紫杉醇的薄层层析显色反应与应用

为了进行抗癌药物紫杉醇产生菌株的快速筛选,建立了紫杉醇检测的薄层层析(TLC)方法。研究结果表明,应用薄层层析技术对内生真菌的发酵产物进行检测比高效液相色谱(HPLC)方法更加高效,能够简便、准确的筛选到紫杉醇产生菌株,并且可以初步推测菌株的紫杉醇产生能力。     

Suitability of thin layer models for infrared-hot air-drying of onion slices

Onion slices were dried under different processing conditions applying infrared radiation assisted by hot air. Drying temperature, slice thickness, inlet air temperature and air velocity were varied to study the drying behavior. Thin layer models such as Page, modified Page, Fick's and Exponential models, which are used to describe the drying kinetics of food materials, were tested for the combination mode drying. The linear plots for Page and modified Page models gave a better fit (R²=0.980-0.995) over the other two models (R²=0.767-0.933). A combined regression equation developed to predict the drying parameters (k and n) for all the four models gave a fairly good fit (R²=0.852-0.989). The modified Page model gave better predictions for drying characteristics over the other models.     

薄层扫描法测定罗汉果糖苷(V)含量的研究

建立采用薄层扫描法测定罗汉果糖苷(V)含量的方法。点样于硅胶G板上,以正丁醇-乙醇-水(8∶2∶3)为展开剂,10 %硫酸乙醇显色,单波长反射法锯齿扫描,λ=5 0 0 nm。罗汉果糖苷(V)在2 .0～16 . 0 μg范围内具有良好的线性关系,r=0 .992 1,平均回收率为97.6 2 % ,RSD为2 .5 9% (n=4 )。该法简便快速、准确灵敏,可用于罗汉果糖苷生产质量监控。     

An improved high performance liquid chromatographic method for thiamin analysis in foods

A high performance liquid chromatography (HPLC) procedure for the determination of thiamin in foods has been developed. Acid and enzymatic extracts of food samples were subjected to purification and chromatographic conditions which allowed the quantification of thiamin in foods with only a low content. Reverse-phase ion pair chromatography, using mixtures of sodium hexanesulfonate and sodium heptanesulfonate as counterions and detection at 254 nm, was employed. The lowest detection limit for thiamin was 0.5 ng/injection. Analyses of four samples of legumes and lyophilized meat and milk and the recovery for standard thiamin are given. Mean recovery values of extraction and purification procedure ranged over 97-98%.     

皂苷不同测定方法的比较

皂苷化合物是一类分布广泛、具有重要药理活性的天然化合物,其结构复杂、种类繁多,测定其在植物、药物制剂和保健食品中的含量十分重要。本文对植物皂苷的测定方法进行了概括,以利于今后皂苷成分的分析、测定工作。     

三种色谱法分析鲍鱼生殖腺多糖的单糖组成

为了选择一种准确有效的方法测定鲍鱼生殖腺多糖(AGP-32)的单糖组成。采用薄层色谱法、气相色谱法和高效液相色谱法对AGP-32的单糖组成进行测定。结果表明:高效液相色谱法较其它色谱方法具有分离效果好,并可同时检测中性糖、糖醛酸和氨基糖等特点,并利用该法得到单糖组成的摩尔比为Man∶Rha∶GlcA∶GalA∶Glc∶Gal∶Xyl∶Fuc=0.79∶2.05∶1.6∶0.58∶0.09∶4.91∶0.11∶0.34。说明高效液相色谱法较其它色谱法更加适合于鲍鱼生殖腺多糖这类复杂样品的单糖组成分析。     

Modeling of baking of thin layer of cake using the lumped reaction engineering approach (L-REA)

Baking is a simultaneous heat and mass transfer process commonly applied in the food industry. It is desirable to have a simple, accurate and robust model in order to assist efficient process design and evaluation of product quality. The reaction engineering approach which was proven to be accurate to model several challenging drying cases, was implemented in this study to model the baking of thin layer of cake. The equilibrium activation energy (ΔE_v,b) was evaluated according to the baking oven temperature and corresponding humidity. It was then combined with the relative activation energy (ΔE_v/ΔE_v,b) to produce a unique relationship. Results of the modeling indicate that the L-REA can describe the profiles of moisture content and temperature very well. While the results are accurate, the model itself remains simple. Another significant application of the REA for modeling the processing of food products has been made by this research.     

