Thorstensen C W, Lode O, Christiansen A L
The Norwegian Crop Research Institute, Plant Protection Centre, Department of Plant Pathology, Hogskoleveien 7, 1432 As, Norway.
J Agric Food Chem. 2000 Dec;48(12):5829-33. doi: 10.1021/jf0000124.
A rapid solid-phase extraction (SPE) method was developed for the determination of bentazone and the phenoxy acids 2,4-D, dichlorprop, MCPA, and mecoprop in Norwegian environmental water samples. Cartridges with a high-capacity cross-linked polystyrene-based polymer were used for off-line preconcentration. The effects of elution solvent, elution volume, sample volume, sorbent mass, pH, and flow rate on the recoveries of the pesticides were investigated using HPLC. Average recovery of >90% was achieved with 500 mg sorbents using 2 mL of methanol with 5% NH3 as elution solvent. The recoveries were independent of sample pH in the tested range of pH 1-7. Using a sample volume of 200 mL, the limits of determination for the phenoxy acids and bentazone are 0.02 microg/L. Sample volumes up to 2000 mL at a flow rate of 60 mL/min could be handled without any loss of analytes, which makes it possible to lower the limits of determination. The SPE method was compared to a routinely used liquid-liquid extraction method. Three different water matrices spiked at 1.0 and 0.05 microg/L were extracted, and the quantification was performed by GC-MS. Both methods permitted the determination of phenoxy acids and bentazone in distilled water, creek water, and well water down to a level of 0.05 microg/L with recoveries >80% for 200 mL samples. Important advantages of the SPE method compared to the liquid-liquid extraction method were the short extraction times, lack of emulsions, use of disposable equipment, and reduced consumption of organic solvents.
开发了一种快速固相萃取（SPE）方法，用于测定挪威环境水样中的苯达松以及苯氧酸类物质2,4-滴、二氯丙酸、灭草灵和甲羧除草醚。采用具有高容量交联聚苯乙烯基聚合物的小柱进行离线预浓缩。使用高效液相色谱法研究了洗脱溶剂、洗脱体积、样品体积、吸附剂质量、pH值和流速对农药回收率的影响。使用500mg吸附剂，以2mL含5%氨的甲醇作为洗脱溶剂，平均回收率>90%。在所测试的pH值1-7范围内，回收率与样品pH值无关。使用200mL样品体积时，苯氧酸类物质和苯达松的测定限为0.02μg/L。在流速为60mL/min时，可处理高达2000mL的样品体积而不会损失任何分析物，这使得降低测定限成为可能。将该固相萃取方法与常规使用的液液萃取方法进行了比较。对添加了1.0和0.05μg/L的三种不同水基质进行了萃取，并通过气相色谱-质谱联用仪进行定量分析。两种方法都能够测定蒸馏水、溪水和井水中低至0.05μg/L的苯氧酸类物质和苯达松，对于200mL样品，回收率>80%。与液液萃取方法相比，固相萃取方法的重要优点是萃取时间短、无乳化现象、使用一次性设备以及减少了有机溶剂的消耗。
