超高效合相色谱(UPC^(2))技术快速测定植物油中的维生素A和维生素E北大核心CSCD

为了使植物油中脂溶性维生素E异构体得到更好的分离,建立一种超高效合相色谱(UPC^(2))快速分离和测定植物油中维生素A和维生素E的方法。样品经异丙醇溶解,过0.22μm有机相滤膜后直接进样分析。分析条件为HSS C_(18)SB色谱柱(3.0 mm×100 mm, 1.8μm),CO_(18)和0.2%甲酸甲醇溶液为流动相,梯度洗脱,流速1.0 mL/min,柱温50℃,检测波长290 nm。结果表明:维生素A和维生素E在测定范围内呈现良好的线性关系,相关系数均在0.999 5及以上,样品回收率为82.00%~106.82%,RSD在0.94%~3.57%之间,日内精密度与日间精密度的RSD分别为1.94%~3.51%与3.74%~5.13%,并采用已建立的方法对26份植物油样品中的维生素A和维生素E含量进行测定,表明植物油中维生素E含量最高,其中以α-生育酚和γ-生育酚为主,β-生育酚含量较低。该方法简单高效、灵敏度高、重复性好,可用于植物油中脂溶性维生素A和维生素E的分离检测。     

国家标准方法在橄榄油α-生育酚含量测定的应用

目的 探究反相高效液相色谱法和正相高效液相色谱法检测橄榄油α－生育酚含量。方法 反相高效液相色谱法采用C30柱, 流动相甲醇/水梯度洗脱,流速为0.8 mL/min, 柱温为20 ℃, 紫外检测波长为 294 nm; 正相高效液相色谱法采用Si120硅胶色谱柱, 流动相为正己烷/1,4二氧六环按(95:5), 流速为 0.8 mL/min, 柱温为30 ℃, 荧光检测激发波长为294 nm, 发射波长为328 nm。结果 反相色谱法测定α-生育酚的线性范围为2.00~60.00 μg/mL, 定量限为0.6 μg/mL, 精密度RSD为5.5, 回收率为90%~105%, RSD为5.5%。正相色谱法测定α-生育酚的线性范围0.200~6.00 μg/mL, 定量限为0.014 μg/mL, 精密度RSD为1.8%, 回收率为99%~103%, RSD为1.2%。结论 正相色谱简便、更快速、更灵敏、更准确, 更适合初榨橄榄油中α-生育酚的定量测定。     

高效液相色谱法同时测定营养强化面包中脂溶性维生素

本试验建立了高效液相色谱法同时测定营养强化面包中3种脂溶性维生素—维生素A(视黄醇)、维生素E(α-生育酚)和维生素D3含量的方法,采用C18色谱柱,流动相为甲醇-水(98:2),检测波长300nm,流速1.6ml/min,各维生素的线性关系良好(R2≥0.9996),回收率88.5%～107.1%(RSD2.36%～4.14%)。本文详细说明标准品的处理和标定方法,结果表明,该方法准确可行。     

高效液相色谱-串联质谱法测定保健食品中的维生素A、D、E

目的建立高效液相色谱-串联质谱法同时测定保健食品中维生素A、D、E的分析方法。方法样品中的维生素在氮气保护下进行皂化反应,经正己烷提取,旋蒸至近干后用流动相定容至一定体积,采用高效液相色谱-串联质谱法选择反应监测(SRM)正离子模式进行测定。结果维生素A、维生素D_2、维生素D_3、α-维生素E、β-维生素E、γ-维生素E和δ-维生素E的线性范围分别为10~1 000、2~100、1~100、25~2 000、5~500、5~500、5~500μg/L,且浓度范围内线性关系良好。方法的相对标准偏差范围为1.3%~5.5%(n=6),保健食品中维生素A、D、E的平均回收率范围为90.4%~105.0%,7种维生素检出限分别为:维生素A 2.0μg/kg、维生素D_2 2.0μg/kg、维生素D_3 0.2μg/kg、α-维生素E 0.2μg/kg、β-维生素E 0.5μg/kg、γ-维生素E 0.5μg/kg、δ-维生素E 1.0μg/kg。结论本法可同时对保健食品中维生素A、D、E进行定性和定量分析,方法的精密度、回收率和检出限能满足实际检测要求,可用于保健食品中维生素A、D、E含量的日常监测。     