Simple,rapid and valid thin layer chromatographic method for determining biogenic amines in foods

A simple, rapid and valid thin layer chromatographic (TLC) method for determining biogenic amines in foods is established. Biogenic amines were extracted from foods with 5% TCA, the extract was washed by ethyl ether, the washed extract was dried and the dansyl derivatives were prepared. Separation of the dansylated amines was achieved on silica gel TLC plates by multiple development technique, and quantification was performed by densitometry at 254 nm. The response of the densitometer was linear and highly correlated with the amounts of dansylamines. The calculated determination coefficient (r²) ranged from 0.997 to 0.970. The sensitivity of the method was 45, 174, 703, 101, 132, 88, 515 and 61 for TRY, PUT, CAD, SPD, HIS, SPM, TYR and PHE, respectively. The relative standard deviation (RSD) of the proposed method (repeatability) ranged from 0.39 to 6.36% for TYR (80 ng) and PHE (20 ng), respectively. The accuracy of the proposed method ranged from 86.2 to 93.2% for PHE and HIS, respectively, and there was no significant differences (p<0.05) between the recoveries obtained for all kinds of food analyzed. The limit of detection of the proposed method was found to be 10ng for TRY, SPM and PHE, and 5 ng for the other biogenic amines tested. ©     

High-performance thin layer chromatographic method for quantitative determination of curcuminoids in Curcuma longa germplasm

Phytochemical investigation of the rhizomes of Curcuma longa leads to the isolation of pharmacologically active curcuminoids viz Curcumin, demethoxycurcumin and bisdemethoxycurcumin. These were isolated from turmeric rhizomes by soxhlet extraction followed by column chromatography, crystallisation and identified by spectroscopic studies. The purity of the curcuminoids was analysed by HPTLC method. The method employed TLC aluminium plates precoated with silica gel 60GF₂₅₄ as the stationary phase. The solvent system consisted of chloroform: methanol (48:2, v/v). This system was found to give compact spots for curcumin, demethoxycurcumin and bisdemethoxycurcumin (R_F value of 0.66 ± 0.02, 0.48 ± 0.02 and 0.30 ± 0.02), respectively. Densitometric analysis of curcuminoids was carried out in the absorption–reflection detection mode at 425 nm. Seven different germplasm of turmeric were analysed to detect the percentage of these three curcuminoids.     

A reliable,simple and cost-efficient TLC-HPLC method for simultaneously determining florfenicol and florfenicol amine in porcine urine: application to residue surveillance

ABSTRACT

Violative residues of florfenicol (FF) in porcine edible tissues pose a potential risk for human health. In this study, urine was selected as target matrix for routine residue monitoring of FF in pig, and a thin layer chromatography (TLC)-high-performance liquid chromatography (HPLC) method was developed for simultaneously determining FF and florfenicol amine (FFA) in porcine urine. The urine samples were extracted with ethyl acetate under alkaline environment. The extracts were enriched through evaporation, purified by TLC and analysed by HPLC at 225 nm. A Waters Symmetry C₁₈ column was used for the separation of the two analytes. The mobile phase was acetonitrile-phosphate buffer mixtures (33.3: 66.7, v/v), and was pumped at 0.6 mL/min. The TLC-HPLC method was well validated and successfully applied to residue depletion study. Good analytical specificity was confirmed by the lack of interfering peaks at the retention times of FF and FFA. The standard curves showed good linearity (FF: y = 143064x – 1045.3, r= 0.9999; FFA: y = 275826x + 1888.8, r= 0.9999) over the range of 0.0625–8 μg/mL. The precision ranged from 0.83% to 11.66% and 2.19% to 8.75% for intraday and interday determination, respectively. The corresponding accuracy ranged from ?13.38% to 10.78% and ?12.15% to 7.14%, respectively. The limits of quantification (LOQs) for FF and FFA were 0.125 μg/mL. The residue depletion study showed that the concentrations of FF and FFA in urine were higher than those in edible tissues at three time points. This method was reliable, simple and cost efficient, and could be used to monitor FF residues in porcine edible tissue without slaughtering animals. TLC showed excellent purification efficiency and is expected to solve matrix interferences in veterinary drug residue analysis.     

薄层色谱-表面增强拉曼光谱法快速检测改善睡眠类保健食品的主要成分及其光谱表征

目的建立薄层色谱(TLC)与表面增强拉曼光谱(SERS)联用技术对改善睡眠类保健食品的主要成分(褪黑素、维生素B_6)的快速检测新方法。方法以环己烷-乙酸乙酯-乙醇(5∶3.5∶2,V/V)为展开剂,利用TLC将改善睡眠类保健食品中主要成分与保健食品基质初步分离,在UV_(254nm)下检测定位;以780 nm激光为激发波长,水相银胶溶液为表面增强剂,采用SERS法对TLC上的微量成分进行原位定性检测。通过模拟阳性样品试验,考察保健食品基质对褪黑素、维生素B_6的TLC-SERS的影响,并考察褪黑素及维生素B_6的检出限,并随机对市售4种改善睡眠类保健食品进行检测。结果褪黑素、维生素B_6的TLC-SERS与相应对照品的拉曼光谱特征峰存在明显相关性;保健食品的基质对褪黑素和维生素B_6的检测不存在干扰;褪黑素和维生素B_6的检出限为10、5μg。市售改善睡眠类保健食品主要成分的TLC-SERS与褪黑素或维生素B_6基本相同。结论本法准确、灵敏、快速、简单,为检测混合样品等复杂体系主要成分的定性鉴别检测提供一种有效方法。     

Determination of docosahexaenoic acid in milk using affinity solid-phase purification with argentous ions and modified thin layer chromatography

This paper reports a simple method for docosahexaenoic acid determination in bovine milk. The method consists of three steps: (1) one-step DHA methylation in bovine milk without lipid extraction, (2) concentration of DHA methyl ester by AgNO₃-modified silica gel column chromatography, and (3) detection of DHA methyl ester using spot focused-high performance thin layer chromatography. DHA was directly methylated in bovine milk and selectively concentrated in accordance with its intrinsic affinity to argentous ions. Purified DHA methyl ester was developed on newly designed thin layer chromatographic plates with focusing slits and determined densitometrically using conventional software, following visualisation with iodine staining. In addition to the densitometrical analysis, it is also possible for practical, semiquantitative DHA determination to be visually performed on site in manufacturing industries. Unlike conventional methods, the method described needs neither lipid extraction procedures that use a large amount of organic solvent, nor a gas chromatograph system.     

