亚临界水萃取-酶抑制法快速检测蔬菜中的灭多威农药

本文研究了蔬菜中灭多威农药的亚临界水萃取-酶抑制法快速检测技术.研究表明,在萃取温度70℃,萃取时间5 min,提取液的pH为8.0,提取液体积为5 mL的条件下,灭多威有最高萃取效率.将本法分别应用于测定模拟样品和实际样品,结果表明亚临界水萃取的萃取效率和精密度都要高于国家标准方法中的手摇振荡萃取.     

蔬果中12种残留农药的亚临界水萃取研究

利用亚临界水可以定量萃取基质中绝大部分化合物的特点,借助加速溶剂萃取仪(ASE)将亚临界水萃取与固相吸附联用,通过在ASE萃取池中填加C18吸附层的方式改进了萃取吸附模式,优化了萃取温度,研究了亚临界水在萝卜、香瓜、苹果和白菜等蔬果基质中对异稻瘟净等12种农药的萃取效果,用气相色谱-串联质谱法(GC-MS/MS)进行检...     

东北泥炭亚临界—超临界萃取研究

在半连续装置上进行了中国东北几种泥炭非等温亚临界-超临界萃取研究。以甲苯作溶剂时最佳条件是:压力10MPa,温度330—350℃;以甲醇、乙醇作溶剂时最佳条件是:压力10MPa,温度300—320℃。萃取结果表明,生成萃取物的温度范围宽(180—420℃),主要集中在250—320℃温度区。选用灰分低、(H+N-O)/C原子比高的泥炭对萃取有利。动力学处理表明,主要萃取过程可用三级动力学方程描述,表观活化能为50—185KJ/mol。     

亚临界水萃取技术应用于环境样品预处理的研究

对近几年来亚临界水萃取（Sub-critical water extraction,SCWE）技术的研究进行了综述,介绍了亚临界水萃取技术的原理、特点及其在环境分析中的应用。与传统的样品预处理方法和一些新的样品预处理技术（如微波辅助萃取）相比,SCWE可以不使用有机溶剂,对环境造成的污染较小,是一种绿色的样品预处理技术。SCWE在萃取能力、回收率、精密度等方面具有相当的可靠性。方法具有较高的选择性分离预富集某些有机污染物（如多环芳烃等）的特点（引述文献22篇）。     

亚临界水萃取-固相萃取联用技术对沉积物中有机氯农药的萃取研究

研究了用亚临界水萃取-固相萃取(SBwE-SPE)联用技术萃取湖泊沉积物中的有机氯农药。以活性炭纤维作为固相萃取剂,对亚临界水萃取物进行净化处理。在125℃下亚临界水萃取40min,对六氯环己烷(HCH)的四种异构体：(α-HCH,β-HCH,γ-δHCH,-HCH)和六氯代苯(HCB)的萃取回收率在70％～95％之间。该方法具有简单、快捷、只使用少量有机溶剂等优点。     

同时亚临界水萃取与固相萃取从河流沉积物中分离有机氯化合物

静态亚临界水萃取中加入固相萃取剂对河流沉积物中4种有机氯化合物(2-氯酚、2,4,6-三氯酚、五氯酚、六氯苯)进行了同时萃取。与离线亚临界水萃取-固相萃取方法相比,分析物的萃取回收率均有提高,且受亚临界水萃取罐冷却程度的影响较小。以活性炭纤维(ACF)为固相萃取剂,在160℃时,0.050 g的ACF和4.0 mL水对0.500 g的加标沉积物样品中的2-氯酚(2-CP),2,4,6-三氯酚(246-TCP),五氯酚(PCP)和六氯苯(HCB)的萃取效率比离线亚临界水萃取-固相萃取的回收率均有所提高,萃取回收率受萃取罐冷却温度影响较小。方法特别适合于高含量的沉积物样品萃取。该方法与气相色谱检测联用,分析了长江镇江段沉积物中4种有机氯化合物的含量,结果与美国环保署(USEPA)标准方法所得的结果吻合。     

