Medicinal Plants Research Center, Yasuj University of Medical Sciences, Yasuj, Iran.
Department of Polymer Engineering, Golestan University, Gorgan 49188-88369, Iran.
Analyst. 2019 Mar 11;144(6):1923-1934. doi: 10.1039/c8an02338g.
A dispersive micro solid-phase extraction (DMSPE) technique was developed using manganese-oxide nanoparticles loaded on activated carbon (Mn3O4-NPs-AC) as an effective sorbent combined with ultrasound for the extraction and determination of a trace amount of thymol and carvacrol in methanolic extracts of Thymus daenensis, Salvia officinalis, Stachys pilifera, Satureja khuzistanica and mentha, and water samples. Thymol and carvacrol phenolic compounds were extracted from real samples using acetonitrile (ACN) as the desorption solvent. Using central composite design (CCD), the effects of pH, ionic strength (NaCl), nano-sorbent mass, contact time, and desorption volume were investigated. Additionally, based on five-level variables, response surface methodology was used to determine the individual and interactive effects between factors on the process. The optimized extraction conditions included 12 mg of Mn3O4-NPs-AC as the sorbent, 300 μL of ACN as the desorption solvent, pH 3.0, 0.5 w/v% of NaCl, and 4.5 min sonication time. Under the optimized conditions, for all the samples, the limits of detection were 0.054-0.104 ng mL-1 and the limits of quantification were 0.178-0.345 ng mL-1. The correlation coefficients of the calibration curves were >0.985, i.e. in the range of 0.4-6000 ng mL-1. To validate the effects of the matrix, the recovery, reproducibility, repeatability, and overall uncertainty were calculated for the five methanolic extracts, at 50, 100, and 500 ng mL-1. The recovery ranged between 94.5% and 109.0% with a relative standard deviation of <8.0% for the repeatability and reproducibility precision, which strongly supports the favorable repeatability and reproducibility of the method. The presented method also has the excellent sorbent features of NPs for the sorption of the analyte, which is due to the use of ultrasound for dispersion of the material in the sample matrix.
一种分散固相萃取(DMSPE)技术，采用负载在活性炭上的氧化锰纳米粒子(Mn3O4-NPs-AC)作为有效吸附剂，结合超声技术，用于从 Thymus daenensis、Salvia officinalis、Stachys pilifera、Satureja khuzistanica 和薄荷的甲醇提取物以及水样中提取和测定痕量百里香酚和香芹酚。使用乙腈(ACN)作为洗脱溶剂，从实际样品中提取百里香酚和香芹酚酚类化合物。采用中心复合设计(CCD)考察了 pH 值、离子强度(NaCl)、纳米吸附剂质量、接触时间和洗脱体积的影响。此外，基于五水平变量，采用响应面法确定了各因素之间以及各因素之间的相互作用对该过程的影响。优化的萃取条件包括 12mg Mn3O4-NPs-AC 作为吸附剂、300μL ACN 作为洗脱溶剂、pH3.0、0.5w/v%NaCl 和 4.5min 超声时间。在优化条件下，对于所有样品，检测限为 0.054-0.104ng mL-1，定量限为 0.178-0.345ng mL-1。校准曲线的相关系数均大于 0.985，即在 0.4-6000ng mL-1范围内。为了验证基质的影响，在 50、100 和 500ng mL-1 时，对五种甲醇提取物进行了回收率、重现性、再现性和总不确定度的计算。回收率在 94.5%-109.0%之间，重复性和再现性精密度的相对标准偏差(RSD)小于 8.0%，这充分证明了该方法具有良好的重复性和再现性。该方法还具有纳米粒子对分析物的吸附剂的优异吸附剂特性，这是由于超声用于在样品基质中分散材料。
