Department of Chemistry, Iowa State University, 1605 Gilman Hall, Ames, IA 50011 USA.
Restek Corporation, 110 Benner Circle, Bellefonte, PA 16823, USA.
J Chromatogr A. 2022 Sep 13;1680:463416. doi: 10.1016/j.chroma.2022.463416. Epub 2022 Aug 10.
The high abundance of cannabinoids within cannabis samples presents an issue for pesticide testing as cannabinoids are often co-extracted with pesticides using various sample preparation techniques. Cannabinoids may also chromatographically co-elute with moderate polarity pesticides and inhibit the ionization of pesticides when using mass spectrometry. To circumvent these issues, we have developed a new approach to isolate commonly regulated pesticides and cannabinoids from aqueous samples using tunable, crosslinked imidazolium polymeric ionic liquid (PIL)-based sorbent coatings for direct immersion solid-phase microextraction (DI-SPME). The selectivity of four PIL sorbent coatings towards 20 pesticides and six cannabinoids, including cannabidiol and Δ-THC, was investigated and compared against a commercial PDMS/DVB fiber. Extraction and desorption conditions, including salt content, extraction temperature, pH, extraction time, desorption solvent, and desorption time, were optimized using high-performance liquid chromatography (HPLC) with ultraviolet (UV) detection. Under optimized conditions, the PIL fiber consisting of 1-vinylbenzyl-3-octylimidazolium bis[(trifluoromethyl)sulfonyl]imide ([VBIMC][NTf]) and 1,12-di(3-vinylbenzylimidazolium)dodecane dibis[(trifluoromethyl)sulfonyl]imide ([(VBIM)C]2[NTf]) sorbent coating provided the best selectivity towards pesticides compared to other PILs and the PDMS/DVB fibers and was able to reach limits of detection (LODs) as low as 1 µg/L. When compared to a previously reported PIL-based SPME HPLC-UV method for pesticide analysis, the amount of cannabinoids extracted from the sample was decreased 9-fold while a 4-fold enhancement in the extraction of pesticides was achieved. Additionally, the PIL-based SPME method was applied to samples containing environmentally-relevant concentrations of pesticides and cannabinoids to assess its feasibility for Cannabis quality control testing. Relative recoveries between 95% and 141% were obtained using the PIL sorbent coating while recoveries ranging from 50% to 114% were obtained using the PDMS/DVB fiber.
大麻样本中大麻素的高丰度给农药检测带来了一个问题，因为大麻素通常与各种样品制备技术一起与农药共提取。大麻素也可能与中等极性的农药共洗脱，并在使用质谱时抑制农药的离子化。为了解决这些问题，我们开发了一种新的方法，使用可调谐交联咪唑基聚合离子液体（PIL）基吸附剂涂层从水性样品中分离常见的受监管的农药和大麻素，用于直接浸入式固相微萃取（DI-SPME）。研究了四种 PIL 吸附剂涂层对 20 种农药和 6 种大麻素（包括大麻二酚和 Δ-THC）的选择性，并与商业 PDMS/DVB 纤维进行了比较。使用高效液相色谱（HPLC）与紫外（UV）检测优化了萃取和解析条件，包括盐含量、萃取温度、pH 值、萃取时间、解析溶剂和解析时间。在优化条件下，由 1-乙烯基苄基-3-辛基咪唑双（三氟甲基磺酰基）亚胺([VBIMC][NTf])和 1,12-二（3-乙烯基苄基咪唑）十二烷双（三氟甲基磺酰基）亚胺([(VBIM)C]2[NTf])吸附剂涂层组成的 PIL 纤维与其他 PIL 和 PDMS/DVB 纤维相比，对农药具有最佳的选择性，并且能够达到低至 1µg/L 的检测限（LOD）。与之前报道的基于 PIL 的 SPME HPLC-UV 农药分析方法相比，从样品中提取的大麻素量减少了 9 倍，而农药的提取量提高了 4 倍。此外，还将基于 PIL 的 SPME 方法应用于含有环境相关浓度的农药和大麻素的样品中，以评估其用于大麻质量控制测试的可行性。使用 PIL 吸附剂涂层获得了 95%至 141%的相对回收率，而使用 PDMS/DVB 纤维获得了 50%至 114%的回收率。
