Direct determination of tocopherols in paprika and paprika oleoresin by liquid chromatography

A method for the determination of tocopherols and tocopherol esters, quantified as tocopherol acetate, in paprika and paprika oleoresin is reported. Paprika samples were extracted with ethyl acetate and aliquots of the extracts were directly injected into a liquid chromatograph. Reverse phase high-performance liquid chromatography with spectrophotometric detection at 280 nm was used. Gradient elution was applied, allowing the determination of tocopherols and tocopherol esters in the presence of carotenoids. The method does not need previous separation steps, so is useful for the routine determination of vitamin E in commercial samples.     

An ultra-high-performance liquid chromatography-tandem mass spectrometry method for simultaneous determination of aflatoxins B1, B2, G1, G2, M1 and M2 in traditional Chinese medicines

An ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method for simultaneous determination of aflatoxins B1, B2, G1, G2, M1 and M2 in traditional Chinese medicines (TCMs) was developed. The approach was characterized in details and a special focus was placed on the recovery rates of isolation procedure in different TCM matrices, i.e. rhizomes and roots, seeds, flowers, grasses and leaves. For this purpose, [¹³C₁₇]-aflatoxinB1 was employed as the internal standard and a reliable solid phase extraction-based clean-up method was developed. The observed recovery rates of the six aflatoxins ranged from 85.6% to 117.6% in different matrices. Then, the established method was successfully applied to the determination of the six aflatoxins in various TCMs. For 30 commercial samples analyzed, 16 were contaminated with aflatoxins. The mean levels (incidence) of aflatoxins B1, B2, G1 and G2 in positive samples were 1.40 (68.8%), 1.27 (50.0%), 0.50 (43.8%) and 0.94 (43.8%) μg kg⁻¹, respectively. Interestingly, aflatoxin M1 was detected in two samples with the maximal content of 0.70 μg kg⁻¹. No sample was contaminated with aflatoxin M2. Meanwhile, a possible association between the contamination levels and the selected herbs was clarified in the present study.     

Simultaneous determination of aflatoxin B1, B2, G1, and G2 in corn powder,edible oil,peanut butter,and soy sauce by liquid chromatography with tandem mass spectrometry utilizing turbulent flow chromatography

A novel fully automated method based on dual column switching using turbulent flow chromatography followed by liquid chromatography with tandem mass spectrometry was developed for the determination of aflatoxin B₁, B₂, G₁, and G₂ in corn powder, edible oil, peanut butter, and soy sauce samples. After ultrasound‐assisted extraction, samples were directly injected to the chromatographic system and the analytes were concentrated into the clean‐up loading column. Through purge switching, the analytes were transferred to the analytical column for subsequent detection by mass spectrometry. Different types of TurboFlow^TM columns, transfer flow rate, transfer time were optimized. The limits of detection and quantification of this method ranged between 0.2–2.0 and 0.5–4.0 μg/kg for aflatoxins in different matrixes, respectively. Recoveries of aflatoxins were in range of 83–108.1% for all samples, matrix effects were in range of 34.1–104.7%. The developed method has been successfully applied in the analysis of aflatoxin B₁, B₂, G₁, and G₂ in real samples.     

High performance thin layer chromatographic determination of erythromycin in pharmaceutical preparations

Summary A high performance thin layer chromatographic method was developed for the determination of erythromycin. The drug was separated on a silica gel 60 plate and developed in methanol by means of an automatic multiple development. The chromatogram was sprayed with 10% sulphuric acid solution and heated at 100°C for 10–15 minutes. The area of the spot was quantified by a TLC scanner at a wavelength of 410 nm. A linear calibration curve was established over the range of 4–6 μg in 10μl of erythromycin. The relative standard deviation for five replicate determinations was found to be 1.45% for 5 μg in 10 μl of erythromycin standard. The average percentage recovery was found to be 99.87. The method has been applied to the determination of erythromycin in various pharmaceutical dosage forms. Common excipients in formulations do not interfere. After optimizing the solvent system, it was found that the use of silica gel 60 F₂₅₄ TLC plate with a DVS composed of ethyl acetate, ethanol and 10% sodium acetate pH 9.5 (9:7:8) led to the differentiation and quantitation of erythromycins A, B and C with an R.S.D. of less than 2.0%. The method is simple, precise and inexpensive. It should be used for routine analysis.     