煤中氯在亚临界水条件下的变迁

运用半连续反应装置对山西吴家坪煤和四川华蓥山煤中氯在亚临界水条件下的脱除规律及形态变化进行了研究。考察了反应温度和压力对氯脱除率的影响;同时还运用化学提取法对原煤及残渣中氯的形态进行了研究。研究结果表明,随着反应温度的升高,煤中氯的脱除率也增加,在410℃、15MPa、60min、水流量为580mL/h时,吴家坪煤中氯的脱除率为84.6%,华蓥山煤中氯的脱除率为72.4%。吴家坪煤中氯在15MPa时的脱除率最大。华蓥山煤中氯主要以有机氯的形态存在,而吴家坪煤中氯有8%为离子可交换态的无机氯,其余为有机结合的氯;在亚临界水萃取煤的过程中,离子交换态结合的有机氯比共价键结合的有机氯更容易挥发,有机氯要首先转化为无机氯然后再逸出。     

土壤中不同极性污染物的亚临界水选择性萃取

研究了用亚临界水萃取技术选择性萃取土壤中3种不同极性的污染物:2,4-二氯酚(2,4-DCP)、4-氯联苯(4-PCB)和六氯苯(HCB)。研究了在不同温度下亚临界水对分析物的萃取效率。125℃时,萃取物主要是2,4-DCP;250℃时,主要萃取4-PCB和HCB。同时,研究了亚临界水萃取时间、萃取体积对3种物质的萃取效率的影响,确定了土壤中HCB的最佳亚临界水萃取条件为萃取水体积4mL,萃取时间75m in,萃取温度250℃。本方法用于实际样品中的HCB萃取,通过改变萃取温度,可以去除其它污染物对HCB测定的影响,测定结果与索氏提取-GC分析结果吻合较好。与USEPA标准方法8081A相比,本方法可以显著缩短萃取时间、简化净化步骤及减少有机试剂的用量。     

亚临界水萃取-高效液相色谱法测定聚碳酸酯水杯中双酚A和苯酚的迁移量

建立了亚临界水萃取-高效液相色谱同时测定聚碳酸酯(PC)水杯中双酚A和苯酚迁移量的方法。选择萃取温度120 ℃、萃取压力6.89 MPa(1000 psi)、静态萃取时间1 h、萃取1次对11种样品进行测定。双酚A的迁移量为6.81～11.16 μg/g。5种样品中未检出苯酚,其余样品中苯酚迁移量为3.25～6.08 μg/g。在优化的测定条件下,双酚A和苯酚在8 min内达到基线分离。双酚A和苯酚分别在0.05～20 mg/L和0.02～20 mg/L范围内线性关系良好,相关系数(r)均大于0.9997,检出限分别为7.6 μg/L和2.0 μg/L。日内及日间的重复性(以RSD计)分别小于5.21%及11.63%。传统的浸提法结果表明长时间浸提会使PC材料发生微弱水解。相比传统的浸提法,该方法的萃取效率提高了49～106倍。该方法简便、快速、环保,可用来测定PC水杯中双酚A和苯酚的迁移量。     

亚临界水萃取及气相色谱-串联质谱法检测红茶中多种农药残留

建立了亚临界水萃取及气相色谱-串联质谱(GC-MS/MS)检测红茶中21种有机氯和拟除虫菊酯农药残留的方法。在萃取压力为5 MPa条件下,样品经150 ℃的亚临界水提取15 min后,将目标物转移至丙酮-正己烷(1:1, v/v)中,经ENVI-Carb固相萃取净化小柱净化,DB-5毛细管气相色谱柱分离,在多反应监测(MRM)模式下进行MS/MS检测,基质匹配溶液内标法定量。各目标物在5.0～320.0 μg/L范围内线性关系良好,相关系数均大于0.99,其定量限(信噪比(S/N)＞10)为50 ng/g,检出限(S/N＞3)为10 ng/g。茶叶基质中添加50、100和200 ng/g的标准品时,21种农药的回收率为70.18%～119.98%,相对标准偏差(RSD)为5.01%～11.76%。该方法的灵敏度、准确度和精密度均符合农药残留测定的技术要求,适用于红茶中有机氯和拟除虫菊酯农药残留的检测。     

