| In the thesis,the self-assembled fluorescence measurement system and self-developed commercial fluorescent whitening(FWA)instrument were used to detect the FWA and analyze paper notebook,facial mask,washing product,napkin,and sanitary towel samples.Light emitting diode(LED)fluorescence spectrophotometer(FS)was used to detect the fluorescent whitening agent(FWA)in the paper notebook used by primary and middle school students and facial mask samples.Based on the experimental results obtained in the primary investigations,an instrument for rapidly detecting FWAs was developed.The standards and detection methods for the developed instrument were established and the instrument was used to investigate the content and migration amount of FWAs in washing product,napkin and sanitary towel.The self-assembled fluorescence measurement system based on LED was developed.The measurement system consisted of three LEDs with 365 nm ultralight brightness,two lenses,an optical fiber,and a fluorescence spectrophotometer.The light emitted from the LEDs irradiated the sample.The FWA in the sample can emit fluorescence and the emitted fluorescence passed a lens to make the light focus on the entrance of the fiber.The fluorescence passed through the fiber and entered the fluorescence spectrophotometer,where the fluorescence was separated and measured.The effects of the LED number,the applied current of the LED,the distance between the LED and the sample were investigated.Based on the developed measurement system and under optional instrumental conditions,the two methods,including finger migration fluorescence spectrophotometry(FS)and paper migration FS,were established for measuring the migration amount of FWAs in the paper notebooks.The limits of detection for finger and paper migration FS were 0.12 and 0.07 mg/m2,respectively.Thirty practical paper notebook samples were analyzed for the FWA migration amount.For the purpose of comparison,the European standard method was also applied to the determination of the FWA migration amount in the samples.The correlation of the analytical results obtained by the present methods with those obtained by European standard method was satisfactory.The present methods have some advantages,such as stability and repeatability of analytical results,no requirement of sample pretreatment,and on-site measurement and can be applied to the measurement of migration amount of FWAs in paper notebooks used by students.Based on the fluorescence measurement system mentioned above three methods,including pig skin migration FS,fiber paper migration FS,and fiber paper migration visual colorimetry(VC)were developed for determining the migration amount of FWAs in facial mask.The analytical performances of the developed methods were evaluated.The effects of sample temperature and migration time were investigated.The FWA migration amount increased with the increase of the sample temperature and when the migration time was longer than 20 min,the migration amount was unchanged.The fiber paper migration VC can give semi-quantitative results and was the simplest one in the three methods because collection,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 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.Correlation between migration amounts obtained by three methods was very good.Experimental results indicated the present methods can be applied to the determination of the migration amount of FWAs in facial masks.An instrument of on-site rapidly detecting FWAs based on the front-face fluorescent technique was developed using ultralight brightness LED as excitation light source.The instrument consisted of an excitation light source,a power supply controller,a spectral probe,a detector,a signal amplifier,and signal treatment and storage unit.The content and migration amount of FWAs can be determined on condition that Bluetooth 4.0 transmission unit,IOS and android shower and APP soft ware were used.The effects of LED number,incident angle between the LED excitation light and the normal line of the sample surface,wavelength resolution,distance between LED and sample,irradiation diameter of sample,and LED applied current on the fluorescence intensity of FWAs were examined.The optical simulation of spectral probe was performed.The analytical methods for different samples were established by analyzing a large amount of the samples.The performance index and detection method were examined to provide the data for establishing the instrumental standard.The standard of FWA on-site rapid detection instrument was established based on the experimental results obtained with five commercial FWA rapid detection instruments.The standards and detection methods of the performance indexes,such as accuracy,repeatability,linear range,stability,detection time,applied current,dielectric strength and appearance were established under the conventional conditions.The difinition of technical terms,detection method and technologic mark,package,transport,storage of the instrument were stipulated.The established standard is the quality guarantee of commercial FWA rapid detection instrument.The self-developed FWA rapid detection instrument was used to determine the migration amount of FWA in washing products.The glass fiber paper was used as the adsorbent.The FWAs in washing products can adsorb onto the adsorbent.The adsorbent was directly measured with the developed instrument.The effects of adsorbent type,soak period,soak temperature,and other coexisting substances on fluorescence intensity were examined.The linear range for the determination of the FWAs was 10.0-500.0 ?g/kg and the limit of detection was 2.8 ?g/kg.Ninety-six kinds of washing products were analyzed and the migration amounts of the whitening agents in 12 kinds of the washing products were detectable.The correlation of analytical results of the 96 samples obtained by the present method with these obtained by the visual colorimetry was satisfactory.The present method was simple,rapid,and accurate and can be applied to the determination of the migration amount of the FWAs in the washing products.The analytical time was 40 min.The self-developed instrument was used to determine the migration amount of FWAs in the napkin and sanitary towel.The gauze and pig skin were used as adsorbents of FWAs in the napkin and sanitary towel,respectively.The napkin and sanitary towel standard samples containing FWA were prepared.The effects of water content in gauze and drying time of gauze on fluorescence intensity were investigated.Under optimal conditions,the limit of detection and linear range for determining FWA migration amount in the napkin were 0.5 mg/m2,and 1.7-362.8 mg/m2,and those for determining FWA migration amount in sanitary towel were 0.03 mg/m2 and 0.1-12.0 mg/m2,respectively.The present method was applied to the analysis of 85 kinds of napkin samples and 104 kinds of sanitary towel samples to determine the FWA migration amount in the samples.The present method has some advantages in sample treatment,practical application,and analytical time.The total analytical time only needed 10 min. |
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