Pesticide Residue Detector for the Determination of Pretreatment Methods for Chinese Medicinal Materials
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Sample extraction Gas chromatography (including GC-MS) - the main method for the analysis of pesticide residues has the advantages of simple operation, high analysis speed, high separation efficiency, and high detection sensitivity. It is suitable for the determination of trace pesticide residues in Chinese herbal medicines. Using gas chromatography, multiple pesticides can be completely separated, quantified and quantified in one injection. At the same time, the high-performance selective detector of gas chromatograph makes the analysis speed of the sample on the pesticide residue detector faster, and the result is more reliable.
Soxhlet extraction method - using a suitable extract in the Soxhlet extractor for continuous extraction for several hours, and then remove the filter residue, the filtrate purification and concentration method. Soxhlet extraction has a good extraction effect and is considered to be a "complete extraction method." Although this method is superior to other methods in terms of recovery rate, extraction efficiency, etc., this method takes a long time, slow speed, and large solvent consumption. The components of Chinese herbal medicines are complex, and there are many complete extractions of interfering substances. At the same time, some pyrethroid pesticides have poor thermal stability. This has a great impact on the entire process of the pesticide residue detector. Therefore, this method is rarely used.
The pre-treatment process of the sample is one of the key steps for the accurate determination of the pesticide residue detector. High-efficiency sample preparation can increase the minimum detection concentration and reduce the influence of impurities on the detection. The sample pretreatment method for the detection of pyrethroid pesticide residues in Chinese herbal medicine by pesticide residue detector is mainly liquid chromatography and gas chromatography, including the combined use of mass spectrometry.