.The research results show that the detection methods of analysis fluorescent whitening agent are featured with high speed, high detection sensitivity, and low cost. This new methods have established in this dissertation can provide the characteristic information of the fluorescent whitening agent, and realize rapid identification of trace amounts of fluorescent whitening in various types of products. |
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