Analysis of free and esterified sterols in vegetable oil methyl esters by capillary GC

The introduction of quality standards for vegetable oil methyl esters is gaining in importance due to their increased use as diesel fuel substitutes and as technical products. Free and esterified sterols, the main constituents of the unsaponifiable matter in vegetable oils, are recovered in vegetable oil methyl esters and may influence the technical properties of vegetable oil methyl ester products. A rapid gas chromatographic method for the qualitative and quantitative determination of free and esterified sterols in vegetable oil methyl esters has therefore been developed. The concentration of the free sterols as well as their qualitative and quantitative composition and the concentration of the sterol esters have been determined in rape seed oil methyl ester samples by GC–FID. Prior to analysis, the free sterols were silylated with N,O-bis(trimethylsilyl)trifluoroacetamide with 1% of trimethylchlorosilane; betulinol was used as an internal standard. Calibration was performed by analysis of standard solutions containing β-sitosterol, cholesteryl stearate, and betulinol. The reproducibility of the quantitative results has been evaluated by repeated injections of the same test solution and by repeated complete analysis of the same sample.     

双活性磺酸基蔗渣木聚糖对羟基苯甲酸酯的合成及活性模拟

以蔗渣木聚糖(BX)为主要原料、氨基三磺酸钠为酯化剂,在一步酯化合成磺酸基蔗渣木聚糖酯的基础上,利用磺酸基蔗渣木聚糖酯和对羟基苯甲酸进行二步酯化反应,合成了磺酸基蔗渣木聚糖对羟基苯甲酸酯,并考察了反应条件对酯化反应的影响,通过单因素实验确定了第二步酯化反应较佳的合成工艺条件.蔗渣木聚糖酯化改性前后的样品分别用FT-IR,DG-DTG和XRD进行了表征,并对该双酯化衍生物的分子进行了优化与活性模拟.结果表明:FT-IR证明双酯化产物含有磺酸基团和对羟基苯甲酸酯基团,TG-DTG分析表明该双酯化衍生物的热稳定性提高,XRD说明发生双酯化改性后分子排列的规整性提高,结晶度增加;活性模拟实现了磺酸基蔗渣木聚糖对羟基苯甲酸酯与艾滋病毒的对接.     

Formulation of Environmentally Safe Graffiti Remover Containing Esterified Plant Oils and Sugar Surfactant

The removal of graffiti or over-painting requires special attention in order to not induce the surface destruction but to also address all of the important eco-compatibility concerns. Because of the necessity to avoid the use of volatile and toxic petroleum-based solvents that are common in cleaning formulations, much attention has recently been paid to the design of a variety of sustainable formulations that are based on biodegradable raw materials. In the present contribution we propose a new approach to graffiti cleaning formulations that are composed of newly synthesized green solvents such as esterified plant oils, i.e., rapeseed oil (RO), sunflower oil (SO), or used cooking oil (UCO), ethyl lactate (EL), and alkylpolyglucosides (APGs) as surfactants. Oil PEG-8 ester solvents were synthesized through the direct esterification/transesterification of these oils using monobutyltin(IV) tris(2-ethylhexanoate) and titanium(IV) butoxide catalysts under mild process conditions. The most efficient formulations, determined by optimization through the response surface methodology (RSM) was more effective in comparison to the reference solvents such as the so-called Nitro solvent (denoting a mixture of toluene and acetone) and petroleum ether. Additionally, the optimal product was found to be effective in removing graffiti from glass, metal, or sandstone surfaces under open-field conditions in the city of Wrocław. The performed studies could be an invaluable tool for developing future green formulations for graffiti removal.     

Upgrading poly(butylene succinate)/wood fiber composites by esterified lignin

Aliphatic chains were introduced into the macromolecule of kraft lignin using aliphatic chlorides as esterification reagents. The hydrophobicity of esterified lignin (EL) was enhanced as compared to the original lignin. EL was further used as a macromolecular coupling agent in poly(butylene succinate)/chemi-thermomechanical pulp fiber composites. As a result, the composites with enhanced mechanical performance were obtained, and the tensile strength, impact strength, and bending strength were increased by 25.1, 22.4, and 19.3%, respectively, under 2 wt% EL-treatment (synthesized by palmitoyl chloride, –COCl/–OH = 1.5:1) in comparison with those of the specimen without any coupling agent treatment. Furthermore, the composite prepared with EL-treated fibers shows significant lower water absorption ratio than that of untreated one. A significant increase in storage modulus (E′) was observed upon the incorporation of treated fibers. Furthermore, the improved interfacial bonding between treated fibers and matrix was verified by SEM images. The shear viscosity of composite was increased by the incorporation of EL, but in general, the rheological behaviors of composites are not significantly changed.     

