| Glyphosate has been widely used in the planting industry to remove various annual and perennial weeds since it was developed by Monsanto in the 1980 s.It has now become the world's most sold and used herbicide product.With the increasing use and scope of glyphosate preparations,people have found traces of glyphosate in more and more natural environments,so the problem of glyphosate pollution has become less and less of concern.Glyphosate is a polar molecule with high water solubility.The negative impact of such chemical properties is not conducive to the extraction of glyphosate.At the same time,glyphosate does not have a chromophore and a fluorescent group.The detector cannot identify it,which adds extra work to the detection and analysis work.At present,the main methods for determining glyphosate include spectrophotometry,gas chromatography,gas chromatography-mass spectrometry,high-performance liquid chromatography-tandem mass spectrometry,and ion chromatography.Most of these methods require solid-phase extraction or liquid-liquid extraction.Glyphosate is extracted,purified,and enriched in the sample,and derivatized with pre-column or post-column,so that glyphosate is derivatized into a product with a chromophore or a fluorescent group.Qualitative and quantitative analysis of the derived product.Indirectly obtain the content of glyphosate.Too many operating steps require a long operating time,which results in the experimental results being susceptible to more interference.At the same time,the experimental reproducibility is poor due to the different operating capabilities of different operators.In order to better detect and analyze glyphosate residues in plant-derived samples and soil,it is urgent to establish a reliable method that is fast to implement,convenient to operate,and accurate in test results.The combination of solvent-induced phase transition extraction and ion chromatography for the detection of glyphosate in plants.The sample was extracted with a 1: 1 mixture of acetonitrile in water and dichloromethane was used as an inducer to induce phase separation in the extract.Glyphosate remained in the layered aqueous layer,and excess non-target substances were recovered to The organic layer completes the enrichment and purification of the target at the same time.The effects of different inducers,the ratio of acetonitrile water and the amount of inducer,and the matrix effects were investigated experimentally.The results show that the combination of solvent-induced phase transition extraction and ion chromatography can be used to conveniently and efficiently determine the content of glyphosate in plant-derived samples.The results showed that the recovery of this method was 98% ~ 105%,and the minimum detection limit was 0.015 mg / L.Based on the above work,the solvent-induced phase transition extraction-ion chromatography was further applied to the detection of glyphosate in soil,and the effects of different inducers,the proportion of acetonitrile water and the amount of inducer on the recovery rate were investigated.The optimized solvent-induced phase transition extraction and ion chromatography were used to detect the content of glyphosate in soil.The measurement results showed that the method showed a high recovery rate,which extended the applicable range of the method.The recovery rate of this method was 99.48% to 101.07%,and the minimum detection limit was 0.015 mg / L.At the same time,a comparative study with national standard methods is conducted.The results show that the biggest advantage of the solvent-induced phase transition method is that the organic phase(acetonitrile layer,containing a small amount of dichloromethane)eliminates excess organic impurities and reduces the influence of the matrix.The aqueous phase does not need to be derivatized,and the sample is directly injected.By reducing the amount of water It can also realize automatic concentration of samples,which can be applied to the detection of glyphosate in plant-derived samples and soil with high efficiency. |
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