气相色谱-质谱联用法分析50种农药混合标准品溶液的稳定性

The stability study of standard mixtures containing 50 pesticides for determination of pesticide residues using GC-MS

目的:随着农药多残留分析的快速发展,在一种方法中分析的农药种类达到了数十种甚至数百种,为了有效地降低检验成本,提高试验效率,本文对适用于气相色谱质谱检测的50种农药混合标准品溶液的稳定性进行了考察。方法:采用丙酮、甲苯、乙腈、乙酸乙酯等4种溶剂配制不同浓度的50种农药的混合标准品溶液,在不同的储存条件下放置,每隔一段时间采用气相色谱质谱法进行分析测定。结果:高浓度(约10 ppm)的混合标准品溶液在充氮的条件下,4℃或-18℃条件下避光保存,以甲苯或乙酸乙酯作为溶剂,在3个月内稳定性较好;对于浓度低的混合标准品溶液,大部分农药在甲苯和乙腈中具有良好的稳定性。结论:对于不同的农药混合标准品混合溶液,在合适的浓度、合适的溶剂和合适的保存条件下稳定期可达3～12个月。

Objective：The stability of standard solutions of 50 pesticides for multiclass pesticide residues analysis was studied using GC-MS to effectively reduce testing costs and improve test efficiency.Mehtods：Mixed standard solutions prepared in 4 different concentrations were analyzed by GC-MS at regular intervals.Results：The high concentration（about 10 ppm）of mixed standard solutions in toluene or ethyl acetate stored in dark and in refrigerator（＋4℃ and-18℃） under the condition of nitrogen were in a better stability within 3 months.For the low concentration of mixed standard solutions,the majority of pesticides in toluene and acetonitrile have good stability.Conclusion：Standard mixtures of different pesticides were stable up to 3 to 12 months under conditions of suitable concentration,appropriate solvent and storage conditions.