HPLC同时测定保健食品中维生素A、D3、E和β-胡萝卜素

建立了一种同时测定保健食品中维生素A、D3、E、β-胡萝卜素的高效液相色谱法。样品皂化后乙醚提取,旋转蒸干,流动相溶解,HPLC紫外检测。实验结果显示,VA、VD3、VE和β-胡萝卜素的线性范围分别为0.012~500、0.030~500、0.12~500和0.015~500μg/mL,且浓度范围内线性良好;检出限分别为0.24、0.60、2.40和0.30μg/g;相对标准偏差分别为1.9%、3.4%、4.6%和2.9%;VA、VD、VE和β-胡萝卜素的加标回收率为84.8%~119.0%。分析周期在20 min以内,方法适合保健食品样品的分析。     

高效液相色谱法同时测定食品中脂溶性维生素A,D3,E,K3

１引言维生素是维持细胞正常生理功能的营养成分之一。许多维生素是酶的辅基或酶的组成成分，因此，测定食品中维生素的含量是食品营养分析的主要内容之一。脂溶性维生素的分析方法一般采用生物法、分光光度法及薄层色谱法等，但这些方法都只能单独测定食品中的维生素，进入８０年代后，随着高效液相色谱（ＨＰＬＣ）技术在食品分析中的应用，国外许多研究工作者在利用高效液相色谱技术分析脂溶性维生素的研究上作了许多工作，发展了更具选择性的方法如电化学法、质谱法等，并且对同时测定脂溶性维生素的方法作了一些探索。本文旨在综合国内…     

高效液相色谱法同时测定无骨海鱼中的维生素A、D和E

采用反相高效液相色谱法,以甲醇(49 1)为流动相,对维生素A、D和E混标进行高速紫外扫描,在Nova Pak C18柱上获得分离良好的三维图谱。据此,选择维生素A、D和E各自最大吸收波长325、265和290nm作为检测波长。实验结果表明:无骨海鱼中维生素A、D和E的质量分数分别为0.80、0.17、4.14mg kg,相对标准偏差为3.7%～5.0%。质量浓度0.10～10mg L范围内,维生素A、D、E均呈现良好的线性关系,检出限为0.05～0.62mg L,回收率在90.0%～110%之间。     

高效液相色谱法测定人血清中维生素A、E、C的含量

分别建立了同时测定人血清中维生素A和维生素E的以及测定维生素C的高效液相色谱方法。维生素A、E血清样品用正己烷提取,ODS色谱柱分离,流动相为甲醇,检测波长为325nm、292nm。维生素C血清样品用维生素C提取溶剂提取,ODS色谱柱分离,流动相为甲醇-30mmol/LKH2PO4缓冲液,检测波长为234nm。维生素A、维生素E、维生素C线性范围分别为89.1～1425.0μg/L、4.6～73.9mg/L、0.5～15.0mg/L,相关系数r均大于0.9996。维生素A、E、C高、中、低3个浓度的平均回收率为84.0%～101.2%,相对标准偏差为0.9%～5.1%。该方法准确可靠,可用于测定人血清样品中的维生素含量。     

高效液相色谱法同时测定秋葵干蔬中的脂溶性维生素A、E、K3

建立了同时测定秋葵干蔬中脂溶性维生素A、E、K3的反相高效液相色谱法.样品皂化后,采用C18色谱柱(150 mm×4.6 mm,5μm i.d.)进行分离,以甲醇为流动相,流速1.0 mL/min,二极管阵列检测器(DAD)在325、290、244 nm波长下同时检测,外标法定量.结果表明,脂溶性维生素A、E、K3在0...     

液相色谱电化学安培检测乳粉中的脂溶性维生素A, E和D3

利用维生素A、D3、E均有电化学活性的特点,采用电化学安培检测,建立了HPLC检测奶粉中的脂溶性维生素A、D3、E的新方法.流动相为甲醇∶水=95∶5(V/V),含0.05 mol/L高氯酸钠.检测器采用玻碳电极,直流安培模式(DC),氧化电位 1.3 V.方法检测限为:VA、VD3、-αVE、-γVE、-δVE分别为0.08、2.3、0.16、0.19、0.28ng.回收率分别为:90.2%~98.2%、91.2%~103%、92.7%~99.5%、92.6%~97.4%、90.7%~98.0%.同紫外检测比较,方法具有灵敏度高、抗干扰强的特点.     

