高效液相色谱-化学发光法测定人血清及动物组织中的己烯雌酚

基于己烯雌酚在酸性介质中对Ce(Ⅳ)和Rh6G的化学发光体系的增敏作用,建立了人血清及动物组织中己烯雌酚的高效液相色谱/化学发光检测方法。色谱柱为Welchrom-C18柱(4.6 mm×250 mm,5μm),流动相为甲醇-水(75:25,V/V,pH6.0)。己烯雌酚在1.0×10-8～2.5×10-6g/mL范围内呈良好线性,在优化的实验条件下最低检出限为3.0×10-9g/mL。对5.0×10-7g/mL的己烯雌酚进行11次平行测定,其相对标准偏差为2.1%。     

薄层荧光扫描法测定花生根中白藜芦醇的含量

在硅胶G铝箔板上,以V(氯仿):V(丙酮):V(甲酸)=8:1:0.2的溶液为展开剂,狭缝尺寸为3mm×0.45mm,检测波长为335nm,采用薄层荧光扫描法测定花生根中白藜芦醇的含量.结果表明:白藜芦醇在21.6～108.0ng范围内线性关系良好,回归方程为Y=-664.701+12.666X,R=0.9969,花生根中白藜芦醇的含量为358.89μg/g.     

β-环糊精和青霉素V钾包络物荧光性能的研究

用荧光光谱法对水溶液中β-环糊精(β-CD)和青霉素V钾(PMPP)包络反应的光谱行为进行了研究,利用改进的Benesi-Hildebrand法测定了包络物的形成常数.提出了测定PMPP的高灵敏度荧光分析新方法,在最大激发波长236.0nm、最大发射波长308.0nm处,PMPP在8.0×10-10~3.2×10-6 g/mL范围内与荧光强度呈良好的线性关系,相关系数为0.993 5,方法检出限为1.8×10-10 g/mL,相对标准偏差为1.1%(n=5,c=4.0×10-8g/mL).用该法测定片剂中PMPP的结果令人满意,回收率为99.9%~100.4%.     

Ce(Ⅳ)-罗丹明6G化学发光体系与毛细管电泳联用同时测定氯丙嗪和异丙嗪

提出了一种毛细管电泳化学发光联用技术同时测定氯丙嗪和异丙嗪。在酸性条件下,氯丙嗪和异丙嗪能被Ce(Ⅳ)氧化,然后将能量转移给荧光发射体-罗丹明6G,并以化学发光形式释放能量。基于此,结合流动注射技术,以10 mmol/L KH2PO4/H3PO4(pH3.5)为运行缓冲液,实现了两种药物的分离。方法的线性范围分别为4.0×10-8~2.0×10-6g/mL和2.0×10-8~2.0×10-6g/mL,检出限分别为5.6 ng/mL和3.4 ng/mL,对2.0×10-6g/mL异丙嗪平行测定了9次,相对标准偏差为2.8%。方法可用于同时测定人血清中的氯丙嗪和异丙嗪。     

纳米金催化鲁米诺化学发光体系测定甲巯咪唑

在碱性介质中,甲巯咪唑能强烈增敏纳米金-鲁米诺-硝酸银化学发光体系产生较强的化学发光信号,据此建立了一种流动注射化学发光测定甲巯咪唑的新方法。在优化实验条件下,该方法对甲巯咪唑的检测线性范围为1.0×10-9~1.0×10-8、1.0×10-8~1.0×10-7、1.0×10-7~1.0×10-6g/mL,检出限(S/N=3)为3.0×10-10g/mL,相对标准偏差为1.2%(n=11,ρ=1.0×10-8g/mL)。将该法用于药物中甲巯咪唑含量的测定,结果满意。同时,采用化学发光光谱表征技术对该体系的化学发光反应机理进行了初步探讨。     

一次性碳质膜电极电化学发光测定铅(Ⅱ)

基于在一次性碳质膜电极上铅(Ⅱ)与7-I-8-H2QS-5-磺酸形成的配合物对鲁米诺弱的电化学发光有强烈的增敏作用,建立了一种测定铅(Ⅱ)的电化学发光新方法。在最佳的实验条件下,该法的线性范围为2.0×10-8~2.0×10-6g/mL,检出限为6.0×10-9g/mL,相对标准偏差为4.8%[ρ(Pb)=2.0×10-7g/mL,n=11]。     

NCS-核黄素-盐酸曲普利啶化学发光反应及其分析应用研究

以荧光试剂核黄素为化学发光试剂,构建了N-氯代丁二酰亚胺(NCS)-核黄素-盐酸曲普利啶化学发光新体系。利用此体系建立了测定盐酸曲普利啶的化学发光分析新方法,方法的线性范围为1.0×10-8～9.0×10-7g/mL,检出限为8×10-9g/mL,对浓度为1.0×10-7g/mL盐酸曲普利啶溶液进行11次平行测定的相对...     

