【求助】如何提取水质中的草甘磷和杀虫双

草甘磷用离子交换柱富集。

应助达人

用C18行吗?

楼主，你好！水样中的农药残留可以用液液萃取和固相萃取（离子交换柱富集等）进行富集、萃取、分析测定的方法可以用色谱/质谱法。您可以先说一下实验室的条件，大致想用什么前处理方法和仪器测定方法？

这两种农药的极性都是很大的，水的溶解度很高，离子交换柱比C18柱适用的很。

谢谢了，能分别说下液液萃取和固相萃取的前处理方法吗？我们是准备开展检测，所以想先了解一下再决定用什么方法处理。目前我们有的是water的液相-紫外和荧光检测器，安捷伦的气相ECD和FPD也有。不知用气相可以做吗？如果可以能否发份完整的方法上来。再次感谢！

建议楼主到中国期刊网上或万方数据库或维普数据库中去查相关的检测论文，或许能找到好多方法的介绍。

楼主，你好！草甘膦（glyphosate）的检测方法您可以参考这篇文献：
Improved method for the determination of glyphosate in water
Abstract
A method for the determination of glyphosate (Glyph) and its metabolite aminomethylphosphonic acid (AMPA) in environmental water was developed with the emphasis on the clean-up procedure. The organic compounds in the environmental water were extracted with dichloromethane and the sample was concentrated by rotary evaporation. The concentrated sample was then passed through a strong anion-exchange (SAX) cartridge with an additional 2 ml of resin in the hydroxide form packed above the SAX packing. Glyph and AMPA were eluted with citrate buffer at pH 5.00 and determined directly by high-performance liquid chromatography with a postcolumn reactor and fluorescence detector. The detection limit and average recovery for both components were <2 μg/l and >85%, respectively.

http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TG8-4007C41-53&_user=1915929&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000055340&_version=1&_urlVersion=0&_userid=1915929&md5=2360cd14bdcc2e9163e393de0a9526d9
我下载不了全文，如果您需要全文可以去文献求助应助版求助。

High-performance liquid chromatographic determination of glyphosate in water and plant material after pre-column derivatisation with 9-fluorenylmethyl chloroformate

Abstract
This paper describes a robust and sensitive HPLC method for determination of glyphosate in water and plant material after pre-column derivatisation with 9-fluorenylmethyl chloroformate (FMOC-Cl) using single and coupled polymeric amino columns, respectively. New findings about optimisation of the derivatisation reaction and chromatographic behaviour of glyphosate and AMPA on polymeric amino column are also presented.

The best HPLC conditions for the separation of glyphosate and AMPA in water samples were achieved using a single polymeric amino column and mobile phase at pH 10 which contained 55% (v/v) acetonitrile and 50 mM phosphate buffer. The method was validated by analysing 10 fortified rainwater samples at a level of 1 μg/l. The average recovery was 94% with relative standard deviation (R.S.D.) of 5.4% and the method detection limit of 0.16 μg/l.

The HPLC separation of glyphosate (only) in plant material entailed the coupling of two polymeric amino columns via a switching valve to separate interfering products from the desired analyte. The method was validated using grass samples spiked at the level of 1 mg/kg and gave a method detection limit of 0.3 mg/kg for glyphosate and a recovery of 82.4% with R.S.D. of 10.3%.

http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TF4-4BYRTCR-1&_user=1915929&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000055340&_version=1&_urlVersion=0&_userid=1915929&md5=c3d3a2828d297303458607ca67e0c95f

方法比较麻烦但是绝对可行
草甘膦前处理：取水30ml,用50 mL二氯甲烷进行液液萃取，弃去有机相，利用旋转蒸发仪将水相浓缩至约2 mL，用水定容至3 mL，加入0.3 mL酸性调节液，待净化。称取1.4 g BIO-RAD AG50W-X8 阳离子交换树脂，装入3 mL固相萃取柱。用10 mL去离子水预淋固相萃取柱，弃去淋出液。向固相萃取柱中准确加入0.55 mL上述样品溶液，先用2.5 mL 淋洗液淋洗，弃去淋出液，再用12 mL淋洗液淋洗，收集这12 mL淋出液。淋洗液用旋转蒸发仪在75 °C条件下浓缩至1 mL左右，并且用1 mL淋洗液辅助转移至衍生化试管中，加入5 μL 浓磷酸，平衡1h，80°C氮气吹干。将衍生化试管放置于冰水浴中，然后加入1 mL三氟乙酸酐（TFAA）和0.5 mL三氟乙醇（TFE），在瓶口加上两层聚四氟乙烯材料的生料带，并用聚四氟乙烯材料的瓶盖密封。超声波辅助混合后，在100°C的油浴锅中反应1h。将衍生化后的试管置于凉水中，使其冷至室温。然后常温下氮气吹干，再用10 mL去离子水和60 mL的二氯甲烷进行液液萃取，有机相经2 cm厚的无水硫酸钠层过滤后收集于250 mL圆底烧瓶中。将水相再次用60 mL的二氯甲烷进行液液萃取，有机相经2 cm厚的无水硫酸钠层过滤后合并收集于250 mL圆底烧瓶中。40 °C条件下，旋转蒸发仪中将有机相蒸干，1 mL乙酸乙酯定容，待测。
气相色谱条件：VARIAN gc 3800气相色谱仪，带有氮磷检测器，毛细管柱 （supelco equity-5, 30m×0.25mm ID，膜厚0.25um）及色谱工作站。
进样口温度160 ℃；检测器（NPD）300 ℃；载气为氮气，流速0.3 mL/min。程序升温（初始100 ℃保留1 min，20 ℃/min升至130 ℃，再1 ℃/min升至133 ℃保留10.5 min，最后20 ℃/min 升至150 ℃保留2 min）。
高效液相色谱条件：色谱柱：GL Sciences Inc(250mm×4.6mm,5μm) C18柱；流速：1ml/min；流动相：乙腈：水＝65:35（V/V）；紫外检测波长：207nm；进样量：20μL。