在线二维反相色谱法快速测定维生素AD制剂中维生素A、D的含量

建立了在线二维液相色谱法快速同时测定维生素AD制剂中维生素A和D的含量。依据药典对系统适应性的要求,选择一种极性嵌合的C_(18)柱(Accucore polar premium)作为二维色谱柱,再依据疏水减法模型原理和待测样品的脂溶性特点,选择C_8柱作为一维色谱柱,一维和二维分离均采用甲醇、乙腈和水作为流动相。样品经乙醇提取后直接进样分析,采用双梯度液相色谱右泵作为一维分析泵,完成含量较高的维生素A定量及维生素D的净化;采用左泵作为二维分析泵,维生素D及前维生素D在二维色谱柱上实现分离和定量。根据维生素D在一维色谱上的出峰起止时间,确定切割时间窗口,以500μL定量环收集含有目标物的馏分,检测波长分别为264 nm和325 nm。采用外标法完成对维生素D和前维生素D的定量。整个过程在密闭系统中自动化完成。维生素A在0.1~250 mg/L,维生素D在0.02~50.0 mg/L范围内线性关系较好,相关系数(r)大于0.999;维生素D的回收率为89.9%~98.9%,连续进样的精密度和重现性的RSD分别为0.48%和1.2%,表明方法的精密度和重现性较好。     

超临界色谱法同时测定化妆品中维生素A类衍生物和维生素D2,D3

采用超临界色谱法建立了同时测定化妆品中维生素A乙酸酯、维生素A丙酸酯、维生素A棕榈酸酯、维生素D2和D3的分析方法。水溶性化妆品和油溶性化妆品经不同比例的水-乙腈-正己烷溶剂体系按不同的添加顺序进行分散、提取后,采用Viridis BEH 2-EP色谱柱(250×4.6 mm,5μm),以CO2为流动相,异丙醇-正己烷(1∶1)为改性剂,进行梯度洗脱分离,光电二极管矩阵检测器(SFC-PDA)检测,结合保留时间和光谱图定性,外标标准曲线法定量。实验结果表明,5种目标物质量浓度在1.0~60 mg/L范围内线性关系良好,相关系数为0.9992~0.9996;维生素A乙酸酯、维生素A丙酸酯、维生素A棕榈酸酯的定量下限(S/N=10)为4.0 mg/kg,维生素D2和D3的定量下限(S/N=10)为8.0 mg/kg。空白基质加标回收率为93.8%~110.1%,相对标准偏差(RSDs)小于13%。方法适用于各类化妆品中维生素A乙酸酯、维生素A丙酸酯、维生素A棕榈酸酯、维生素D2和D3的测定。     

Separation and Assay of Cholecalciferol in Vitamin A + D Ointment

Summary. In this paper two methods are presented. One involves the separation of cholecalciferol from a topical ointment. The other involves the assay of cholecalciferol in this ointment. The study was performed with normal-phase high performance liquid chromatography using a NP-L3 column and UV detection. Applying a mobile phase mixture containing n-hexane:2-propanol (99:1) a total separation was achieved within 15 min. For isolation and assay of cholecalciferol from an ointment (vitamin A + D), dissolution in n-hexane gave the highest recovery (>95%). The isolation and assay process can be performed within 3.5 h.     

饲料和鱼肝油丸中维生素A的分光光度测定

本文介绍了饲料和鱼肝油丸中维生素A经脱水处理后的分光光度测定法。维生素A在对甲苯磺酸的作用下脱水,其最大吸收波长从326.5 nm红移到397 nm;当维生素A浓度在0～9μg/mL时,397 nm处的吸光度正比于维生素A的浓度。本法灵敏度高,精密度好,线性范围宽,相关系数为0.999,不受共存的维生素E和D及其它杂质的干扰,操作简单。均匀样品的回收率为96.5～107.3%,变异系数为1.96～3.09%,适于复杂混合物中维生素A的测定。     

A CIDEP and fluorescence study of the oxidation of vitamin E: The vitamin E radical cation

The photochemical and thermal oxidations of vitamin E in trifluoroacetic acid were investigated by the combination of electron spin resonance, chemically induced dynamic electron polarization, and fluorescence techniques. Two independent thermal pathways led to the formation of the vitamin E radical cation in which one of the paths involved the intermediate neutral semiquinone radical. Photo-oxidation, however, did not involve the neutral radicals. The fluorescence spectra of both the neutral and the charged forms of the vitamin E radicals are reported here for the first time. Some model charge transfer reactions involving the vitamin E radical cation were reported.     

