Mirzajani R, Kardani F, Ramezani Z
Chemistry Department, College of Science, Shahid Chamran University of Ahvaz Ahvaz Iran
Department of Medicinal Chemistry, School of Pharmacy, Ahvaz Jundishapur University of Medical Sciences Ahvaz Iran.
RSC Adv. 2021 Apr 21;11(24):14686-14699. doi: 10.1039/d0ra07674k. eCollection 2021 Apr 15.
In this work, electrospun polyacrylonitrile/reduced graphene oxide-amino-halloysite/bimetallic metal-organic framework (PAN/rGO-amino-HNT/CoZn(MeIm)) nanofiber film was synthesized and investigated as a novel adsorbent for the ultrasonic-assisted thin-film microextraction (UA-TFME) of fatty acid methyl esters (FAMEs), including palmitic methyl ester (PAME), oleic methyl ester (OAME), stearic methyl ester (SAME), and linoleic methyl ester (LAME), from dairy products. The hybrid nanocomposite was obtained bonding halloysite nanotubes to reduced graphene oxide, followed by loading with bimetallic metal-organic frameworks. The determination of FAMEs with nanofiber film was performed in two stages of desorption and absorption where, initially, the analytes were adsorbed onto the nanofiber film and then desorbed with organic solvent. In this study, ultrasound was used for both the adsorption and desorption stages. The advantages of ultrasonication are extensive, overcoming the shortcomings of conventional techniques in terms of energy consumption and solvent use, allowing a shorter treatment time with a low cost of implementation. Based on PAN/rGO-amino-HNT/CoZn(MeIm) thin film, a microextraction-gas chromatography-flame ionization detection (TFME-GC-FID) method was developed. Experimental parameters affecting the extraction and desorption steps were optimized. The desorption parameters, including desorption time and the properties of the desorption solvent, were investigated one factor at a time. Then, effective parameters in the adsorption step were optimized using a Box-Behnken design and Design-Expert 7 software. Under the optimal conditions, the method detection limits (S/N = 3) were in the range of 0.03-0.06 μg L and the limits of quantification (S/N = 10) were within 0.11-0.23 μg L. The relative standard deviations for intra-day and inter-day precision were 2.4-4.7% and 2.6-3.4%, respectively. In the present work, the UA-TFME method was successfully applied for the quantification of fatty acid methyl esters in dairy products (milk, yogurt, cheese, yogurt soda and butter samples) for the first time. The fatty acids were transesterified using standard procedures and were subjected to UA-TFME treatment prior to GC-FID determination. The developed method possesses the advantages of simplicity, rapidity, cost-effectiveness, sensitivity, and non-invasiveness.
在本研究中，通过静电纺丝合成了聚丙烯腈/还原氧化石墨烯-氨基埃洛石/双金属金属有机框架（PAN/rGO-氨基-HNT/CoZn(MeIm)）纳米纤维膜，并将其作为一种新型吸附剂用于乳制品中脂肪酸甲酯（FAMEs）的超声辅助薄膜微萃取（UA-TFME），这些脂肪酸甲酯包括棕榈酸甲酯（PAME）、油酸甲酯（OAME）、硬脂酸甲酯（SAME）和亚油酸甲酯（LAME）。该混合纳米复合材料通过将埃洛石纳米管与还原氧化石墨烯键合，然后负载双金属金属有机框架而获得。使用纳米纤维膜测定FAMEs分解吸和吸附两个阶段进行，首先，分析物被吸附到纳米纤维膜上，然后用有机溶剂解吸。在本研究中，超声用于吸附和解吸阶段。超声处理的优点广泛，克服了传统技术在能耗和溶剂使用方面的缺点，能够以较低的实施成本实现更短的处理时间。基于PAN/rGO-氨基-HNT/CoZn(MeIm)薄膜，建立了一种微萃取-气相色谱-火焰离子化检测（TFME-GC-FID）方法。对影响萃取和解吸步骤的实验参数进行了优化。一次考察一个解吸参数，包括解吸时间和解吸溶剂的性质。然后，使用Box-Behnken设计和Design-Expert 7软件对吸附步骤中的有效参数进行了优化。在最佳条件下，方法的检测限（S/N = 3）在0.03 - 0.06 μg/L范围内，定量限（S/N = 10）在0.11 - 0.23 μg/L范围内。日内和日间精密度的相对标准偏差分别为2.4 - 4.7%和2.6 - 3.4%。在本工作中，UA-TFME方法首次成功应用于乳制品（牛奶、酸奶、奶酪、酸奶汽水和黄油样品）中脂肪酸甲酯的定量分析。脂肪酸采用标准程序进行酯交换反应，并在GC-FID测定之前进行UA-TFME处理。所建立的方法具有简单、快速、经济高效、灵敏和非侵入性等优点。