正相超高压液相色谱法测定植物油中的维生素E

采用正相超高压液相色谱法测定油脂中4种常见生育酚的含量,确定一种简单、准确、快速测定维生素E的测定方法.样品经前处理后,用Zorbax RX-SIL硅胶柱分离,以乙酸乙酯-异辛烷为流动相梯度洗脱,在波长295nm采用外标法检测α、β、γ、δ等四种生育酚在不同植物油中的含量.研究结果表明,该方法四种异构体均在8min内出峰,线性关系在0.9994～0.9999间,精密度RSD＜5％,加标回收率在80％～100％,线性范围0.2～100.0μg/mL,α、β、γ、δ异构体方法检出限均在0.01μg/g左右;几种典型植物油样品验证实验表明该方法体系具有快速、准确、分离度好等特点.同时比较了调和油和精炼地沟油维生素E含量差异,初步确定α-维生素E可能作为该类地沟油识别因子.     

高效液相色谱法测定芡实中不同构型维生素E的含量

目的:建立了芡实中不同构型维生素E的RP-HPLC含量测定方法。方法:采用高效液相色谱分析,Waters XBridge C18柱(4.6mm×150mm,5μm),以A相甲醇和B相水(97∶3)为流动相等度洗脱,流速为1.0mL/min,柱温:30℃,检测波长为295nm。结果:α-生育酚、β+γ-生育酚、δ-生育酚均能够达到基线分离,α-生育酚在0.12~1.2g/L范围内具有良好的线性关系,R21=0.9998;β+γ-生育酚在0.056~0.56g/L范围内具有良好的线性关系,R22=0.9999;δ-生育酚则在0.0096~0.096g/L范围内具有良好的线性关系,R23=0.9998。平均加样回收率分别为100.47%,100.04%,99.10%;RSD分别为0.27%,4.65%,1.92%。安徽安庆芡实中总VE含量最高,可达2.2633mg/g。结论:该方法简便、准确、重现性好,为芡实药材的质量评价提供合理的参考依据。     

HPLC法测定小麦胚咀嚼片中维生素E

确定了高效液相快速测定小麦胚咀嚼片中维生素E含量的方法。色谱柱为反相C18柱(150mm×4.4mm),流动相为99%甲醇,检测波长为280nm,流速1.0ml/min,线性相关系数为0.999 4,检出限为0.2mg/L,重现性的相对标准偏差(RSD)为0.24%,方法的精密度RSD为1.005%,平均回收率97.8%。     

高效液相色谱法测定食品中维生素K1和维生素K2的含量

建立高效液相色谱-荧光检测法（HPLC-FLD）测定食品中维生素K₁和维生素K₂含量的分析方法。方法:配方奶粉、酸奶、纳豆冻干粉和鸡胗冻干粉经酶解、异丙醇分散、正己烷萃取、旋转蒸发复溶后,使用Thermo AcclaimTM 120 C₁₈色谱柱（150 mm×4.6 mm,5 μm）分离,锌粉还原柱（50 mm×4.6 mm）衍生,以900 mL甲醇:100 mL四氢呋喃（含冰醋酸0.3 mL,氯化锌1.5 g,无水乙酸钠0.5 g）为流动相,激发波长为243 nm,发射波长为430 nm,分离维生素K₁（Vitamin K₁,VK₁）、四烯甲萘醌（menaquinone-4,MK-4）、七烯甲萘醌（menaquinone-7,MK-7）和九烯甲萘醌（menaquinone-9,MK-9）。结果:VK₁、MK-4、MK-7和MK-9在20~1000 μg/L范围内与峰面积有良好线性关系。配方奶粉、酸奶、纳豆冻干粉和鸡胗冻干粉中VK₁、MK-4、MK-7、MK-9含量的相对标准偏差（RSD）均小于5%,表明精密度好。配方奶粉、酸奶和纳豆冻干粉不同水平加标回收率分别为85.0%~107.8%、85.8%~109.6%、85.1%~102.7%,回收率的RSD均小于5%,表明回收率高,相对标准偏差小。结论:实验建立的方法重复性好、准确度高,可以精准定量食品中维生素K₁和维生素K₂的含量。     

