|
Phthalates and PCBs are typical of persistent organic pollutants, which are widely used in industrial production. The two substances are difficult to dissolve in water, fat-soluble and biodegradable, easy to enter the environment in bioaccumulates leading organisms lesions, is a huge threat to the environment and human health. Study the concentration of these two substances in environmental samples is very necessary, due to their content in environmental samples is usually trace levels so required in the pre-analysis of the sample pretreatment. Ultrasound microwave synergistic extraction as a new sample preparation techniques, with fast, efficient, and a small amount of solvent, safe and simple operation. In this paper, ultrasound microwave synergistic extraction technology of phthalates in soil and soles products and PCBs in the soil pretreatment and chromatographic techniques to analyze the determination, the main contents are as follows: 1. Ultrasound microwave synergistic extraction technology of phthalates in soil pretreatment actual soil extract Florisil column purification using gas chromatography analysis determination. Effects of the extraction solvent, microwave power, extraction time on recovery, get the best extraction conditions: hexane / acetone (1:1) as an extraction agent, the amount of solvent 60mL, microwave radiation power is 100W (ultrasonic power fixed at 50W), extraction 12min. Under these conditions, the simulation of soil samples phthalates average recovery of 92.5%. The detection limit of 0.05 ~ 0.16mg/kg, the relative standard deviation (RSD) lt; 5.8%. Compared with direct ultrasound, open microwave extraction, this method has obvious advantages. Methods for the determination of the actual soil samples, the results obtained are the result of the Soxhlet considerable. Ultrasound microwave synergistic extraction technology phthalate plasticizers in 6 different materials sole material pretreatment Florisil column purification using high performance liquid chromatography or gas chromatography - mass spectrometry determination. By Soxhlet extraction method as a standard control, for each sample pretreatment, and using HPLC and GC-MS analysis measurement respectively, and the results were compared and the analysis results show that, between the two methods do not there is a significant difference. Microwave synergistic extraction of ultrasonic extraction agent of choice, as well as the amount of microwave power, extraction time on extraction efficiency. The results show that, when n-hexane - acetone (1:2) as the amount of extractant, extractant 30ml, microwave radiation power of 75W, the extraction time was 10min, the average recovery of phthalates in each sample can reach 77.7 % to 94.0%, to meet the experimental needs. And compared with direct ultrasound, open microwave extraction method, this method has obvious advantages. Ultrasound microwave synergistic extraction technology pretreatment of PCBs in the soil, the actual soil extract Florisil column purification, ready for analysis by gas chromatography. Extraction solvent, microwave power, extraction time on recovery, and the results show that, when to 60m1 mixed solvent of n-hexane - acetone (1:1) as the extraction agent extracted in the a 100W microwave radiation power 9min, two kinds dichlorobiphenyl recovery rate can reach more than 85%. PCB-5 and PCB-11 method detection limit of 0.002 mg / kg and 0.005mg/kg, and the relative standard deviation (RSD) of 4.5% and 5.3%, respectively. Compared with direct ultrasound, open microwave extraction, this method has obvious advantages. Methods for the determination of the actual soil samples, the results obtained are the result of the Soxhlet considerable.
|