共查询到19条相似文献,搜索用时 171 毫秒
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以硅胶表面接枝有聚乙烯醇(PVA)的接枝微粒PVA/SiO2为固体吸附剂, 对槲皮素和芦丁2种黄酮类化合物进行了吸附研究, 结果表明, 由于接枝微粒PVA/SiO2表面含有高密度的羟基, 使得该接枝微粒与黄酮类化合物分子之间可形成多位点的常规氢键和π型氢键, 溶剂的竞争吸附对黄酮化合物的吸附容量产生很大的影响. 以弱极性的1,2-二氯乙烷(DCE)为溶剂时, 几乎不存在溶剂的竞争吸附, 槲皮素和芦丁具有最高的吸附容量, 分别为0.32 mmol/g(96 mg/g)和0.23 mmol/g(140 mg/g); 而在质子溶剂乙醇中, 强烈的溶剂竞争吸附使两者的吸附容量降至0.22 mmol/g(65 mg/g)和0.14 mmol/g(87 mg/g). 升高温度会减弱氢键作用, 甚至使氢键断裂, 导致吸附容量减小. 质子溶剂中电解质的存在, 对吸附作用产生负性影响. 功能微粒PVA/SiO2对黄酮类化合物的吸附为放热过程, 且为焓驱动的吸附过程. 相似文献
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高效液相色谱法同时检测4种金线莲黄酮苷元及其在提取工艺评价中的应用 总被引:1,自引:0,他引:1
基于高效液相色谱(HPLC)和提取离子流色谱-质谱(EIC-MS),建立了金线莲提取成分定性定量分析及提取效率评价新方法。方法采用20RBAX Ecipse XDB-C18色谱柱,以乙腈-0.03%乙酸水溶液为流动相,采用梯度洗脱,同时分离测定金线莲提取液中芦丁、山奈酚、异鼠李素和槲皮素4种黄酮苷元的含量,经EIC-MS验证,结果可靠。以黄酮提取率为指标,评价酶解-醇提、回流-醇提、搅拌-醇提、超声-醇提、超声-微波-醇提和煎煮6种提取工艺,结果显示,最佳提取工艺为回流-醇提法,提取时间短,醇用量少,总提取率最高,可达14.96mg/g。 相似文献
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采用涡旋混合辅助超声提取样品的前处理方式,应用高效液相色谱法同时测定水基胶中的苯系物和5种邻苯二甲酸酯类增塑剂.基于样品基质的属性,采用漩涡混合器混合样品,使样品均匀分散于萃取溶剂中,再使用超声萃取的方式提取目标物.研究了不同萃取溶剂、提取方式及其条件对目标物检测结果的影响.优选了色谱分析所用的流动相、检测波长、流量和进样量等条件.在优化条件下,5种苯系物和5种邻苯二甲酸酯类增塑剂的峰面积与其质量浓度呈线性关系,相关系数(R2)都大于0.997,回收率分别在91.9%~111.4%和88.3%~121.4%之间,相对标准偏差RSD分别在1.41%~2.80%和1.24%~2.94%之之间.检出限分别在0.3~0.6 mg/kg和0.2~0.3 mg/kg之间.研究表明方法简便、耗溶剂量少、准确,与现行标准方法具有较好的吻合性,适合于同时测定水基胶中的苯系物和5种邻苯二甲酸酯类增塑剂. 相似文献
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利用加速溶剂萃取/气相色谱-质谱联用法建立了同时测定土壤、沉积物和污泥中10种紫外线吸收剂的分析方法。样品采用加速溶剂萃取法提取,提取过程中加入硅胶进行同步净化,提取温度为120℃,提取溶剂为甲醇/二氯甲烷混合溶剂(V/V,50/50),静态循环2次,最后采用气相色谱-质谱联用仪分析检测。10种目标化合物的回收率为70.9%~117%,在土壤和沉积物样品中,大部分目标化合物的LOD<1 ng/g,LOQ<4 ng/g;污泥样品中,大部分目标化合物的LOD<10 ng/g,LOQ<30 ng/g,方法灵敏度高,检出限和定量限都较低。应用此方法检测了土壤、沉积物和污泥的实际样品,结果检出了多种紫外线吸收剂,说明紫外线吸收剂在环境中污染问题不容忽视。 相似文献
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玩具中苯酚和双酚A的高效液相色谱-荧光检测方法研究 总被引:2,自引:0,他引:2
采用高效液相色谱分离,荧光检测器检测,建立了三种不同类型的玩具中苯酚和双酚A的测定方法.用超声提取的方式处理样品,对提取溶剂和提取时间进行选择,确定以甲醇-水(65:35,V/V)作为提取溶液,超声提取20 min.苯酚和双酚A分别在0.012~1.0 mg/L、0.03~2.5 mg/L范围内线性良好,相关系数均达到0.9999,检出限分别为0.6 mg/kg和1.5 mg/kg,不同加标水平的回收率为90.5%~104.3%,其相对标准偏差为0.4%~3.8%.该方法操作简便,灵敏度高、重现性好,能有效提取和测定三类玩具中的苯酚和双酚A. 相似文献
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超声提取/高效液相色谱法测定土壤中的4-壬基酚 总被引:1,自引:0,他引:1
在考察不同提取方法和有机溶剂提取效率的基础上,建立了土壤样品中内分泌干扰物4-壬基酚(4-NP)的超声提取/高效液相色谱(紫外检测器)分析方法。结果显示,以二氯甲烷作提取溶剂时超声提取对土壤中4-NP的提取效率高于索氏提取法;不同有机溶剂的超声提取效率依次为二氯甲烷-甲醇(9∶1)>二氯甲烷>甲醇≈丙酮。样品采用二氯甲烷-甲醇(9∶1)超声提取,经硅胶柱净化、高效液相色谱检测,土壤在4-NP的高、中、低3个加标水平下的平均回收率为91%~94%,相对标准偏差为4.3%~7.2%,方法的检出限为2.0 μg/kg。采用该方法对广东省部分土壤中的4.NP进行检测,得到其含量为5.3~16 μg/kg(干重),低于河北省污水灌溉土壤中的含量。该方法简便快捷、灵敏、重现性好,适用于土壤样品中4-NP的分析。 相似文献
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加速溶剂提取凝胶渗透色谱净化气相色谱质谱快速测定玉米中多环芳烃 总被引:12,自引:2,他引:10
研究了玉米中16种多环芳烃的快速分析方法.采用加速溶剂萃取法(ASE)对玉米样品进行提取,提取溶剂为二氯甲烷,萃取池中依次加入3 g中性氧化铝吸附剂和10 g待测样品,提取的同时能够在线净化除去小分子杂质.收集的提取液进一步用凝胶渗透色谱(GPC)除去样品中大分子油脂和色素,流动相为二氯甲烷,流速为3 mL/min,收集9~13 min的流出液,提取液浓缩定容至1 mL后用GC-SIM-MS进行分析.16种 PAHs以及4种替代物在2个浓度水平添加时的平均添加回收率在55.7%~145.3%之间; RSD为1 4%~16.8%;方法检出限为0.005~0.120 ng/g.本方法简便、快速、准确,净化效果较好,满足残留分析的要求,且能应用于其它谷物样品的日常分析. 相似文献
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组装了一种新型的微波辅助旋转回流装置,该装置的基本原理与微波辅助溶剂萃取的原理相同,但采用了旋转的技术以加速提取.应用该装置以正交实验筛选优化叶下珠中有机酸的提取工艺,并利用毛细管电泳技术分离测定了提取液中有机酸的含量以评价提取效果.最佳提取工艺:乙醚为溶剂,微波功率800 W,提取时间4 min,溶剂用量300 mL.在该提取条件下,平行5次提取叶下珠中丁二酸、原儿茶酸、没食子酸、咖啡酸、阿魏酸的平均含量分别为42.2、103.5、436.2、123.8、67.4 μg/g,相对标准偏差为0.87% ~3.7%,加标回收率为94% ~104%.将该法与常规的微波辅助提取法及回流提取法进行比较,结果表明,微波辅助旋转回流提取法提取效率明显优于其它2种方法. 相似文献