流动注射-化学发光方法测定盐酸萘甲唑林和盐酸氧甲唑林

H2SO4酸性条件下,甲醛对KMnO4-盐酸萘甲唑林(盐酸氧甲唑林)化学发光体系有较强的增敏作用,且强度与药物浓度呈良好的线性关系.据此,建立了采用KMnO4-甲醛体系测定制剂中盐酸萘甲唑林(盐酸氧甲唑林)的流动注射-化学发光分析法.在优化的实验条件下,盐酸萘甲唑林在1.0×10-8～7.0×10-6g/mL范围内呈良好的线性关系,检出限为8.69×10-9g/mL;盐酸氧甲唑林在5.0×10-8～1.0×10-5范围内呈线性关系,检出限为3.47×10-8g/mL.对浓度为1.0×10-6g/mL的盐酸萘甲唑林和盐酸氧甲唑林分别进行的11次平行测定,RSD分别为4.0%和4.1%.     

氟喹诺酮类抗菌素-钯(Ⅱ)-曙红Y体系的共振瑞利散射光谱及其分析应用

在pH值为4.1~5.0的Britton-Robinson(BR)缓冲溶液中,环丙沙星(ciprofloxacin,CPF)、诺氟沙星(norfloxacin,NRF)、氧氟沙星(ofloxacin,OFL)、左氧氟沙星(levofloxacin,LVF)等氟喹诺酮类抗菌素(fluoro-quinolone derivatives,FQs)与Pd(Ⅱ)反应形成无色阳离子螯合物,当其与曙红Y反应形成三元离子缔合物,共振瑞利散射(RRS)均显著增强,并产生新的RRS光谱,最大RRS峰均位于368nm处。在一定范围内FQNs的浓度与RRS强度(ΔI)成正比,4种抗菌素的线性范围和检出限分别为0~2.4×10-6g/mL和9.4×10-9g/mL(CPF);0~2.4×10-6g/mL和12.8×10-9g/mL(NRF);0~2.2×10-6g/mL和16.2×10-9g/mL(LVF);0~2.8×10-6g/mL和15.6×10-9g/mL(OFL)。并具有较好的选择性,用于针剂、鸡血清中诺氟沙星的测定时,其回收率在95.0%~101.5%。建立了一种灵敏、简便、快速测定喹诺酮类抗菌素的新方法。     

偶合反应化学发光法测定过氧化苯甲酰

基于过氧化苯甲酰可以氧化K4Fe(CN)6生成K3Fe(CN)6,生成的K3Fe(CN)6在碱性溶液氧化鲁米诺可产生强的化学发光的特性,建立了测定过氧化苯甲酰的偶合反应化学发光新方法.该方法测定过氧化苯甲酰的线性范围为1.0×10-8～4.0×10-6 g/mL, 检出限为5×10-9 g/mL,相对标准偏差为3.0% (1.0×10-7 g/mL过氧化苯甲酰溶液,n=11).该方法已用于市售面粉中过氧化苯甲酰的测定.     

Trans‐Resveratrol Extraction from Grapevine: Application to Berries and Leaves from Vines Affected by Esca Proper

Abstract

Trans‐resveratrol is a metabolite involved in resistance of plants during biotic and abiotic stress. Here we report the optimization of a rapid solvent extraction protocol and its application to different parts of grapevines. We also demonstrate the influence of sample pretreatment with liquid nitrogen on trans‐resveratrol stability, which results as the key step in avoiding oxygen degradation during solvent extraction. Up to 94% of trans‐resveratrol was recovered using this procedure. Berries and leaves from healthy and symptomatic, esca proper–affected vines collected at two different phenological growth stages were analyzed. Trans‐resveratrol was determined in berry and leaf samples; symptomatic vines always showed a significantly higher amount with respect to healthy vines. The mean concentration of trans‐resveratrol in berries was 0.93 µg/g_dm and 1.92 µg/g_dm at veraison and 1.49 µg/g_dm and 2.72 µg/g_dm at harvest from healthy and symptomatic vines, respectively.     

大孔吸附树脂结合酶解法分离纯化虎杖中白藜芦醇的研究

研究了大孔吸附树脂结合酶解法提取和纯化虎杖中白藜芦醇的方法,采用HPLC法测定虎杖中白藜芦醇的含量,考查了β-糖苷酶对虎杖药材酶解前后白藜芦醇含量的变化,并经静态吸附考察了4种树脂,最后确定以H1020作为提取分离白藜芦醇的树脂.此树脂吸附量较高,脱附容易,有利于得到质量较好的白藜芦醇产品,经该树脂吸附解吸,饱和吸附量可达51.4mg/g,解吸率达92.5%.大孔树脂分离纯化白藜芦醇的含量可达71.5%,而上柱前粗提物中白藜芦醇含量为8.71%,说明采用本法分离纯化虎杖中白藜芦醇是可行的.     