Micro-plate chemiluminescence enzyme immunoassay for aflatoxin B1 in agricultural products

In this work, a micro-plate chemiluminescence enzyme immunoassay by antibody-coated for the determination of aflatoxin B1 (AFB1) in agricultural products has been established. Aflatoxin B1 antibody (AFB1-Ab) was adsorbed physically on polystyrene micro-plate hole as solid phase antibody, which took place immunity-reaction between antigen and antibody with AFB1 standard solution or samples by direct competition. Luminol-hydrogen peroxide chemiluminescence system catalyzed by horseradish peroxidase (HRP) with p-iodophenol enhancement was used as signal detecting system. The effects of several factors, including composition and pH of coating solution, dilution ratio and amount of antibody and enzyme labeled antigen, time of antibody-coating, incubation and chemiluminescence reaction, and other relevant variables upon the immunoasaay were studied and optimized. The linear range of proposed method for AFB1 was 0.05-10.0 ng g⁻¹ with a correlative coefficient of −0.9997. The sensitivity of the proposed method was 0.01 ng g⁻¹. The RSDs of intra- and inter-assay were less than 12.2% and 10.0%, respectively. This method has been successfully applied to the evaluation of AFB1 in agricultural products with recoveries of 79.8%, 101.9% and 115.4% for low, middle and high concentration samples, respectively. It shows a good correlation with the commercial available ELISA kit for AFB1 with correlative coefficient of 0.9098 indicating that the established CLEIA method can be used to determine AFB1 in real samples.     

多孔芳香骨架吸附剂-固相萃取-高效液相色谱法同时测定辣椒粉中4种偶氮类染料

建立了固相萃取-高效液相色谱同时测定辣椒粉中对位红、酸性橙Ⅱ、苏丹红Ⅰ和苏丹红Ⅱ 4种偶氮染料的方法。以多孔芳香骨架-6（PAF-6）材料作为固相萃取吸附剂，考察并获得了影响自制固相萃取柱的萃取效率和吸附容量等主要因素。在优化条件下，4种目标分析物的检出限（LOD）为1.5~7.0 μg/L（信噪比S/N=3），定量限（LOQ）为5.0~22.1 μg/L（S/N=10），加标回收率为76.5%~89.8%，相对标准偏差（RSD）均不大于5.3%（n=6）。此外，基于量子化学计算，考察了PAF-6与目标分析物之间的相互作用机制，结果表明，目标分析物可以稳定地吸附在PAF-6分子上。该方法准确可靠，具有良好的回收率和较高的灵敏度，可用于辣椒粉中4种偶氮类染料的检测。     

超高效液相色谱法快速测定发酵茶叶中的黄曲霉毒素

建立了用超高效液相色谱/紫外检测器测定发酵茶叶中黄曲霉毒素B1、B2、G1和G2的方法.用CH2Q2提取黄曲霉毒素,提取液经浓缩后,用LC-CN固相萃取小柱净化,超高效液相色谱测定.在浓度范围20～200μg/L(B1、G1),15～120μg/L(B2、G2)内具有良好的线性相关关系.黄曲霉毒素的回收率为81.4%～92.3%,相对标准偏差RSD 1.6%～4.2%.检出限为0.32μg/kg(B1、G1),0.18μg/kg(B2、G2)(S/N=3).     

浸渍硅胶薄层色谱板分离钴和镍及数字图像分析法定量(英文)

Thin layer chromatography(TLC) of cobalt and nickel has been performed on silica gel layers induced with alkali mediated cellulose extract.A novel combination of 10% aqueous solutions of Tween-20 and potassium thiocyanate in 1∶1(v/v) was identified as the best mobile phase for the selective separation of Co2+from Ni2+on the impregnated Silica Gel G layers.The chromatographic characteristics of the cations were studied and the limits of detection as well as the limits of quantification for Co2+and Ni2+were determined.The quantitative estimation of the cations was achieved from the digital image analysis of respective chromatograms.The proposed quantitative method was successfully applied with 0-0.50% error for the determination of Co2+from Ni2+in spiked samples of bauxite,soil and rock containing common cations such as Al3+,Fe2+,Ti4+,Zn2+,Mn2+,Cu2+,Cr6+,Mg2+,etc.under the optimized chromatographic conditions.     

免疫亲和-光化学衍生高效液相色谱检测花生及花生制品中黄曲霉毒素

建立了免疫亲和柱净化、柱后光化学衍生、高效液相色谱法结合荧光检测器测定花生及花生制品中黄曲霉毒素的新方法。方法的检出限为0.25μg/kg,相对标准偏差低于10%,回收率为64%~101%。该方法简便快速、灵敏准确、重复性好,满足出入境检验检疫工作的需要。     

Large-scale purification of the mycotoxins aflatoxin B1, B2 and G1

The isolation and purification of gram quantities of the important mycotoxins aflatoxin B1, B2 and G1 are described. The method involves final purification on a Waters Prep LC-500 instrument, loaded with silica cartridges, and elution with chloroform.     

