| Perfluorinated compounds(PFCs)are compounds that are widely used in non-stick coatings,food packaging materials,surfactants,fire extinguishing foams,etc.They have the properties of thermal stability,chemical stability and water and oil resistance.It exists widely in the environment and shows persistence and bioaccumulation.At present,various PFCs such as PFOA and PFOS have been found in surface water,groundwater,sediment,air dust,and soil,etc,which indicates that they are fully exposed in the environment.Moreover,PFOA(Perfluorooctanoic acid)or PFOS(Perfluorooctane sulfonic acid)can be detected in human blood,urine,and breast milk,even in polar bears.The result of toxicological studies shown that PFCs,which have multiple toxicities such as reproductive toxicity,mutagenic toxicity,developmental toxicity,neurotoxicity,immunotoxicity,et al,are a type of environmental pollutant with systemic multi-organ toxicity.And their biological half-life is very long,which is difficult to be eliminated by metabolism.Relevant studies have shown that PFOS is the main PFCs found in all media in the world.In 2009,PFOA and PFOS were included in the Persistent Organic Pollutants(POPs)list of the Stockholm Convention.Therefore,the detection of PFCs has become a global concern.However,there are many difficulties in the detection of PFCs,especially the background pollution caused by various methods makes accurate detec tion a huge challenge.Solid phase extraction combined with liquid chromatography-tandem mass spectrometry is the most commonly used method to study PFCs.Currently,the reported extraction materials have the disadvantages of high energy consumption,low selectivity and complex operation.Therefore,it is of great research significance to explore extraction materials,which have high selectivity,low cost,rich resources and environmental friendly,and to establish analysis methods with high sensitivity and accuracy.In this paper,a variety of fluorinated biomass adsorbents have been developed using biomass as raw materials.A new method for quantitative analysis of PFCs was established by selecting the fluorinated cedar residue adsorbent with the best adsorption effect and combining with liquid chromatography-tandem mass spectrometry.And applied to the detection of PFCs in lake water samples.The main contents are as follows:1)Preparation of fluorinated biomass adsorbent by fluorosilanization.Using trichloro(1H,1H,2H,2H-tridecafluoro-n-octyl)silane to silanize 7 kinds of biomass materials.Fourier transform infrared spectrometer,X-ray photoelectron spectroscopy and field emission scanning electron microscopy were used to characterize the materials before and after fluorination.The results show that the fluorine silanization modified material contains a large amount of fluorine elements and corresponding functional groups,indicating that the fluorination modification is successful.2)Study on the adsorption effect and extraction conditions of fluorinated biomass materials.The adsorption effect of 8 kinds of fluorinated adsorbents was compared and it was found that the adsorption effect of fluorinated cedar powder was the best.Using fluorinated cedar powder as solid phase extraction material,combined with HPLC-MS/MS to establish a quantitative method for detecting PFCs in water samples.Then,the optimal conditions for the entire extraction process of fluorinated cedar powder to adsorb PFC were explored,and the optimal adsorption conditions were obtained as follows: The adsorbent mass is 200 mg,the extraction time is 8 min,the cleaning solution solvent is 100% pure water,the pH of the extraction solution is 6-7,the desorption solvent is acetone containing 3% TFA(V/V),and the desorption time is 15 min.The adsorption process was explored under optimal conditions,and the maximum adsorption capacity of fluorinated cedar slag was 299.4 μg/g by fitting the adsorption isotherm.3)Fluorinated cedar powder solid phase extraction-liquid mass spectrometry analysis of perfluorinated compounds in environmental samples.The method established in this paper can completely separate 13 kinds of PFCs in only 10 minutes.The linear range of 13 kinds of PFCs is 0.01-100 ng/m L,The detection limit range is 0.001-0.01 ng/m L,the quantification limit range is 0.01-0.05 ng/m L,and the recovery rate is 87.8-112.8%.The results show that the method of separating and enriching PFCs in water samples from fluorinated cedar powder combined with mass spectrometry detection and analysis is reliable.Then use the established method to conduct direct detection and standard addition and recovery experiments on actual water samples.The direct test results showed that none of the 13 PFCs were detected.After standard addition,the recovery rate ranged from 87.8-113.9%,and the RSD ranged from1.4-10.7%.The test results of actual water samples show that the method applied to extract PFC in water samples has the advantages of high selectivity,fast extraction speed,stable and reliable effect,low cost and simple operation. |
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