Concentration And Determination Of Ultraviolet Filters In Environmental Water Samples With Microextraction Followed By High Performance Liquid Chromatography

Microextraction is a class of environmentally friendly miniaturized extraction technique. In this paper, two microextraction techniques were developed to concentrate and separate trace amount of emerging ultraviolet filters in environmental water coupled with high performance liquid chromatography(HPLC). This thesis consists of four chapters:Chapter 1: Several sample preparation techniques were briefly introduced including dispersed liquid-liquid microextraction(DLLME), solid phase microextraction(SPME) and single-drop microextraction(SDME). Their extraction mechanisms, advantages and applications were discussed, respectively. Finally, the research interests were proposed and described.Chapter 2: Lauryl alcohol was used as extraction solvent and methanol as disperser solvent to concentrate and determinate ultraviolet filters from environmental water samples with DLLME based on the solidification of floating organic extraction solvent(SOF-DLLME) followed by HPLC. Under optimized conditions, the recoveries ranged from 83.6% to 92.4%. The relative standard deviations were between 6.08% and 9.48%. Their limits of detection ranged from 0.006 to 0.14 ng×mL-1. Satisfactory recoveries and precision were obtained.Chapter 3: Ultrasonic assisted-dispersive liquid-liquid microextraction-high performance liquid chromatography(HPLC)(USA-DLLME-HPLC) method was employed to concentrate and detect UV filters in environmental water samples. This method employed 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide([BMIM]×[TF2N]) as extraction solvent and methanol as disperser solvent. The advantages of this method possess high enrichment, short analysis time. Under optimized conditions, the linearity of UV filters was in the range 0.2-200 ng×mL-1 with corresponding correlation coefficient of 0.9943-0.9992. Their limits of detection ranged from 0.02-0.16 ng×mL-1. The recoveries ranged from 94% to 119%. Satisfactory recoveries and precision were obtained.Chapter 4: Polyaniline(PANI) was electrodeposited onto the surface of etched stainless steel wire(SS) by electrochemical approach to obtained PANI coated SPME fiber(PANI/SS-SPME). Subsequently, the obtained PANI/SS was carbonizated through high temperature. Finally, nitrogen-containing carbon nanoparticles coated solid-phase microextraction fiber(N-CNPs/SS-SPME) was obtained. The new nitrogen-containing carbon nanoparticles coated stainless steel fiber was employed to selectively extract UV filters in environmental water samples coupled with high performance liquid chromatography(HPLC). Under optimized conditions, the linearity of UV filters was in the range 0.02-200 ng·m L-1 with corresponding correlation coefficient of 0.9921-0.9993. The recoveries ranged from 83.6% to 119%. The relative standard deviations of single fiber were between 4.83% and 7.82%(S/N = 3). Their limits of detection and the limits of quantitation ranged from 0.006-0.203 mg·L-1 and 0.02-0.67 ng·m L-1, respectively. The proposed procedure was successfully used for selective concentration and sensitive determination of UV filters in environment water samples.