Rezayat Mohammad R, Jafari Mohammad T, Mohammadipour Leila
Department of Chemistry, Isfahan University of Technology, Isfahan, 84156-83111, Iran.
Heliyon. 2024 Jun 18;10(12):e33230. doi: 10.1016/j.heliyon.2024.e33230. eCollection 2024 Jun 30.
A combination of the dispersive liquid-liquid microextraction (DLLME) method based on the total vaporization procedure and cooling-assisted organic solvent-coated thin film microextraction (TFME) was applied for extracting chlorpyrifos (as the model compound). Based on the high thermal conductivity, a nickel foam thin film with the dimensions of 5.0 mm × 5.0 mm was used as a substrate for holding the organic solvent. Supporting thin film by organic solvent increases the thickness and contact area of the film relative to TFME or single drop microextraction (SDME) alone, resulting in a dramatic increase in the extraction efficiency. To protect the organic solvent and enhance the analyte distribution coefficient between the film and the vapor phase, a cooling system was applied. The proposed design was effective due to condensing the target analyte only on the uniform cooled thin film and not on the other regions in the extraction chamber. A corona discharge ionization source-ion mobility spectrometer was employed to identify the analyte. After optimizing the effective parameters, the limits of quantification (S/N = 10) and detection (S/N = 3) were calculated 0.1 and 0.03 μg L, respectively, and the dynamic range was measured between 0.1 and 7.0 μg L, with a determination coefficient of 0.9997. For three concentration levels of 0.1, 3.0, and 7.0 μg L, the relative standard deviations (n = 3) as the repeatability index were to be 6 %, 5 %, and 4 % for intra-day and 9 %, 6 %, and 5 % for inter-day, respectively. The enrichment factor was also calculated to be 3630 for the analyte concentration of 1.0 μg L. Well water, potato, and agricultural wastewater were analyzed as the real samples and the relative recovery values were measured between 92 % and 99 %. The accuracy of the proposed technique was validated by the European Standards EN 12393 method. In this approach, two steps of analyte extraction (DLLME and TFME) were used consecutively, resulting in better preconcentration and reduced matrix interference during cleaning-up.
基于全蒸发程序的分散液液微萃取（DLLME）方法与冷却辅助有机溶剂涂层薄膜微萃取（TFME）相结合，用于萃取毒死蜱（作为模型化合物）。基于高导热性，使用尺寸为5.0 mm×5.0 mm的泡沫镍薄膜作为承载有机溶剂的基质。通过有机溶剂支撑薄膜相对于单独的TFME或单滴微萃取（SDME）增加了薄膜的厚度和接触面积，从而使萃取效率显著提高。为了保护有机溶剂并提高分析物在薄膜和气相之间的分配系数，应用了冷却系统。所提出的设计是有效的，因为目标分析物仅在均匀冷却的薄膜上冷凝，而不在萃取室的其他区域冷凝。采用电晕放电电离源-离子迁移谱仪对分析物进行鉴定。优化有效参数后，定量限（S/N = 10）和检测限（S/N = 3）分别计算为0.1和0.03 μg L，动态范围在0.1至7.0 μg L之间测定，测定系数为0.9997。对于0.1、3.0和7.0 μg L三个浓度水平，作为重复性指标的日内相对标准偏差（n = 3）分别为6%、5%和4%，日间相对标准偏差分别为9%、6%和5%。对于1.0 μg L的分析物浓度，富集因子也计算为3630。对井水、土豆和农业废水等实际样品进行了分析，相对回收率在92%至99%之间。所提出技术的准确性通过欧洲标准EN 12393方法进行了验证。在这种方法中，分析物萃取的两个步骤（DLLME和TFME）连续使用，从而在净化过程中实现了更好的预浓缩并减少了基质干扰。
