Morrison Lucas M, Renaud Justin B, Sabourin Lyne, Sumarah Mark W, Yeung Ken K C, Lapen David R
Agriculture and Agri-Food Canada, London Research and Development Centre, London, ON, N5V 4T3, Canada.
University of Western Ontario, Department of Chemistry, London, ON, N6A 5B7, Canada.
J AOAC Int. 2018 Nov 1;101(6):1940-1947. doi: 10.5740/jaoacint.17-0486. Epub 2018 May 21.
: Neonicotinoids are among the most widely used insecticides. Recently, there has been concern associated with unintended adverse effects on honeybees and aquatic invertebrates at low parts-per-trillion levels. : There is a need for LC-MS/MS methods that are capable of high-throughput measurements of the most widely used neonicotinoids at environmentally relevant concentrations in surface water. : This method allows for quantitation of acetamiprid, clothianidin, imidacloprid, dinotefuran, nitenpyram, thiacloprid, and thiamethoxam in surface water. Deuterated internal standards are added to 20 mL environmental samples, which are concentrated by lyophilisation and reconstituted with methanol followed by acetonitrile. : A large variation of mean recovery efficiencies across five different surface water sampling sites within this study was observed, ranging from 45 to 74%. This demonstrated the need for labelled internal standards to compensate for these differences. Atmospheric pressure chemical ionization (APCI) performed better than electrospray ionization (ESI) with limited matrix suppression, achieving 71-110% of the laboratory fortified blank signal. Neonicotinoids were resolved on a C18 column using a 5 min LC method, in which MQL ranged between 0.93 and 4.88 ng/L. : This method enables cost effective, accurate, and reproducible monitoring of these pesticides in the aquatic environment. : Lyophilization is used for high throughput concentration of neonicotinoids in surface water. Variations in matrix effects between samples was greatly reduced by using APCI compared with ESI. Clothianidin and thiamethoxam were detected in all samples with levels ranging from below method quantitation limit to 65 ng/L.
新烟碱类是使用最广泛的杀虫剂之一。最近，人们担心其在万亿分之一水平下会对蜜蜂和水生无脊椎动物产生意外的不利影响。需要采用液相色谱-串联质谱（LC-MS/MS）方法，能够在环境相关浓度下对地表水中使用最广泛的新烟碱类进行高通量测量。该方法可对地表水中的啶虫脒、噻虫胺、吡虫啉、呋虫胺、烯啶虫胺、噻虫啉和噻虫嗪进行定量。将氘代内标添加到20 mL环境样品中，通过冻干浓缩，并用甲醇然后用乙腈复溶。在本研究中，观察到五个不同地表水采样点的平均回收率差异很大，范围为45%至74%。这表明需要使用标记内标来弥补这些差异。大气压化学电离（APCI）的表现优于电喷雾电离（ESI），基质抑制有限，达到实验室加标空白信号的71-110%。使用5分钟的液相色谱方法在C18柱上分离新烟碱类，其中方法定量下限（MQL）在0.93至4.88 ng/L之间。该方法能够对水生环境中的这些农药进行经济高效、准确且可重复的监测。冻干用于高通量浓缩地表水中的新烟碱类。与ESI相比，使用APCI大大降低了样品之间基质效应的差异。在所有样品中均检测到噻虫胺和噻虫嗪，其含量范围从低于方法定量下限到65 ng/L。