Comparison of Extraction Methods by Soxhlet, Sonicator, and Microwave in the Screening of Pesticide Residues from Solid Matrices

Three types of solvent extraction methods (by soxhlet, sonicator and microwave) for pesticide recoveries in solid matrices were compared and evaluated using the standard addition method. Variables (solvent and extraction time) for the optimization of microwave assisted extraction (MAE) were also studied. Three organochlorine pesticides (BHC, DDE, and Dildrin) were chosen for this particular study because of their great presence in the soil where the samples were collected and their positive association with the risk of breast cancer. Comparison of the results obtained indicates that the efficiency of extraction varies, depending on the matrices and the pesticides analyzed. The study focused on the variation in the extraction quantities of different methods in different matrices. The extraction conditions were optimized for MAE with a single matrix (bark) and applied to the rest in order to study the variability in results. Gas chromatography with an electron capture detector (GC–ECD) was used for analysis of the extracts. The results show that even though the use of MAE improved extraction in some of the matrices studied, the extraction method must be optimized whenever a new matrix is evaluated. A statistical comparison indicated that pesticide recoveries and method reproducibility of microwave extraction compared less favorably with the conventional soxhlet method in some of the matrices, whereas the sonicator method was not found to be as efficient as the others.     

Determination of Vitamins A and E Exploiting Cloud Point Extraction and Micellar Liquid Chromatography

Cloud point extraction and micellar chromatographic methods were developed for determination of vitamins A and E. The stationary phase was C18 and the mobile phase was 3.00% (w/v) SDS, 15.0% (v/v) butyl alcohol and 0.02 mol L^?1 phosphate buffer solution at pH 7.0. The retention times for vitamins A and E were 9.6 and 13.0, respectively. The extraction solution was 100 mmol L^?1 Triton X-100, 650 mg NaCl and 1.0% ascorbic acid at 70°C for 30 min. The method is precise (r.s.d. < 7%), the linear range was from 5.0 up to 360.0 mg L^?1 for both vitamins. Recovery test showed recuperation between 90.2 and 99.2%, and LOD and LOQ of 0.234 and 0.108 mg L^?1, 0.780 and 0.360 mg L^?1 to vitamins A and E were found.     

粤东7种野菜中硝酸盐、亚硝酸盐及维生素C的测定

测定了粤东产7种野菜中的硝酸盐、亚硝酸盐和维生素C.参考蔬菜中硝酸盐分级评价标准,和我国制定的无公害蔬菜亚硝酸盐限量标准,考虑到各种野菜的维生素C的量,对这7种野菜评价如下：积雪草、天胡荽、南方菟丝子和假的硝酸盐量低于轻度污染水平,亚硝酸盐量低于我国制定的无公害蔬菜亚硝酸盐的限量标准（4.0 mg/kg）,维生素C的含量高或较高,所以,它们属于一级野菜, 可以安全食用;蛇含委陵菜和苍耳由于亚硝酸盐量过高,不宜食用或限量食用;荷莲豆的硝酸盐量高于1440 mg/kg,属于高度污染水平,亚硝酸盐量超过我国制定的无公害蔬菜亚硝酸盐的限量标准,不宜食用或限量食用.     

紫花野菊、小红菊与野菊花挥发油化学成分的比较研究

报道了用毛细管气相色谱和色－质谱联用方法分离鉴定紫花野菊和小红菊的挥发油化学成分。初步鉴定了以反－丁香烯,β－蒎烯,１,８－桉叶素等为主的二十八种成分,并测定了它们的含量。同时与野菊花进行了比较。结果表明两者与野菊花主要成分有所不同。     

Simultaneous assay of serum vitamin A and vitamin E by high performance liquid chromatography using time-switched UV and fluorimetric detectors

An HPLC method utilizing a UV and a fluorimetric detector linked in series is described. By use of a simple integrator-controlled time-switched relay, analysis of serum vitamin A and E is accomplished on the same chromatogram and at optimum sensitivity for each detector. A single internal standard (retinyl acetate) monitored only by the UV detector permits measurement of both vitamins over a wide linear range. Precision of the assays is satisfactory, both on a within-day and on a day-to-day basis. Recoveries of both vitamins are virtually 100% whilst sensitivity is 2 μg/L (retinol) and 0.05 mg/L (α-tocopherol).