Serum fatty acid profiles and potential biomarkers of ankylosing spondylitis determined by gas chromatography–mass spectrometry and multivariate statistical analysis

Ankylosing spondylitis (AS) is a common chronic inflammatory rheumatic disease. Early and accurate detection is essential for effective disease treatment. Recently, research has focused on genomics and proteomics. However, the associated metabolic variations, especially fatty acid profiles, have been poorly discussed. In this study, the gas chromatography–mass spectrometry (GC‐MS) approach and multivariate statistical analysis were used to investigate the metabolic profiles of serum free fatty acids (FFAs) and esterified fatty acids (EFAs) in AS patients. The results showed that significant differences in most of the FFA (C12:0, C16:0, C16:1, C18:3, C20:4, C20:5, C22:5 and C22:6) and EFA (C12:0, C16:1, C18:0, C18:1, C18:2, C18:3, C20:4 and C22:6) concentrations were found between the AS patients and healthy controls (p < 0.05). Principal component analysis and partial least squares discriminant analysis were performed to classify the AS patients and controls. Additionally, FFAs C20:4, C12:0, C18:3 and EFAs C22:6, C12:0 were confirmed as potential biomarkers to identify AS patients and healthy controls. The present study highlights that differences in the serum FFA and EFA profiles of AS patients reflect the metabolic disorder. Moreover, FFA and EFA biomarkers appear to have clinical applications for the screening and diagnosis of AS. Copyright © 2014 John Wiley & Sons, Ltd.     

The McLafferty rearrangement in the Glu residue in a cyclic lipopeptide determined by Q-TOF MS/MS

The intraresidue rearrangement and loss of the side chain of the Glu residue was found through MS/MS analysis of both original and methanol-esterified lipopeptides. Both Glu and Asp residues in the cyclic lipopeptide were esterified. The MS/MS results showed that the loss of fragment 72 or 86 was induced by McLafferty-type rearrangement from the Glu or esterified Glu. The mechanism of loss of the Glu residue can be used to determine or to corroborate the existence of the Glu and to help understand the fragment formation in MS/MS. The cleavage mechanism and m/z intensities imply that the sodium ion was easier attached and the cleavage would easily occur at specific sites.     

微细化交联木薯淀粉醋酸酯的制备与研究

本文以三偏磷酸钠为交联剂,醋酸酐为酯化剂,采用先交联、后酯化,先酯化、后交联,两种方案对木薯淀粉进行改性,并对木薯淀粉醋酸酯进行微细化处理。利用IR、SEM、XRD和TGA对合成产物进行表征;并对其冷热粘度进行了研究。结果表明,理想合成路线为:先酯化,后交联合成交联木薯淀粉醋酸酯。通过机械球磨,能有效地将木薯淀粉颗粒微细化,并可通过球磨时间控制淀粉颗粒的粒度和形貌。测试表明,微细化交联木薯淀粉醋酸酯的耐热性下降、结晶度下降;冷粘度增高,但热粘度性质有所下降。     

酯化型环氧化合物摩擦成膜对润滑油摩擦学性能影响之研究

用油酸和环氧树脂合成了一种能够形成摩擦聚合膜的酯化型环氧化合物润滑油添加剂——DE成膜剂。以液体石蜡或二线油为基础油,在栓-盘式试验机和四球试验机上就DE成膜剂对润滑油摩擦学性能的影响进行了研究。结果表明,添加DE成膜剂明显地改善了润滑油的摩擦学性能;在基础油中加入DE成膜剂比加环氧树脂、脂肪酸酯或油酸时的摩擦系数低、表面擦伤少、承载能力高、磨损量小。文章还对DE成膜剂在摩擦表面上形成的摩擦聚合膜的作用机制进行了分析和探讨。     

酯化淀粉的研究进展

对淀粉进行酯化改性可以改善淀粉的性能,从而提高其应用范围.综述了不同种类酯化淀粉的制备,包括酯化剂的种类、酯化方法,评价不同种类、取代度的酯化淀粉的性能以及应用性能,并预测了其今后的发展趋势.