草甘膦(GLY)和草铵膦(GLUF)是非选择性易位除草剂,其用于全世界的农业和非农业土地。GLY和GLUF的广泛使用可能导致它们在土壤中的积累,造成土壤污染,影响土壤微生态环境;累积的GLY和GLUF也通过淋洗迁移到地下水中。然而,GLY,GLUF,它们的代谢物是高度水溶性的,缺乏显色和荧光基团,让他们难以分析。目前,衍生化方法主要用于检测GLY,GLUF,以及它们的代谢物.然而,这些方法也有一些缺点,例如复杂的操作,长时间消费,稳定性差。此外,这些化合物在土壤中很容易钝化和失活;它们也与有机物反应,腐殖酸,金属氧化物,和重金属离子,使它们难以从土壤中提取。迄今为止,GLY的测定方法,GLUF,它们在土壤中的代谢产物是有限的。因此,有必要建立一种快速、灵敏的方法来测定GLY的残留量,GLUF,以及它们在土壤中的代谢产物.在这项研究中,建立了高效液相色谱-串联质谱(HPLC-MS/MS)测定GLY,GLUF,以及它们在土壤中的代谢产物.提取溶剂等参数,提取温度,提取时间,和吸附剂,这影响了提取效率,进行了优化。最后,土壤样品用0.5mol/L的氨溶液在50℃的水浴振荡器中提取,然后以10000r/min离心5min。上清液通过0.2μm注射器过滤器过滤,然后通过HPLC-MS/MS测定。Dikma聚氨基HILIC柱(150mm×2.0mm,5μm)用于色谱分离,峰形良好,目标化合物响应性高。使用含0.07%氨水溶液和乙腈的乙酸铵(0.2mmol/L)作为流动相。洗脱液的流速为0.25mL/min。使用电喷雾电离(ESI)源在多反应监测(MRM)模式下进行MS/MS,并通过外标法使用基质匹配的校准曲线进行定量。所有目标化合物均以负电离模式电离。GLY及其代谢产物的线性范围为5.0~500μg/L,GLUF及其代谢物的含量在2.0至500μg/L之间。线性相关系数大于0.99。分别使用3和10的信噪比(S/N)评估检测限(LOD)和定量限(LOQ)。GLY和(氨基甲基)膦酸(AMPA)的LOD和LOQ值分别为4.0和13.3μg/kg,分别。GLUF的LOD和LOQ值,MPP,N-乙酰草铵膦(NAG)分别为2.0和6.7μg/kg,分别。通过三个加标水平(0.02、0.05、0.2mg/kg)的回收率测试获得方法准确性。在低有机质含量土壤中加标的5个目标的平均回收率为74.2%-101%,相对标准偏差(RSD)为0.93%~6.8%;有机质含量高的土壤加标5个目标的平均回收率为90.8%~116%,RSD为0.40%~7.1%。用所建立的方法测定了桃园中20个土壤样品,和AMPA的检出率,GLY,MPP,GLUF和NAG为45%,25%,10%,5%和5%,分别。最大残留量分别为147、35.2、154、21.6和11.0μg/kg,分别。此方法简单,快速,绿色,便宜,允许在没有有机试剂的情况下进行预处理,并提供高精度,高灵敏度,和良好的重现性。该方法适用于大量不同有机质含量的土壤样品的检测。可为研究土壤中的残留状况和环境行为提供可靠的技术支持。
Glyphosate (GLY) and glufosinate (GLUF) are non-selective translocated herbicides that are used in agricultural and non-agricultural land worldwide. The extensive use of GLY and GLUF may lead to their accumulation in soil, which causes soil pollution and affects the soil micro-ecological environment; the accumulated GLY and GLUF also migrate to groundwater via leaching. However, GLY, GLUF, and their metabolites are highly water-soluble and lack chromogenic and fluorescent groups, making them difficult to analyze. Currently, derivatization methods are mostly used to detect GLY, GLUF, and their metabolites. However, these methods also have some drawbacks, such as complex operation, long time consumption, and poor stability. In addition, these compounds are easily passivated and made inactive in soil; they also react with organic matter, humic acid, metal oxides, and heavy metal ions, making their extraction from soil difficult. To date, the method for the determination of GLY, GLUF, and their metabolites in soil is limited. Therefore, it is necessary to establish a quick and sensitive method to determine the residues of GLY, GLUF, and their metabolites in soil. In this study, a high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was developed for the determination of GLY, GLUF, and their metabolites in soil. Parameters like extraction solvent, extraction temperature, extraction time, and adsorbents, which affected the extraction efficiencies, were optimized. Finally, the soil samples were extracted with 0.5 mol/L ammonia solution in a bath shaker at 50 ℃, and then centrifuged at 10000 r/min for 5 min. The supernatant was filtered through 0.2-μm syringe filters and then determined by HPLC-MS/MS. A Dikma Polyamino HILIC column (150 mm×2.0 mm, 5 μm) was used for chromatographic separation with good peak shape and high response of the target compounds. Ammonium acetate (0.2 mmol/L) with 0.07% ammonia aqueous solution and acetonitrile were used as the mobile phase. The flow rate of the elute was 0.25 mL/min. MS/MS was conducted under multiple reaction monitoring (MRM) mode using an electrospray ionization (ESI) source, and was quantified by the external standard method using matrix-matched calibration curves. All the target compounds were ionized in the negative ionization mode. The linear ranges of GLY and its metabolites were between 5.0 and 500 μg/L, and those of GLUF and its metabolites were between 2.0 and 500 μg/L. Linear correlation coefficients were greater than 0.99. The limit of detection (LOD) and limit of quantification (LOQ) were assessed using signal-to-noise (S/N) ratios of 3 and 10, respectively. The LOD and LOQ values of both GLY and (aminomethyl)phosphonic acid (AMPA) were 4.0 and 13.3 μg/kg, respectively. The LOD and LOQ values of GLUF, MPP, and N-acetyl glufosinate (NAG) were 2.0 and 6.7 μg/kg, respectively. Method accuracy was acquired by recovery test at three spiked levels (0.02, 0.05, 0.2 mg/kg). The average recoveries of five targets spiked in soil with low organic matter content were 74.2%-101%, and the relative standard deviation (RSD) was 0.93%-6.8%; the average recoveries of the five targets spiked in soil with high organic matter content were 90.8%-116%, and the RSD was 0.40%-7.1%. The established method was used to determine 20 soil samples in peach orchard, and the detection rates of AMPA, GLY, MPP, GLUF and NAG were 45%, 25%, 10%, 5% and 5%, respectively. The maximum residues were 147, 35.2, 154, 21.6 and 11.0 μg/kg, respectively. This method is simple, rapid, green, inexpensive, allows pretreatment without organic reagents, and affords high accuracy, high sensitivity, and good reproducibility. The method is suitable for testing a large number of soil samples with different organic matter contents. It can provide reliable technical support for the study of residue status and environmental behavior in soil.