Study On The Enrichment Of Trace Compounds By Electromagnet Micro-extraction Technology

In the pretreatment method for the analysis of trace organic compounds in water,solid phase microextraction was widely used in various target analyte enrichment detections.With the development of magnetic materials,magnetic solid phase microextraction technology has also been applied to the analysis of different material enrichments.In this paper,the preparation of magnetic nanomaterials as an extractant was studied for the enrichment analysis of mixed trace organic compounds in water samples.Compared with the addition of permanent magnets to increase the magnetic field separation extractant,this paper also proposed a new extraction method.Electromagnet magnetic solid phase microextraction technology controled the magnetic field to separate the extractant by controlling the power switch.The main contents are as follows:First,polyaniline modified magnetic nanomaterials?Fe₃O₄@Si O₂/PANI?were prepared by modified in-situ surface polymerization method,and characterized by TEM,IR,XRD and XPX.Fe₃O₄@Si O₂/PANI were used as an extractant for the enrichment study of mixed organic acids in water samples.The extractant was separated by a magnetic separation method using an external magnetic field,and an ethanol solution was used as an eluent.The analytes were detected by an ultraviolet spectrophotometer,and the concentration of each component was analyzed by a combined chemometric PLS model.Extraction experimental conditions were optimized.The experimental method was evaluated.The LOD was in the range of 0.8-1?g L^-1,the RSD?n=8?was lower than 4%,the spiked recovery was between 94 and 101%,and the enrichment factor of each component reached 20.Next,graphene modified magnetic nanomaterials were prepared by chemical coprecipitation method and characterized by IR and XPX.It was used as an extractant for the mixing of phthalates for enrichment studies.Electromagnetic magnetic solid phase microextraction technology was used.The enriched solution was detected and analyzed by high performance liquid chromatography.Explored the extraction effects under different extraction conditions and obtained the optimal extraction conditions.The pretreatment enrichment was carried out under the optimal experimental conditions,and the concentration of each component was detected and analyzed.The results showed that the enrichment factor reached 89 and the minimum detection limit was 1?g L^-1.The method has a good extraction effect in a linear range of concentrations of0.01-5 mg L^-1.Finally,the electromagnet magnetic solid-phase microextraction technique was used to further study and apply it to other enrichment detection methods.Fe₃O₄@Si O₂/PANI was used as an extractant to enrich the substance of Sudan Red I in food,and electromagnet magnetic solid phase microextraction was used.The analytes were analyzed by high performance liquid chromatography.Extraction experimental conditions were optimized.The experimental method was evaluated with a minimum detection limit as low as 1?g L^-1 and the spike recovery of 93.6-104.9%.The linear range of Sudan red?concentration in the water sample showed a good linear relationship in0.005-1mg L^-1.The obtained working curve was y=480.84x-0.6974,and the correlation coefficient R was 0.998.The method was applied to the actual sample to test the drinking beverage,and the Sudan Red I substance was not detected.