Determination of resveratrol and piceid in beer matrices by solid-phase extraction and liquid chromatography-tandem mass spectrometry

Beer is one of the most commonly consumed undistilled alcoholic beverages in many countries. In recent studies, the stilbenes resveratrol and piceid have been found in some hop varieties which are used in the production of beer. Therefore, they could be transferred to beer. The aim of the present work was to validate a method to study the potential content of trans- and cis-resveratrol and piceid in 110 commercial beers from around the world. The resveratrol and piceid contents of 110 beers were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) after a solid-phase extraction (SPE) using optimized and validated procedures for the beer matrix. The beer matrix effect was also studied. Stilbenes were found in quantifiable amounts in 92 beers, while concentrations below the limit of quantification (LOQ) were found in 18 beers. Resveratrol was found in the range of 1.34-77.0μg/L in 79% of the beers analyzed, and piceid was found in the range of 1.80-27.3μg/L in only 33% of them. The mean of total resveratrol in all the beers was 14.7±20.5μg/L. The content of resveratrol has been compared with other resveratrol containing foods. A serving of beer contains similar amounts of stilbenes as berries, less than chocolate and grape products but more than pistachios, peanuts or tomatoes. Overall, beer is one of the products with the lowest levels of total resveratrol (μg/L), and despite its high consumption it should not be considered as a representative source of resveratrol.     

液相微萃取-高效液相色谱法分析葡萄汁中多酚类化合物

建立了一种基于液相微萃取与高效液相色谱联用技术测定葡萄汁中鞣花酸、白藜芦醇和槲皮素的分析方法. 比较了单液滴液相微萃取和中空纤维液相微萃取两种萃取模式, 选择了单液滴液相微萃取作为3种多酚类化合物的液相微萃取模式. 考察了搅拌速度、萃取时间、料液相pH和料液相离子强度的影响. 鞣花酸、白藜芦醇和槲皮素的富集倍数分别为48.4、 79.4和155.8, 方法的线性范围为0.0050～5.0 μg/mL, 鞣花酸、白藜芦醇和槲皮素的检出限分别为0.015, 0.0020, 0.0080 μg/mL, 相对标准偏差分别为2.0%, 1.8%和1.7%. 用于实际样品葡萄汁的分析, 加标回收率在81.9%～102.3%之间.     

Supercritical fluid extraction of resveratrol from grape skin of Vitis vinifera and determination by HPLC

Supercritical fluid extraction of resveratrol from grape skin of Vitis vinifera was studied. Extraction variables such pressure, modifier concentration (ethanol), and extraction time were optimised. Final extraction conditions were: 40 degrees C, 150 bar, 7.5% ethanol and extraction time 15 min. Extraction recovery and precision (variation coefficient between 0.2 and 1.0%) were calculated. The resveratrol content in the ethanolic extract was determined by HPLC with UV detection at 306 nm. Acetic acid-methanol-water was used as the mobile phase, and C-18 and C-8 columns were tested, instrumental parameters were optimised, and analytical parameters were calculated (lineal interval 0-75 mg l(-1), detection limit 0.1 mg l(-1), sensitivity 125530 mg(-1) mg l(-1), coefficient variation 0.8-1.6%). Six different varieties of grape skin, from the same geographical area and representative of the wine elaboration, were analysed.     

Antioxidant activity,lipophilicity and extractability of polyphenols from pig skin – development of analytical methods for skin permeation studies

Permeation of polyphenols through the stratum corneum barrier is a precondition for the protective action of polyphenols against oxidative skin damage. Prior to in vitro skin permeation experiments, we developed a method for the quantification of polyphenols in pig skin, including organic solvent extraction and HPLC analysis. Catechine hydrate, epigallocatechin gallate, trans‐resveratrol, quercetin, rutin and protocatechuic acid were chosen for this study as representatives of phenolics with different lipophilicity and molecular weight. The antioxidative activities of polyphenols as well as their octanol–water partition coefficients at different pH values were determined. Extraction of polyphenols from pig skin was optimized by variation of solvent composition, homogenization intensity and time, as well as partial exclusion of oxygen during extraction. The highest recovery rates could be reached by extraction with the methanol–water mixture (90:10, v/v), containing 0.2 g/L l ‐ascorbic acid, after the cryo‐milling for 4 min. Recoveries of 72% for total phenolics, 96% for quercetin and protocatechuic acid, 90% for rutin and 74% for trans‐resveratrol, were achieved. These extraction parameters will be selected for the polyphenol extraction from pig skin for further in vitro drug permeation studies. Copyright © 2013 John Wiley & Sons, Ltd.     