手性液相色谱法直接定量乳粉中RRR-α-生育酚

目的 建立一种乳粉中RRR-α-生育酚的手性液相色谱直接检测方法。方法 样品经氢氧化钾皂化, 石油醚-异丙醚萃取。经小粒径纤维素衍生物型手性柱Daicel Chiralcel OD-3 (2.1 mm×150 mm, 3 μm)直接分离,采用无水乙醇-正己烷(5: 995, V/V) (A)和三乙胺-正己烷(5: 995, V/V) (B) (A:B=10:90)作为流动相进行等度洗脱, 流速为0.2 mL/min, 柱温30 ℃, 检测波长为294 nm, 外标法定量。结果 RRR-α-生育酚和其他α-生育酚异构体的分离度大于1.2。在0.5~50 μg/mL 范围内线性关系良好, 相关系数大于0.999, 检出限为0.20 mg/100 g , 定量限为0.60 mg/100 g, 加标回收率为95%~109%, 相对标准偏差为2.7%。结论 该方法快速、准确、灵敏, 适合测定乳粉中RRR-α-生育酚的含量。     

高效液相色谱法测定强化食品中维生素B6的含量

目的 建立了一种高效液相色谱法检测强化食品(婴幼儿配方食品、婴幼儿谷类辅助食品和功能饮料)中维生素B6方法。方法 利用Eclipse Plus C18(5 μm, 4.6 mm×250 mm)色谱柱, 流速1 mL/min, 流动相: 甲醇-(0.2 g/L辛烷磺酸钠, 体积分数为0.25%的三乙胺溶液, 利用乙酸调节pH=3.2±0.1)(V:V=21:79), 进样量 10 μL, 柱温30 ℃实现了对吡哆醛、吡哆醇和吡哆胺3种组分的分离; 在激发波长293 nm, 发射波长395 nm的条件下实现了对这3种组分的检测。结果 吡哆醛、吡哆醇和吡哆胺在0.1~1.0 μg/mL范围内均表现出良好的线性关系, 3种组分的相关系数均大于0.999, 检出限为0.01~0.02 mg/100 g, 定量限为0.03~0.05 mg/100 g, 均满足现行国标要求。3种维生素B6在添加水平为0.05、0.20和0.60 mg/100 g时的加标回收率为89.6%~107.1%, 相对标准偏差(n=6)为1.3%~7.0%。结论 该方法操作简便, 准确度和精密度高, 能够用于对多种常见强化食品中3种维生素B6的检测     

脂溶性维生素对多种慢性疾病治疗作用的研究进展

综述脂溶性维生素抗炎、抗氧化等生物活性对糖尿病、骨质疏松、慢性肾脏病等慢性疾病治疗作用的研究进展。     

Physicochemical effect of pH and antioxidants on mono- and triglutamate forms of 5-methyltetrahydrofolate,and evaluation of vitamin stability in human gastric juice: Implications for folate bioavailability

This report examines the physico-chemical properties of mono and triglutamate forms of 5-methyltetrahydrofolate_n (5CH₃–H₄–PteGlu_n) in human gastric juice and under artificial conditions, typical of the upper gastrointestinal tract.     

The stability of pyridoxine hydrochloride used as a fortificant in Asian wheat flour noodles

The impact of ingredients, pH and cooking on fortification of Asian noodles with vitamin B6 has been investigated. Fortification for three styles of noodle, using pyridoxine hydrochloride, resulted in enhanced levels in the final cooked products. For each, the overall retentions were similar and the varying formulations and processes for each style had relatively little impact on stability of the fortificant. Losses occurred at most stages during processing, including the initial mixing of the doughs. Product pH was not a primary determinant, and the greatest losses were found for steps involving elevated temperatures, particularly deep-frying of instant noodles, as well as boiling of the each of the three styles. Allowance for the total losses of 57–66% would require the incorporation of substantial overages during formulation of Asian noodles.     

