Cumhuriyet University, Faculty of Sciences, Department of Chemistry, TR-58140, Sivas, Turkey.
Kocaeli University, Faculty of Science and Arts, Department of Chemistry, TR-41380, Kocaeli, Turkey.
Spectrochim Acta A Mol Biomol Spectrosc. 2019 Oct 5;221:117166. doi: 10.1016/j.saa.2019.117166. Epub 2019 May 28.
The aim of our study is to develop a new vortex assisted-ionic liquid dispersive liquid-liquid microextraction (VA-IL-DLLM) method for preconcentration and determination of the quercetin in tea, honey, fruit juice and wine samples by spectrophotometry. The method is based on pH sensitive ion-pair formation between quercetin and rhodamine B at pH 6.5 by donor-acceptor mechanism, and then dispersion of the complex in the fine-drops of ionic liquid (IL). In this context, the effects of pH, concentrations of ion-pairing reagent, the IL, vortex time and dispersive solvent type on the preconcentration process of quercetin were investigated using a 2-level-5-factor central composite half fraction design (CCD) as experimental design for response surface methodology (RSM). Quantitative model was developed to determine the quercetin in food samples, and it is verified by analysis of variance (ANOVA) at a 95% confidence level (P < 0.05). Response surface plots and contour plots obtained by the model are used to determine the interactions of experimental variables. After the optimization, calibration graph was obtained between 35 and 750 μg L with the detection limit of 10.2 μg L. The recovery and relative standard deviations (RSD%) were in range of 94-104%, and in range of 2.5-4.2%, respectively. The accuracy and precision of the method were tested by the experimental studies such as recoveries, intermediate precision, trueness and expanded uncertainty. A comparison of the current results to those reported for other studies is also presented.
本研究旨在开发一种新的涡旋辅助-离子液体分散液液微萃取（VA-IL-DLLM）方法，用于通过分光光度法对茶、蜂蜜、果汁和葡萄酒样品中的槲皮素进行预浓缩和测定。该方法基于在 pH 6.5 下通过给体-受体机制形成槲皮素和罗丹明 B 之间的 pH 敏感离子对，然后将络合物分散在离子液体（IL）的细滴中。在这种情况下，使用 2 水平 5 因素中心组合半分数设计（CCD）作为响应面法（RSM）的实验设计，研究了 pH、离子对试剂浓度、IL、涡旋时间和分散溶剂类型对槲皮素预浓缩过程的影响。建立了用于测定食品样品中槲皮素的定量模型，并通过方差分析（ANOVA）在 95%置信水平（P<0.05）下进行了验证。通过模型获得的响应面图和等高线图用于确定实验变量之间的相互作用。经过优化后，在 35 至 750 μg L 之间获得了校准曲线，检测限为 10.2 μg L。回收率和相对标准偏差（RSD%）分别在 94-104%和 2.5-4.2%的范围内。该方法的准确性和精密度通过回收率、中间精密度、准确度和扩展不确定度等实验研究进行了测试。还提出了将当前结果与其他研究报告的结果进行比较。