Subcritical Water Extraction of Salvia miltiorrhiza

In this work, a green extraction technique, subcritical water extraction (SBWE), was employed to extract active pharmaceutical ingredients (APIs) from an important Chinese medicinal herb, Salvia miltiorrhiza (danshen), at various temperatures. The APIs included tanshinone I, tanshinone IIA, protocatechualdehyde, caffeic acid, and ferulic acid. Traditional herbal decoction (THD) of Salvia miltiorrhiza was also carried out for comparison purposes. Reproduction assay of herbal extracts obtained by both SBWE and THD were then conducted on Caenorhabditis elegans so that SBWE conditions could be optimized for the purpose of developing efficacious herbal medicine from Salvia miltiorrhiza. The extraction efficiency was mostly enhanced with increasing extraction temperature. The quantity of tanshinone I in the herbal extract obtained by SBWE at 150 °C was 370-fold higher than that achieved by THD extraction. Reproduction evaluation revealed that the worm reproduction rate decreased and the reproduction inhibition rate increased with elevated SBWE temperatures. Most importantly, the reproduction inhibition rate of the SBWE herbal extracts obtained at all four temperatures investigated was higher than that of traditional herbal decoction extracts. The results of this work show that there are several benefits of subcritical water extraction of medicinal herbs over other existing herbal medicine preparation techniques. Compared to THD, the thousand-year-old and yet still popular herbal preparation method used in herbal medicine, subcritical water extraction is conducted in a closed system where no loss of volatile active pharmaceutical ingredients occurs, although analyte degradation may happen at higher temperatures. Temperature optimization in SBWE makes it possible to be more efficient in extracting APIs from medicinal herbs than the THD method. Compared to other industrial processes of producing herbal medicine, subcritical water extraction eliminates toxic organic solvents. Thus, subcritical water extraction is not only environmentally friendly but also produces safer herbal medicine for patients.     

Isolation of Garlic Bioactives by Pressurized Liquid and Subcritical Water Extraction

Garlic (Allium sativum L.) is widely used in various food products and traditional medicine. Besides unique taste and flavour, it is well known for its chemical profile and bioactive potential. The aim of this study was to apply subcritical water extraction (SWE) and pressurized liquid extraction (PLE) for the extraction of bioactive compounds from the Ranco genotype of garlic. Moreover, PLE process was optimized using response surface methodology (RSM) in order to determine effects and optimize ethanol concentration (45–75%), number of cycles (1–3), extraction time (1–3 min) and temperature (70–110 °C) for maximized total phenols content (TP) and antioxidant activity evaluated by various in vitro assays. Furthermore, temperature effect in SWE process on all responses was evaluated, while allicin content (AC), as a major organosulphur compound, was determined in all samples. Results indicated that PLE provided tremendous advantage over SWE in terms of improved yield and antioxidant activity of garlic extracts. Therefore, high-pressure processes could be used as clean and green procedures for the isolation of garlic bioactives.     