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A new kind of microwave-assisted circumrotation reflux extraction device was constructed and used to study the extraction technology of gallic acid from phyllanthus urmaria L.The extraction principle of the device was same as that of microwave-assisted solvent extraction but using circumrotation techniques as auxiliary stirrer to accelerate the process.Capillary electrophoresis was used to determinate gallic acid in phyllanthus urmaria L extracts in order to evaluate the extraction efficiency of the method.It was found that the most important factors influencing extraction gallic acid were solvent kind and microwave power.The optimum extraction conditions were as follows:water using as irradiate time 4 minute.Under the optimum extraction conditions,five experiments were carried out and the average extraction rate of gallic acid in phyllanthus urmaria L was 4.32 mg/g,relative standard deviations (R.S.D.) was 2.2%.Compared with other extraction methods e.g.reflux extraction and microwave-assisted extraction,better extraction efficiency was observed for the microwave-assisted circumrotation reflux extraction. 相似文献
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高效液相色谱/荧光检测法同时测定高分子材料中6种异氰酸酯 总被引:2,自引:0,他引:2
建立了高分子材料中6种异氰酸酯含量的高效液相色谱/荧光检测法。样品中的异氰酸酯经萃取衍生,C18色谱柱梯度洗脱分离后,以荧光检测器检测,外标法定量。考察了萃取剂、萃取方式、衍生化时间及流动相组成对异氰酸酯萃取量、衍生化效果及分离效果的影响。结果表明,选用极性萃取剂二氯甲烷超声萃取的回收率高于非极性萃取剂环己烷振荡萃取的回收率,最佳衍生化时间为30 min。流动相采用乙腈-三乙胺缓冲液梯度洗脱时,目标组分的分离度高于1.5,在10~100 μg/L范围内异氰酸酯衍生物的线性相关系数不低于0.999 1。高分子样品中异氰酸酯的加标量在0.1~1.0 mg/kg范围内,平均回收率为90%~95%,相对标准偏差(RSD,n=5)为2.2%~4.2%。检出限(信噪比为3)为30.3 ~42.3 μg/kg。实际样品检测结果表明,除苯基异氰酸酯(PI)外的5种异氰酸酯在样品中均有不同程度检出,总含量为79.7~326.3 μg/kg。该方法准确、灵敏、重现性好,适用于高分子材料中异氰酸酯残留量的检测。 相似文献
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Leihong Gao Jing Zou Haihong Liu Jingbin Zeng Yiru Wang Xi Chen 《Journal of separation science》2013,36(7):1298-1303
A method for the quantitative determination of bisphenol A in thermal printing paper was developed and validated. Bisphenol A was extracted from the paper samples using 2% NaOH solution, then the extracted analyte was enriched using single‐drop microextraction followed by HPLC analysis. Several parameters relating to the single‐drop microextraction efficiency including extraction solvent, extraction temperature and time, stirring rate, and pH of donor phase were studied and optimized. Spiked recovery of bisphenol A at 20 and 5 mg/g was found to be 95.8 and 108%, and the method detection limit and method quantification limit was 0.03 and 0.01 mg/g, respectively. Under the optimized conditions, the proposed method was applied to the determination of bisphenol A in seven types of thermal printing paper samples, and the concentration of bisphenol A was found in the range of 0.53–20.9 mg/g. The considerably minimum usage of organic solvents (5 μL 1‐octanol) and high enrichment factor (189–197) in the sample preparation are the two highlighted advantages in comparison with previously published works. 相似文献
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Influence of extraction methods on stability of flavonoids 总被引:1,自引:0,他引:1
Biesaga M 《Journal of chromatography. A》2011,1218(18):2505-2512
