Establishment And Application Of Analytical Method Of 9 Phenolic Pollutants In Water

Phenolic compounds are commonly distributed in the environmental water, many phenols are toxic even at concentration of a few ng/mL, and sample pretreatment is the key element of monitor pollution situation. In this work,6 phenolic priority control pollutants (phenol,3-methylphenol,4-nitrophenol,2,4-dichlorophenol,2,4,6-trichlorophenol, pentachlorophenol) and 3 typical phenolic environmental estrogens (bisphenol A, 4-tert-octylphenol,4-nonylphenol) are selected as target compounds, and a new method based on functional nanofibers solid-phase extraction (SPE) was established for determing 9 phenolics compounds in eviromental water. Furtherly, the new analytical method was applied to detect 9 analytes in 16 main inflow rivers and 6 lake water sampling sites of Taihu Lake. The main content of this work includes 3 aspects as following:1. Optimization of nanofiber for solid phase extraction.Nine target analytes were extracted by carboxylic, polypyrrole (ppy), hydrazine functionalized polyacrylonitrile nanofibers (PAN-NFs) and PAN-NFs without functionalization to compare their performance of extraction. It was turned out that hydrazine functionalized polyacrylonitrile nanofibers (HM-PAN NFs) showed the best adsorption capacity. So HM-PAN NFs with porous morphology were prepared as sorbents through optimization of main preparation condition and mix mode of adsorbents, eventually the proporation of added porous agents (polyvinylpyrrolidone, PVP) were determined as polyacrylonitrile/PVP/dimethylformamide= 10/10/90, and the optimum mix mode of adsorbents were when the mass ration of porous HM-PAN NFs prepared after 3.5h and 5.5h were 3:1. At this condition, the adsorption of 9 phenolic compounds were 92.2%-100.0%, (RSD:0-7.8%, n=3). The SEM results showed that porous structure and bark-shaped protruding could be clearly observed on the surface of porous HM-PAN NFs, and its average diameter were 300nm. The results of FRIR indicated that amino group (-NH2) were successfully introduced into porous PAN-NFs, and the content of amino group were increased as the time of reaction. Additionally, after porous HM-PAN NFs adsorbing 9 phenolic compounds, a new peak showed at 3500-3200cm-1 in the spectrum,suggesting that intermolecular hydrogen bonding were formed between amino group (-NH2) in the NFs and hydroxyl group (-OH) in the phenolic compounds.2. Establishment and assessment of porous HM-PAN nanofibers based detection method for 9 phenolic pollutants.A new method for simultaneous determination of 9 phenolic pollutants in enviomental water samples was developed by porous HM-PAN NFs based solid phase extraction with ultra-high performance liquid chromatography-tadem mass spectrometry (UPLC-MS/MS), excepte phenol was used High Performance Liquid Chromatography-diode array detector for determination, the important parameters affecting extraction efficiency were studied and optimized. Under the optimum condition, the detection limits found for phenol were 0.50ng/mL,3-methylphenol were 0.30ng/mL,4-nitrophenol were 0.030ng/mL,2, 4-dichlorophenol were 0.3ng/mL,2,4,6-trichlorophenol were 0.3ng/mL, pentachlorophenol were 0.030ng/mL, bisphenol A were 0.10ng/mL,4-tert-octylphenol were 0.030ng/mL, 4-nonylphenol were 0.10ng/mL. Satisfactory spiked recoveries of 9 phenolic compounds were 82.4%-111.4%(RSD:3.7%-11.6%, n=6) at three concentration levels in water matrices. By comparing to existing methods, the present method showed advantages in terms of the amount of adsorbent (9.0mg), the consumption of organic solvent (1.5mL), and lower detection limits. Moreover, the proposed method gave good results for phenol which was hard to extracted due to its high polarity as reported, the recovery of phenol using our method could reach 95.7%-106.7%(RSD:4.8%-11.2%, n=6).3. Method application:Concentration analysis of 9 phenolic pollutants in inflow rivers and lake water of Taihu Lake.The concentration levels of 9 phenolics pollutants in lake water and inflow river water of Taihu Lake were evaluated in this chapter. The results showed that top 3 concentration of the total phenolic pollutants in all sampling sites were Zhihugang (47.69 ng/mL), Bridge of wangyuhe (38.29 ng/mL), Bridge of Nanzhaibang (32.34 ng/mL). Among these 9 phenolic pollutants, the detectable rate of phenol was the highest with 81.8%, followed by bisphenol A (54.5%),3-methylphenol (54.5%),2,4,6-trichlorophenol (40.9%),2,4-dichlorophenol (31.8%),4-tert-octylphenol (13.6%), pentachlorophenol (0.045%),4-nitrophenol (0.045%) and 4-nonylphenol (0.0%), respectively. The levels of all the target compounds excepte phenol were lower than the requirements of relevant National Standard. As for phenol, according to Environmental Quality Standards for Surface Water (GB3838-2002) of volatile phenol (calculated by phenol), the water quality in the 22 sampling sites of Taihu showed that 18.2% were at class IV nd 59.1%were at class V.Comparing to Standard method (CJ/T 146-2001), the amount of SPE adsorbents and organic solvent used in our new method were significantly decreased. Our method performed only 10.0mL loading sample volume with simpler and faster SPE process, in the meantime, the detetion limits (0.030-0.50 ng/mL) were lower than Standard method, which is suitable for monitoring 9 target compounds in real water samples. Besides, when applied our method and Standard method to detect same water samples, the difference of two results had no statistical significance (P>0.05), suggesting that the testing results of our method was highly consistant with Standard method.