Tena M T, Valcárcel M, Hidalgo P J, Ubera J L
Department of Analytical Chemistry, Faculty of Sciences, University of Córdoba, E-14004 Córdoba, Spain.
Anal Chem. 1997 Feb 1;69(3):521-6. doi: 10.1021/ac960506t.
Supercritical fluid extraction (SFE) and liquid solvent sonication, in combination with two different sample treatments, were compared for the extraction of natural antioxidants from rosemary leaves. Dried, ground, and sieved rosemary leaves (20 mg) were subjected to SFE with CO(2) at 355 bar at 100 °C (CO(2) density 0.72 g/mL) for 20 min at a liquid flow rate of 4 mL/min. The analytes were concentrated on an ODS trap and subsequently eluted with acetone. Antioxidants in the SF and liquid solvent extract were analyzed by HPLC. Compounds of known antioxidant activity such as carnosol, carnosic acid, and methyl carnosate were identified by mass spectrometry of the HPLC fractions collected. Freezing and grinding the samples in liquid nitrogen resulted in decreased carnosic acid recoveries. Supercritical CO(2) extraction provided the highest recovery of carnosic acid from rosemary leaves (35.7 mg/g), the lowest relative standard deviation (4.4%), and the cleanest extract [Formula: see text] no cleanup prior to HPLC was required. Among the liquid solvents studies, only acetone provided comparable results (73% recovery relative to SC-CO(2) extraction); however, it required decoloration with active carbon prior to HPLC analysis.
比较了超临界流体萃取（SFE）和液体溶剂超声处理，并结合两种不同的样品处理方法，用于从迷迭香叶中提取天然抗氧化剂。将干燥、研磨并过筛的迷迭香叶（20毫克）在355巴、100℃（二氧化碳密度0.72克/毫升）下，以4毫升/分钟的液体流速用二氧化碳进行超临界流体萃取20分钟。分析物在ODS捕集阱上浓缩，随后用丙酮洗脱。通过高效液相色谱法分析超临界流体和液体溶剂提取物中的抗氧化剂。通过对收集的高效液相色谱馏分进行质谱分析，鉴定出具有已知抗氧化活性的化合物，如鼠尾草酸、鼠尾草酚和肉豆蔻酸甲酯。在液氮中冷冻和研磨样品导致鼠尾草酚的回收率降低。超临界二氧化碳萃取从迷迭香叶中获得的鼠尾草酚回收率最高（35.7毫克/克），相对标准偏差最低（4.4%），提取物最纯净[公式：见原文]，高效液相色谱分析前无需净化。在研究的液体溶剂中，只有丙酮提供了可比的结果（相对于超临界二氧化碳萃取的回收率为73%）；然而，在高效液相色谱分析前需要用活性炭进行脱色处理。