The LC-MS/MS was applied for the determination of flavonoids' stability under four types of solvent extraction methods (reflux heating, sonication, maceration and microwave) from maize samples. The 11 flavonoids belong to different groups: flavonols (kaempferol, myricetin, rhamnetin, quercetin, rutin), flavanones (naringenin, naringin, hesperedin), flavones (apigenin, luteolin), isoflavones (genistein) were studied. The effect of the degradation of flavonoids depended on extraction mode and chemical structure. The smallest decomposition was observed by heated reflux extraction procedure within 30 min in water bath and by microwave assisted extraction under 160 W during 1 min. The decomposition for flavonoids depends on number of substituents in flavonoid molecule. The most unstable compound (recovery below 50%) in tested condition was myricetin. The higher number of hydroxyl groups promote degradation of flavonoids, whereas sugar moiety and methoxyl groups protect flavonoids of degradation during microwave and ultrasonic assisted extraction. 相似文献
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A method for PEG‐based microwave‐assisted extraction (MAE) of flavonoid compounds from persimmon leaves has been successfully developed. The extraction efficiency of total flavonoid content was evaluated by the chromatographic peak areas of quercetin and kaempferol, which are two bioactive components typically found in persimmon leaves. The best combination of extraction parameters was obtained with response surface methodology. A microwave power of 525 W, liquid to solid ratio of 17:1 mL/g, and PEG aqueous solution concentration of 60% w/w were identified as the optimum parameters. Extraction dynamics analysis indicated that the quercetin, kaempferol, and total flavonoid contents were rising with increasing extraction time up to 20–25 min, from which point onwards they all decreased. Under the optimum conditions, quercetin, kaempferol, and total flavonoid contents obtained from the sample were 1.20 ± 0.05, 0.64 ± 0.11, and 16.90 ± 0.06 mg/g, respectively. Compared with ethanol‐based MAE, and ethanol‐based and PEG‐based ultrasonic‐assisted extractions, PEG‐based MAE had higher efficiency for the extraction of flavonoid compounds from persimmon leaves. Overall, PEG‐based MAE represents an efficient choice for the extraction of bioactive substances from traditional Chinese medicines. 相似文献
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Dabiri M Salimi S Ghassempour A Rassouli A Talebi M 《Journal of separation science》2005,28(4):387-396
A simple and rapid microwave-assisted extraction (MAE) procedure was developed and optimized for two common color pigments, alizarin and purpurin, in various samples of Rubiaceae plants. Several variables that can potentially affect the extraction efficiency, namely temperature, methanol concentration in the extractant mixture, time, and solvent volume were optimized by means of a central composite design approach. The results suggest that temperature and methanol concentration in the solvent mixture are statistically the most significant factors. The separation and quantitative determination of the pigments was carried out in less than 6 min by a developed high-performance liquid chromatographic method with UV detection at 250 nm. Under optimum operating conditions, MAE showed significantly higher recoveries than those obtained by the conventional extraction methods (ultrasonic and reflux extraction), ranging from 84 to 94%. In addition, a drastic reduction of the extraction time (20 min versus 6 h) and solvent consumption (20 versus 100 mL) was achieved with a reproducibility (RSDs < 10%) comparable with that provided by the reflux extraction as a reference method. 相似文献