Extraction chromatographic studies of Ti(IV) with cyanex 301 as impregnant—Recovery from red mud

Summary A silica gel column impregnated with bis-(2,4,4-trimethylpentyl)dithiophosphinic acid has been studied for the uptake of Ti(IV). Its chemical stability has been examined and its regeneration power checked. The stoichiometry of the extracted species is proposed and the loading capacity of the column material for Ti(IV) assessed. Some important binary separations of Ti(IV) from commonly associated metal ions have been achieved and the column has been used to recover high-purity titanium from red mud, a secondary sector material.     

色谱分析中离子液体的应用及其测定

离子液体作为一种优良的溶剂越来越受到人们的关注。由于离子液体特殊的物理化学性质使其在色谱分析中也得到了较广泛的应用。本文综述了离子液体在气相色谱、高效液相色谱和毛细管电泳中的应用,其中包括离子液体作为气相色谱的固定相、高效液相色谱的固定相及流动相添加剂和毛细管电泳的电解质添加剂等,并对离子液体的色谱分离检测作了详细介绍。     

固相萃取-高效液相色谱/串联质谱检测谷物中黄曲霉毒素B1、B2、G1、G2和M1

建立了高效液相色谱/串联质谱(LC-MS/MS)同时检测谷物中的黄曲霉毒素B1、B2、G1、G2和M1的方法.并优化了液相色谱条件和质谱的相关参数.谷物样品经研磨成粉末后,直接经甲醇-水( V∶V=10∶90)提取,Oasis HLB固相萃取净化,乙腈-水(0.2％甲酸)梯度洗脱,选择电喷雾离子源(ESI),正离子扫描...     

Stability-indicating high performance thin layer chromatography determination of Paroxetine hydrochloride in bulk drug and pharmaceutical formulations

A simple selective precise and stability-indicating high performance thin layer chromatographic method of analysis of Paroxetine hydrochloride both as a bulk drug and in formulations was developed and validated. The method employed TLC (Thin Layer Chromatography) aluminum precoated with silica gel 60F-254 as the stationary phase. The solvent system consisted of butanol:acetic acid:water (8:2:0.5, v/v/v). This system was found to give compact spots for Paroxetine HCl (Rf, retardation factor, value-0.48 ± 0.02). Paroxteine HCl was subjected to acid and alkali hydrolysis, oxidation and photodegradation, where the degraded product was well separated from the pure drug. Densitometric analysis of Paroxetine hydrochloride was carried out in the absorbance mode at 295 nm. The linear regression analysis data for the calibration spots showed good relationship with (regression) r² = 0.9903 in the amount range of 300-1500 ng (nanogram) per spot. The mean value of co-relation co-efficient, slope and intercept were 0.9903 ± 0.001, 5.38 ± 0.058 and 182.5 ± 2.16 respectively. The method was validated for precision, recovery and robustness. The limits of detection and quantitation were 50 and 150 ng, respectively. The drug doesnot undergo degradation with oxidation, but gets affected in acidic and alkaline conditions. The acid and alkali degradation showed extra peaks at 0.4 and 0.08 Rf, respectively. This indicates that the drug is susceptible to acidic and alkaline medium. As the method could effectively separate the drug from its degradation products, it can be employed as a stability-indicating one.     

Enhanced synchronous spectrofluorimetric determination of aflatoxin B1 in pistachio samples using multivariate analysis

The determination of aflatoxin B₁ (AFB1) in pistachio has been accomplished by normal and synchronous fluorimetry in combination with some multivariate calibration methods and derivative techniques. Extending the two-dimensional synchronous fluorescence scan to a three-dimensional total synchronous fluorescence scan was used to obtain the optimized Δλ for AFB1 in pistachio sample. The methods are based on the enhanced fluorescence of AFB1 by β-cyclodextrine in 10% (v/v) methanol-water solution. Twenty-six pistachio samples containing AFB1 in the range 0-15 ppb were used as calibration set. Eighteen combinational methods were tested to make best model for prediction of AFB1 and finally best results obtained using a method based on synchronous fluorimetry in combination with multiple linear regressions (MLR). For concentrations ranging from 0 to 15 ppb of AFB1 in 22 pistachio samples as prediction set, the values of root mean square difference (RMSD) and relative error of prediction (REP) using MLR were 0.328 and 4.453%, respectively were observed. Two naturally contaminated pistachio samples were analyzed by synchronous fluorimetry using MLR and compared with HPLC results.     

加压薄层色谱法的原理及其应用

对加压薄层色谱的原理和应用作以介绍。介绍了加压薄层色谱的仪器结构、工作方式;对影响加压薄层色谱的因素、常见问题及解决方法进行了总结;简要地介绍了该方法在分析中的应用情况。