First Determination of Glycidyl Ester Species in Edible Oils by Reverse-Phase Ultra-Performance Liquid Chromatography Coupled with an Evaporative Light-Scattering Detector

In this work, a new ultra-performance liquid chromatograph-evaporative light-scattering detector (UPLC-ELSD) method for quantitation of glycidyl esters (GE) contents in edible oils is presented. The method features complete separation of five GE species within 20 min by a C18 column and gradient elution with a mobile phase consisting of 85% and 2.5% methanol aqueous solutions. The coefficients of regression (R²) were all ≥0.9999 for the linear-quadratic regression curves of GE species in a concentration range of 5~80 μg/mL. The intraday and interday recoveries (%) of GE species in solvent were in a range of 81.3~107.3%, and the intraday and interday coefficients of variation (CVs, %) were all ≤8.6%. The average recovery (%) of GE species spiked in extra-virgin olive oil samples ranged from 88.3~107.8% and the intermediate precision (CV, %) of ≤14% indicated acceptable accuracy and precision. The method exhibited limit of quantification (LOQ) for each GE species (0.6 μg glycidol equivalents/g oil). The method was applied to determine GE concentrations of six commercial oil samples, and total glycidol equivalents were consistent with data obtained by GC-MS method. This UPLC-ELSD method could be adopted for precursory screening and research purposes to improve food safety when MS detectors are unavailable.     

Remediation of lead by pretreated red algae: adsorption isotherm,kinetic, column modeling and simulation studies

Batch and column biosorption experiments were carried on for lead uptake using ecofriendly biosorbents (raw and calcium chloride [CaCl₂] or formaldehyde pretreated form of red marine algae Jania ruben [Linnaeus]). The best-fit (linear and nonlinear) isotherms, kinetics, and column adsorption models were identified using statistical analysis. Freundlich, Langmuir, Temkin, Redlich–Peterson, and Elovich adsorption isotherm models were tested. Highest adsorption capacity (774 mg/g) has been observed with Jania algae pretreated with formaldehyde. Pseudo-first- and second-order adsorption kinetics were applicable. The column capacity for lead removal with Jania pretreated with CaCl₂ was found to be 1089.6 (mg/g) from the breakthrough curve area method. Thomas, Yoon-Nelson, Yan, and Clark column models were tested with regression analysis. Thomas model is the best column model with capacity q_Th = 1092.4 mg/g. Overall, 98.5% regeneration of column was achieved, indicating the suitability of using algae materials in multioperational cycles. Adsorbed lead present in algae material was confirmed by thermal analysis.     

Enantiomeric separation of indoxacarb on an amylose‐based chiral stationary phase and its application in study of indoxacarb degradation in water

Direct semipreparative enantioseparation of indoxacarb was performed on a semipreparative Chiralpak IA column using normal‐phase high‐performance liquid chromatography (HPLC) with n‐hexane–isopropanol–ethyl acetate (70:20:10) mixture as mobile phase. Degradation of indoxacarb (2.33S + 1R) and its two enantiopure isoforms in three aqueous buffer solutions and four water samples collected from natural water sources was then elucidated by HPLC analysis on Chiralpak IA column. Degradation of all three indoxacarbs complied with first‐order kinetics and demonstrated linearity with regression coefficients R² > 0.88. Indoxacarb (2.33S + 1R) underwent enantioselective degradation in river water, rain water, and buffer solution of pH 7.0. Enantiopure S‐(+)‐indoxacarb and R‐(?)‐indoxacarb were both found to be configurationally stable in water. Copyright © 2014 John Wiley & Sons, Ltd.     

硼酸亲和杂化毛细管整体柱选择性富集蒲公英中的活性物质

以四乙氧基硅烷,N-氨乙基-3-氨丙基三乙氧基硅烷,3-甲基丙烯酰氧丙基三甲氧基硅烷作为前驱,4-乙烯基苯硼酸为单体,在毛细管中原位制备硼酸亲和杂化整体柱,该柱可在中性条件下选择性的富集顺式二羟基生物分子,实现了对蒲公英中活性成分咖啡酸及绿原酸的选择性富集。     

Introduction of Fluorometry to the Screening of Protein Crystallization Buffers

A system to use fluorometry for the search of protein crystallization buffers was developed. The screening of candidates was done with a use of short gel-filtration column (Sephacryl S-100 HR) linked to the fluorometer. Protein elution was monitored by intrinsic fluorescence or emission from its labels. This method was applied to actin and actin complexes. When nuclei were formed in actin solution, preceding the peak of actin, a new peak appeared on the elution curve. It was found that the fluorescence allows detection of even small amount of nuclei formed in the buffer. Using the screened buffers, crystal growths were attempted. The images of crystals were captured by fluorescence microscope. The monitoring of nuclei with this method will accelerate the screening of crystallization buffers. This system is applicable to the crystallization of other proteins and their complexes.     

Gottfried Kränzlin,the first follower of Tswett

Summary This paper summarizes the work of Gottfried Kränzlin, who, in 1906–1908, was the first after Tswett to utilize chromatography for the investigation of plant pigments.     

Demonstration of an optimized flow cell SFC-FTIR interface

Summary An on-line application of capillary SFC-FTIR for the analysis of five steroids has been demonstrated. Baseline resolution is achieved for all the components of the mixture and IR spectra are obtained which match well with spectra of the neat materials. Also, the injected minimum detectable quantity (IMDQ) of caffeine (approximately 2 ng) under similar chromatographic conditions is demonstrated for this interface. Very low IMDQ's achieved using this flow cell interface will facilitate the use of this technique for the analysis of biological fluids and other materials where very low detection limits are required.     

Scale-up of “myxalin” purification by a pseudoaffinity method using a radial flow column

Summary Myxalin is a newly defined bacterial anticoagulant. It has been previously purified on Histidyl-Sepharose, on a small scale. We describe a scale-up of this procedure using a radial flow column (Sepragen^?). This design permits the use of the same soft gel matrix with 15-fold increase in flow rate compared to the linear system and a simple extrapolation of the operating conditions when optimized on a smaller scale gave no decrease in resolution. There are moreover, better activity yields and very interesting economic advantages.     

外加磁场、电流及弧柱半径对电弧螺旋不稳定性的影响

采用与时间有关的线性微扰理论，研究了存在气流作用下，外加磁场、弧电流以及弧柱半径对电弧螺旋不稳定性的影响，给出了稳定性条件和不稳定性增长率等定量结果. 关键词： 电弧 稳定性 轴向磁场 弧柱半径