An expression of reflectance of fluorescent dyes in emission region was used in this article. Through the analysis of the spectral radiance factor of fluorescent whitening agents(FWA), the color matching of FWA was st...An expression of reflectance of fluorescent dyes in emission region was used in this article. Through the analysis of the spectral radiance factor of fluorescent whitening agents(FWA), the color matching of FWA was studied and the three-region method of color matching method was put forward. The method was proved to be reliable for the dyes used and was easy to apply for the color matching of FWAs.展开更多
The inclusion complexation behavior of 2,5-Bis(5-tert-butyl-benzoxazol-2yl)-thiophene (UVOB) with native β-cyclodextrin (βCD) and βCD-monochlorotriazinyl (βCD-MCT) was evaluated by fluorescence spectroscopy. The a...The inclusion complexation behavior of 2,5-Bis(5-tert-butyl-benzoxazol-2yl)-thiophene (UVOB) with native β-cyclodextrin (βCD) and βCD-monochlorotriazinyl (βCD-MCT) was evaluated by fluorescence spectroscopy. The association constant (K<sub>s</sub>), stoichiometry, , and were evaluated at 25℃ ± 0.1℃ in phosphate buffer solution (pH = 10.5, 0.1 mo•dm<sup>–3</sup>) in order to find out the complex formation ability and stability. Fluorescence enhancement for UVOB and UVBNB with both CDs has been observed as a result of the complex formation. A stoichiometry 1:1 for UVOB in both CDs was observed;a stoichiometry 3:1 for UVBNB in both CDs has been observed. The K<sub>s</sub>values for UVOB were 4916 ± 137 M<sup>–1</sup> and 655 ± 19 M<sup>–1</sup> (acetone: water 90/10, v/v) with βCD and βCD-MCT, respectively. The value obtained indicates a spontaneous and stable complex formation, but the complex βCD-UVOB showed high K<sub>s </sub>value as an indicative of a high concentration of complex formed. Additionally, K<sub>s </sub>and thermodynamic parameters and were evaluated in a commercial product UVBNB (UVOB, 13%, v/v). In aqueous solution, the values obtained were 2552 ± 115 and 1787 ± 75 M<sup>–1</sup> respectively. Complexation of UVOB with CDs is an interesting approach for utilization of UVOB in aqueous systems without the need of solvents and or surfactants used in commercial product (UVBNB).展开更多
Adsorption kinetics for a stilbene derivative type fluorescent whitening agent (FWA) on fiber surfaces was studied based on a real-time spectroscopic measurement system. Results showed that the time-dependent behavior...Adsorption kinetics for a stilbene derivative type fluorescent whitening agent (FWA) on fiber surfaces was studied based on a real-time spectroscopic measurement system. Results showed that the time-dependent behavior of FWA agrees to that of a mono-molecular adsorption layer on fiber surfaces,as characterized in Langmuir-type expression. The adsorption has two distinguishable stages includ-ing initial fast phase with the primary constant of 1.51×1014 and the later near-equilibrium phase with the secondary constant of 4.96×10-4. The maximum amount of FWA adsorbed on fiber surfaces is 1.67×10-4g (per dry weight based fiber) in the initial phase. A mathematical model of adsorption kinetics was therefore established and evaluated. This model is important for the optimization of FWA applica-tion in papermaking.展开更多
Facial mask is a kind of skin care cosmetics, in which fluorescent whitening agents（FWAs） were added to make face skin look whiter and brighter. In this work, pig skin was used instead of human skin to test the meth...Facial mask is a kind of skin care cosmetics, in which fluorescent whitening agents（FWAs） were added to make face skin look whiter and brighter. In this work, pig skin was used instead of human skin to test the methods. Three methods, including pig skin migration fluorescent spectrophotometry（FS）, fiber paper migration FS, and fiber paper migration visual colourimetry（VC）, were developed for determining the migration amount of FWAs from facial mask to pig skin. In the methods, a self-assembly light source and fluorescence collecting unit was used. The unit can be easily moved and the measurement was very convenient. Some experimental conditions were optimized. The fiber paper migration VC can give semi-quantitative results and was the simplest one in the three methods because collec- tion, separation and detection of the fluorescence were not needed. Both the pig skin migration FS and fiber paper migration FS can give quantitative results and compared with fiber paper migration FS, the pig skin migration FS could give more practical results by simulating the real way of using facial mask. The limits of detection for disodium 4,4＇-bis[（4-anilino-6-hydroxyethylamion-1,3,5-triazin-2-yl）amion]stilbene-2,2＇-disulphonate（VBL） obtained by pig skin migration FS and fiber paper migration FS were 0.03 and 0.05 mg/m2, respectively. 96 kinds of samples were analyzed and the migration amounts of FWAs in 21 kinds of samples were detectable. Correlations between migration amounts obtained by the three methods were very good. Experimental results indicate that the present methods can be applied to the determination of migration amount of FWAs in facial masks.展开更多
In this paper,a systematic study about the fluorescence spectrum characteristics of fluorescent whitening agent VBL in solution with the different effects,including the pH and solvent,was conducted.The fluorescence qu...In this paper,a systematic study about the fluorescence spectrum characteristics of fluorescent whitening agent VBL in solution with the different effects,including the pH and solvent,was conducted.The fluorescence quantum yields in 25 different solvents were measured by the reference of quinine sulfate.According to these a new fluorescence determinations of the VBL in paper was built.The linear regression equation of the method is IF = 0.82 + 6.18 ×107c(mol/L) with a correlation coefficient(r) of 0.9992.The linear range of the method is from 0 to 2.85×10-6g/mL and the detection limit is 9.59×10-9g/mL.展开更多
文摘An expression of reflectance of fluorescent dyes in emission region was used in this article. Through the analysis of the spectral radiance factor of fluorescent whitening agents(FWA), the color matching of FWA was studied and the three-region method of color matching method was put forward. The method was proved to be reliable for the dyes used and was easy to apply for the color matching of FWAs.