Determination of vitamins A and E in cooked sausages

A reliable and sensitive reverse-phase HPLC method is described for the separation and quantification of all-trans-retinol and dl-α-tocopherol in cooked sausages. Samples were chromatographed with UV and fluorescence detection on a 15 cm × 0.4 cm i.d. Spherisorb ODS-2, 5 μm column, using as mobile phase a mixture of 90% acetonitrile and 10% tetrahydrofuran. Sample preparation included saponification and extraction by n-hexane. Addition of pyrogallol and oxygen-free conditions avoided oxidation of both vitamins, increasing recovery percentages, which ranged from 90.0 to 95.0%. Precision was 1.0% (within a day) and 3.4% (between days) for all-trans-retinol and 1.1% (within a day) and 2.6% (between days) for dl-α-tocopherol. Detection limits were 10 μg/100 g for all-trans-retinol and 0.1 mg/100 g for dl-α-tocopherol with a signal-to-noise ratio of 3. Twenty samples of six different products were analyzed in duplicate. Average for all-trans-retinol in “enriched chopped” was 108 mg/100 g fresh weight, and the mean value for dl-α-tocopherol in “enriched chopped” was 2.3 mg/100 g fresh weight.     

不同贮存条件下生菜中维生素C和E含量分析

采用高效液相色谱法对在5个时间梯度处理、2个温度梯度处理条件下生菜叶片中维生素C和E含量进行了分析。结果表明,维生素C对贮存时间和温度特别敏感。低温或室温贮存1d的生菜中维生素C含量均损失50%以上,而维生素E含量包括α-生育酚含量反而有所提高;但低温或室温贮存3d后生菜中维生素C含量和维生素E含量特别是α-生育酚含量均急剧下降。因此,从营养利用的角度考虑,生菜的贮存以低温1～3d为宜,室温和长时间贮存会造成维生素C和E的大量损失。     

Dietary antioxidants in the prevention of hepatocarcinogenesis: A review

In this review, the role of dietary antioxidants in the prevention of hepatocarcinogenesis is examined. Both human and animal models are discussed. Vitamin C, vitamin E, and selenium are antioxidants that are essential in the human diet. A number of non‐essential chemicals also contain antioxidant activity and are consumed in the human diet, mainly as plants or as supplements, including β‐carotene, ellagic acid, curcumin, lycopene, coenzyme Q₁₀, epigallocatechin gallate, N‐acetyl cysteine, and resveratrol. Although some human and animal studies show protection against carcinogenesis with the consumption of higher amounts of antioxidants, many studies show no effect or an enhancement of carcinogenesis. Because of the conflicting results from these studies, it is difficult to make dietary recommendations as to whether consuming higher amounts of specific antioxidants will decrease the risk of developing hepatocellular carcinoma.     

高效液相色谱法测定乳粉中维生素A,D

研究了高效液相色谱法,同时测定牛乳中维生素A,D。乳粉样品通过皂化、萃取,提取液通过aminocyano色谱柱净化、silica色谱柱分离,紫外检测器,外标定量法,同时测定出样品中维生素A,D。本法最低检出限VA为1.1×10-8g,VD为2.5×10-8g;变异系数VA为1.917%,VD为5.518%;平均回收率VA为96.3%,VD为90.2%。     

Changes in content of vitamins A and E in growing‐up milk throughout its shelf life

The stabilities of vitamins A and E were determined in 51 samples of growing‐up milk stored at 23, 30 and 37 °C for up to 9 months. Initially, the content of vitamin A and vitamin E was 330 RE μg/100 mL and 1.78 α‐TE mg/100 mL, respectively. Decreases in vitamin content were higher (P < 0.05) in formulas stored at 37 °C (from 330 to 111 μg RE/100 mL for vitamin A and from 1.78 to 1.16 mg α‐TE/100 mL for vitamin E). Over‐fortification of growing‐up milk could be recommended for vitamin E.     

天然维生素E乙酸酯的制备

VE的乙酸酯有比VE更强的化学稳定性及更多药用价值。本文介绍了用天然VE酯化制备VE乙酸酯的试验结果。优化后得到优化的工艺条件为(原料50克)：乙酸酐用量为9．0ml、反应时间为5．5小时、催化剂(三乙胺)用量为5．0ml、反应温度为60℃。VE酯化率为94.93％。