Desulfurization of Morupule Coal with Subcritical Aqueous Ethanol Extraction

Coal combustion greatly contributes to global emissions of toxic gases into the atmosphere, with sulfur emissions as one of the prominent pollutants in addition to carbon dioxide. Nevertheless, Botswana utilizes Morupule''s sub‐bituminous coal with average sulfur and ash contents, as determined in this study being 1.9 and 24.4 % by weight with an average calorific value of 22 MJ Kg⁻¹ to generate electricity. We report an optimized extraction method for reducing total sulfur in Morupule coal from 1.9±0.2 to 0.43±0.02 wt.% at optimum conditions of ethanol/water (90/10, v/v %) at 129 °C (105 bars) in 10 minutes. A Box–Behnken experimental design was employed to select the optimal conditions of temperature (100–180 °C), water proportion in ethanol (10–90, v/v %) and extraction time (10–30 minutes), thus reducing the total sulfur under these mild conditions compared to conventional extraction. The optimized conditions were however not efficient in removing ash.     

黄芩中黄芩苷的亚临界水提取及高效液相色谱分析

建立了黄芩药材中黄芩苷的亚临界水提取 高效液相色谱测定方法。分别考察了温度、压力、提取时间、提取物颗粒度、溶剂比等因素对提取量的影响,并与有机溶剂提取法比较。结果表明,当两者具有相同的提取效果时,亚临界水提取法的提取时间及提取溶剂的消耗量大大减少,避免了使用有机溶剂造成的污染。黄芩苷提取最佳条件为:样品颗粒度80～100目,溶剂比0.2 mL/mg ,5 MPa,130 ℃保持10 min。并通过提取 高效液相色谱联机分析实现了对提取物的实时监测。该技术有望成为从中药材中提取脂溶性成分的有效方法。     

以亚临界水为流动相的高效液相色谱方法的进展

由于纯水在高温高压下形成亚临界液体水时氢键网络发生改变,导致其极性、粘度等物理性质产生较大的变化。以亚临界水为流动相的高效液相色谱方法(SubWC)是近年来发展起来的一种新型分离技术。SubWC的仪器系统可以采用通过改装的一般的气相色谱(GC)或液相色谱(LC)装置;分离色谱柱既可以采用液相色谱填充柱,也可以采用类似于GC的毛细管柱;选择性既可以通过调节柱系统的温度和压力,也可以通过在流动相中添加有机调节剂或盐类进行调节;检测既可用氢火焰离子化检测器检测,也可用紫外检测器检测,极大地拓宽了色谱分离和最佳条件选择的范围。SubWC无论在仪器系统、流动相的洗脱还是固定相的选择等方面均有一定的特征。这种新的分离模式目前尚处于研究与开发阶段,且多用于极性、中等极性样品的快速分离。     

Protein Hydrolysis by Subcritical Water: A New Perspective on Obtaining Bioactive Peptides

The importance of bioactive peptides lies in their diverse applications in the pharmaceutical and food industries. In addition, they have been projected as allies in the control and prevention of certain diseases due to their associated antioxidant, antihypertensive, or hypoglycemic activities, just to mention a few. Obtaining these peptides has been performed traditionally by fermentation processes or enzymatic hydrolysis. In recent years, the use of supercritical fluid technology, specifically subcritical water (SW), has been positioned as an efficient and sustainable alternative to obtain peptides from various protein sources. This review presents and discusses updated research reports on the use of subcritical water to obtain bioactive peptides, its hydrolysis mechanism, and the experimental designs used for the study of effects from factors involved in the hydrolysis process. The aim was to promote obtaining peptides by green technology and to clarify perspectives that still need to be explored in the use of subcritical water in protein hydrolysis.     

亚临界水介质回收酸酐固化环氧树脂/碳纤维复合材料

研究了不同添加剂对碳纤维增强酸酐固化环氧树脂复合材料在亚临界水中降解的影响,通过IR、GC-MS等分析,确定了环氧树脂的分解机理主要为酯键的断裂。 结果表明,KOH与苯酚对酸酐固化环氧树脂的分解没有协同效应,碱性物质更有利于酯键的断裂。 甲基四氢邻苯二甲酸酐固化的环氧树脂增强碳纤维复合材料在反应温度为250 ℃、反应时间为60 min、KOH浓度为0.2 mol/L时可完全分解,回收碳纤维的拉伸强度和表面形貌未受影响。