文摘The inclusion complexation behavior of 2,5-Bis(5-tert-butyl-benzoxazol-2yl)-thiophene (UVOB) with native β-cyclodextrin (βCD) and βCD-monochlorotriazinyl (βCD-MCT) was evaluated by fluorescence spectroscopy. The association constant (K<sub>s</sub>), stoichiometry, , and were evaluated at 25℃ ± 0.1℃ in phosphate buffer solution (pH = 10.5, 0.1 mo•dm<sup>–3</sup>) in order to find out the complex formation ability and stability. Fluorescence enhancement for UVOB and UVBNB with both CDs has been observed as a result of the complex formation. A stoichiometry 1:1 for UVOB in both CDs was observed;a stoichiometry 3:1 for UVBNB in both CDs has been observed. The K<sub>s</sub>values for UVOB were 4916 ± 137 M<sup>–1</sup> and 655 ± 19 M<sup>–1</sup> (acetone: water 90/10, v/v) with βCD and βCD-MCT, respectively. The value obtained indicates a spontaneous and stable complex formation, but the complex βCD-UVOB showed high K<sub>s </sub>value as an indicative of a high concentration of complex formed. Additionally, K<sub>s </sub>and thermodynamic parameters and were evaluated in a commercial product UVBNB (UVOB, 13%, v/v). In aqueous solution, the values obtained were 2552 ± 115 and 1787 ± 75 M<sup>–1</sup> respectively. Complexation of UVOB with CDs is an interesting approach for utilization of UVOB in aqueous systems without the need of solvents and or surfactants used in commercial product (UVBNB).
文摘Adsorption kinetics for a stilbene derivative type fluorescent whitening agent (FWA) on fiber surfaces was studied based on a real-time spectroscopic measurement system. Results showed that the time-dependent behavior of FWA agrees to that of a mono-molecular adsorption layer on fiber surfaces,as characterized in Langmuir-type expression. The adsorption has two distinguishable stages includ-ing initial fast phase with the primary constant of 1.51×1014 and the later near-equilibrium phase with the secondary constant of 4.96×10-4. The maximum amount of FWA adsorbed on fiber surfaces is 1.67×10-4g (per dry weight based fiber) in the initial phase. A mathematical model of adsorption kinetics was therefore established and evaluated. This model is important for the optimization of FWA applica-tion in papermaking.
文摘Facial mask is a kind of skin care cosmetics, in which fluorescent whitening agents（FWAs） were added to make face skin look whiter and brighter. In this work, pig skin was used instead of human skin to test the methods. Three methods, including pig skin migration fluorescent spectrophotometry（FS）, fiber paper migration FS, and fiber paper migration visual colourimetry（VC）, were developed for determining the migration amount of FWAs from facial mask to pig skin. In the methods, a self-assembly light source and fluorescence collecting unit was used. The unit can be easily moved and the measurement was very convenient. Some experimental conditions were optimized. The fiber paper migration VC can give semi-quantitative results and was the simplest one in the three methods because collec- tion, separation and detection of the fluorescence were not needed. Both the pig skin migration FS and fiber paper migration FS can give quantitative results and compared with fiber paper migration FS, the pig skin migration FS could give more practical results by simulating the real way of using facial mask. The limits of detection for disodium 4,4＇-bis[（4-anilino-6-hydroxyethylamion-1,3,5-triazin-2-yl）amion]stilbene-2,2＇-disulphonate（VBL） obtained by pig skin migration FS and fiber paper migration FS were 0.03 and 0.05 mg/m2, respectively. 96 kinds of samples were analyzed and the migration amounts of FWAs in 21 kinds of samples were detectable. Correlations between migration amounts obtained by the three methods were very good. Experimental results indicate that the present methods can be applied to the determination of migration amount of FWAs in facial masks.
文摘In this paper,a systematic study about the fluorescence spectrum characteristics of fluorescent whitening agent VBL in solution with the different effects,including the pH and solvent,was conducted.The fluorescence quantum yields in 25 different solvents were measured by the reference of quinine sulfate.According to these a new fluorescence determinations of the VBL in paper was built.The linear regression equation of the method is IF = 0.82 + 6.18 ×107c(mol/L) with a correlation coefficient(r) of 0.9992.The linear range of the method is from 0 to 2.85×10-6g/mL and the detection limit is 9.59×10-9g/mL.