油菜籽薄层真空干燥技术的研究

油菜籽含有丰富的脂肪、蛋白质和多种维生素,是我国主要的油料作物,同时也是蛋白质作物、饲料作物、能源作物和蜜源作物,综合利用效益高.目前我国油菜籽的产地集中在长江中下游地区,收获季节适逢南方的阴雨潮湿天气,使得油菜籽的干燥和储藏成为加工链中亟须解决的问题.主要研究油菜籽薄层真空干燥技术,为新设备的研制开发及加工链提供必要的数据参考.     

Development and application of a high-performance liquid chromatographic method for the analysis of phytoestrogens

A high-performance liquid chromatographic technique was developed for the separation and quantification of isoflavones and coumestans possessing known oestrogenic activity. This has been applied to an examination of samples from the British Total Diet Study and four commercially available soya-based foods.     

Gas chromatographic method for the determination of volatile amines in seafoods

A method of quantitative analysis of trimethylamine (TMA) and dimethylamine (DMA) in seafoods by gas chromatography (GC) was developed. The amines are separated by using a precolumn of Chromosorb 103 with a main column of Carbopack coated with Carbowax 20M and KOH: a flame ionization detector (FID) and a nitrogen-phosphorous-specific flame ionization detector (NPFID) were used. The effectiveness of the procedure was demonstrated on selected seafood samples.     

钛胶反相高效液相色谱法测定饮料中的柠檬酸

建立了钛胶反相高效液相色谱法测定饮料中酸味剂柠檬酸含量的快速检测方法.色谱条件:分离柱为Titania Sachtopore-RP柱(250mm×4.6mm,5μm),流动相为水∶甲醇=60∶40 (v/v)、流动相中含磷酸盐3mmol/L,流速0.SmL/min,柱温60℃,检测波长210nm.线性范围为0.02mg/mL～8.0mg/mL,检出限2.4μg/mL (3σ),回收率为92.79％～99.30％,RSD (n=8) ＜0.72％.准确度和精密度均可满足饮料中柠檬酸的测定要求.     

榅桲委陵菜酸、熊果酸和齐墩果酸等三萜酸类薄层色谱分离鉴别

目的建立榅桲果实和种子中委陵菜酸、熊果酸和齐墩果酸等三萜酸薄层色谱分离鉴定方法。方法以甲醇为溶剂,超声提取榅桲果实和种子,对展开系统、点样量、薄层板、显色剂等薄层色谱条件进行考察,确定最佳薄层鉴定条件。结果以点样量为4μL,将点于高效硅胶GF254板上的样品点浸入1%碘二氯甲烷溶液中预处理,以甲苯:乙酸乙酯:冰醋酸(体积比:14:4:0.5)为展开剂, 10%硫酸乙醇溶液来显色,在366 nm下观察,委陵菜酸、熊果酸和齐墩果酸被同时检识,分离效果好。结论薄层色谱法分辨率高、操作简便、结果可靠,可用于榅桲属中三萜酸类化合物的分离和鉴别。     

食品中米酵菌酸测定方法研究进展

近年来因食品被米酵菌酸污染而导致中毒事件时有发生,本文对食品中米酵菌酸的测定方法进行综合性总结。从最初的薄层色谱法和分光光度法,发展到到高效液相色谱法、高效液相色谱串联质谱法,到最新的超高效液相色谱-四极杆/静电场轨道阱高分辨质谱法进行综述,为以后的米酵菌酸测定方法的开发提供参考。     

An improved LC-MS/MS method for the quantitation of acrylamide in processed foods

An improved liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the determination of acrylamide in processed foods. The homogenized samples, spiked with ¹³C₃-acrylamide as an internal standard, were extracted with water and centrifuged. D₅-3-chloropropanediol as a recovery standard was added to 1-ml aliquots, and the sample was purified with a C₁₈-cartridge column. The extract was directly analyzed using LC-MS/MS without derivatization. The ion transitions of 72–55 m/z (acrylamide), 75–58 m/z (¹³C₃-acrylamide), and 116–98 m/z (d₅-3-chloropropanediol) were found to be the most reliable for the identification and quantification of acrylamide in multiple reaction monitoring. The limit of quantification for acrylamide, defined as a signal-to-noise ratio of 10:1, was 2 μg/kg. The use of d₅-3-chloropropanediol minimized the effects of variation in the sample matrixes and increased the quality of analysis. This method could be applied to the quantification of acrylamide in processed foods.