Resveratrol content of some wines obtained from dried Valpolicella grapes: Recioto and Amarone

Resveratrol (rans-3,5,4'-trihydroxystilbene), a phenolic substance present in both grape skin and wines, is a phytoalexin involved in grey mould resistance. A new interest has surfaced in recent years related to the antioxidative actions of resveratrol, which in vivo could be related to the prevention of cardiovascular diseases linked to lipid metabolism, particularly HDL production, while the antifungal activity may be of interest in wine production technology. These aspects have led to the publication of a number of papers reporting data on the resveratrol content of several kind of wine: for Italian wines, it ranges between 0.5 and 10 ppm, depending on cultivar, area of cultivation, climate and wine-making technology. In this work, resveratrol was quantified in samples of two unusual Italian wines, Recioto (sweet) and Amarone (dry), produced with the same cultivar mixture in the same area (Valpolicella, Verona, Italy) and with the same grape conditioning technique. After resveratrol extraction, reversed-phase HPLC analysis was carried out and several elution conditions were tested. The resveratrol content of Recioto and Amarone wines was lower than the values reported in the literature for other wines, ranging between 0.05 and 0.8 ppm.     

葡萄酒中白藜芦醇的固相萃取GC/MS法测定及其生理活性的初步研究

用反向C₁₈固相萃取小柱对葡萄酒进行了预处理,然后用BSTFA硅烷化试剂对萃取物进行了衍生化处理,用气相色谱/质谱对葡萄酒中顺式、反式白藜芦醇进行了同时测定,建立了定量分析方法.对方法的精密度和回收率进行了测定,方法的相对标准偏差分别为4.48%(顺式)和5.23%(反式).顺式、反式白藜芦醇的平均回收率分别为94.4%和97.6%.并对10种国产葡萄酒和两种进口葡萄酒样品进行了测定.对白藜芦醇的生理活性也进行了实验,初步探讨了白藜芦醇对大鼠血管平滑肌细胞(VSMC)、大肠癌细胞株Lovo细胞和小鼠成纤维株3T3细胞的生长生殖活性的影响,观察了其形态变化.     

A novel multicommuted fluorimetric optosensor for determination of resveratrol in beer

Resveratrol (3,5,4′-trihydroxystilbene) is a phytoalexin that plays a central role in the human diet because of its antioxidant, anticarcinogenic and antimutagenic properties. This paper shows the development of a multicommuted optosensing device for the determination of resveratrol in beer. The method is based on the measurement of the fluorescence (277/382 nm, λ_ex/λ_em) of the photoproduct on-line generated by UV-irradiation of resveratrol. The fluorescent photoproduct is monitored once it is retained on a solid support (Sephadex QAE A-25) in the detection area, which improves both sensitivity and selectivity. The sample was delipidated with toluene and cyclohexane and resveratrol was extracted by solid-phase extraction (SPE) on C₁₈ cartridges, using methanol as eluent. This pre-treatment allowed recovering about an 82% resveratrol and removing its 3-O-β-d-glycoside (piceid) and other interfering substances present in beer. The method provides a detection limit (DL) of 1.0 ng mL⁻¹ and a linear dynamic range (LDR) of 3.3-100 ng mL⁻¹. It was satisfactorily applied to the determination of resveratrol in top- and bottom-fermented beers by standard addition calibration. Resveratrol concentrations in the analysed samples varied from 4.1 to 14.1 ng mL⁻¹. This is the first proposed spectroscopic method for determination of resveratrol in beer.     

Determination of resveratrol in wine by photochemically induced second-derivative fluorescence coupled with liquid–liquid extraction

Basic studies on the photochemical behaviour of trans-resveratrol and its photoproduct are reported. Photometrically and fluorimetrically calculated acidity constants of the former were determined. The usefulness of the determination of resveratrol by photochemically induced fluorescence and second-derivative photochemically induced fluorescence was also examined. The very weakly fluorescent trans-resveratrol is converted into a highly fluorescent photoproduct by irradiating hydroethanolic solutions of trans-resveratrol containing 40% v/v of ethanol for 60 s with intense UV radiation. The photoproduct presents excitation and emission maxima centred at 260 nm, and 364 and 382 nm, respectively. Under these conditions, a linear relationship between fluorescence intensity and trans-resveratrol concentration was found between 6.6 and 66 ng mL⁻¹. Optimum conditions for the extraction of trans-resveratrol from an aqueous phase at pH 5.0 with diethylether were a phase ratio (aqueous/organic) of 2, a shaking time of 60 s and a buffer concentration of 0.15 mol L⁻¹. An extraction recovery of 100% was reached under these conditions. The optimized extraction procedure was applied to the analysis of resveratrol in wine samples, employing the amplitude between 356 and 364 nm of the second-derivative photoinduced emission spectrum as analytical signal. It was found that there is not matrix effect and recoveries around 100% were obtained at different fortification levels.