1.Self-asembled Gold Nanoparticles Coating for Solid-Phase Microextraction of Ultraviolet Filters in Environmental Water
Haixia LIU ; Yaoxia YANG ; Mingguang MA ; Xuemei WANG ; Xinzhen DU
Chinese Journal of Analytical Chemistry 2015;(2):207-211
Self-assembled gold nanoparticles ( AuNPs) coating was fabricated using an etched stainless steel wire as a support on which AuNPs were first deposited, then after modified with mercaptan, another layer of AuNPs was self-assembled. The AuNPs modified stainless steel wire was used in solid phase microextraction (SPME) coupled with high performance liquid chromatography (HPLC) for the determination of ultraviolet ( UV) filters in environmental water. The best extraction efficiencies were achieved within 30 min at 55℃ and at pH 7 with stirring rate of 800 r/min. Under the optimized conditions, the established AuNPs-SPME-HPLC method for the determination of UV filters benzophnone-3 ( BP-3 ) , 2-ethylhexyl-4-( N, N-dimethylamino ) benzoate ( OD-PABA) , 2-ethylhexyl-4-trimethoxycinnamate ( EHMC) and 2-ethylhexyl salicylate ( EHS) was linear in the range of 0. 004-200 μg/L. The limits of detection of the method were 0. 43-570 ng/L ( S/N=3 ) . The relative standard deviation ( RSD ) of AuNPs-SPME-HPLC was 1 . 9%-4 . 2% ( n=5 ) for spiked water samples of 20 μg/L each UV filter. In the case of real water samples analyses, the recoveries of spiked UV filters were 77 . 9%-108% with RSDs of 3 . 1%-8 . 0% ( n=5 ) .
2.On-line Quantitative Monitoring and Control of Tobacco Flavors by Near Infrared Spectroscopy Combined with Advanced Calibration Transfer Method
Xinzhen SHI ; Zhiguo WANG ; Wen DU ; Hao YI ; Juan ZHANG ; Zengping CHEN ; Ruqin YU
Chinese Journal of Analytical Chemistry 2014;(11):1673-1678
Whennearinfraredspectroscopyisappliedtoon-linemonitoringandcontroloftobaccoflavors,the variation in temperature can severely deteriorate the predictive performance of near infrared spectroscopic calibration models and results in a significant increases of the root mean square error value for the main constituents in syrup samples from 2. 4% to 29. 0%. In this paper, near infrared spectroscopy has been incorporated with an advanced calibration transfer method-loading space standardization to effectively eliminate the deteriorate effects of temperature variation on quantitative results and finally realize the fast and accurate on-line quantitative monitoring and control of tobacco flavors. The root mean square error value for the main constituents in syrup samples is successfully retained at a satisfying low level of 3 . 8%. The results of this paper will provide technical support for the preparation, preservation and use of tobacco flavors, and realize on-line process quality control of cigarettes.