Separation and characterization of peanut phospholipid molecular species using high-performance liquid chromatography and fast atom bombardment mass spectrometry

Total lipid extracts from peanut seed were separated on a silica column into a triacylglycerol fraction and a polar lipid fraction by high-performance liquid chromatography (HPLC). The polar fraction containing the phospholipids was retained on the precolumn, and the triacylglycerol fraction was eluted to a waste flask by a special valve arrangement. Phospholipids were eluted from the precolumn and separated into various classes on a silica analytical column. Each phospholipid class was manually collected and subsequently subjected to reversed-phase HPLC in tandem with a fast atom bombardment mass spectrometer. Phosphatidylethanolamine was separated into five molecular species. Phosphatidylinositol and phosphatidylcholine were each separated into six molecular species.     

Column Selection for Biomedical Analysis Supported by Column Classification Based on Four Test Parameters

This article focuses on correlating the column classification obtained from the method created at the Katholieke Universiteit Leuven (KUL), with the chromatographic resolution attained in biomedical separation. In the KUL system, each column is described with four parameters, which enables estimation of the F_KUL value characterising similarity of those parameters to the selected reference stationary phase. Thus, a ranking list based on the F_KUL value can be calculated for the chosen reference column, then correlated with the results of the column performance test. In this study, the column performance test was based on analysis of moclobemide and its two metabolites in human plasma by liquid chromatography (LC), using 18 columns. The comparative study was performed using traditional correlation of the F_KUL values with the retention parameters of the analytes describing the column performance test. In order to deepen the comparative assessment of both data sets, factor analysis (FA) was also used. The obtained results indicated that the stationary phase classes, closely related according to the KUL method, yielded comparable separation for the target substances. Therefore, the column ranking system based on the F_KUL-values could be considered supportive in the choice of the appropriate column for biomedical analysis.     

新试剂2－（6－甲基－2－苯并噻唑偶氮）－5－二乙氨基酚反相高效液相色谱快速分析钌、铑、钯和钴

报道了以新试剂２－（６－甲基－２－苯并噻唑偶氮）－５－二乙氨基酚（ＭＢＴＡＥ）作柱前衍生化试剂，反相高效液相色谱分离并测定轻铂族元素钌（Ⅲ）、铑（Ⅲ）和钯（Ⅱ）以及过渡元素钴（Ⅱ）。各金属离子的检出限分别为（ｎｇ／ｍＬ）：Ｒｕ１．６０，Ｒｈ０．４７，Ｐｄ０．１２，Ｃｏ０．１５。此方法分离贵金属具有分析时间短，灵敏度高等优点。     

A Study of the Separation Efficiency in the Concentric-Tube Countercurrent Separation Process under Generalized Linear Applied Fields and with Recycles at Both Ends

Abstract

The mathematical model for the separation of binary mixtures has been extended to a concentric-tube continuous-contact countercurrent column under generalized linear external fields and with recycles at both ends. An analytical solution is obtained by use of the orthogonal expansion method. Numerical results for separation in a thermal diffusion column are also illustrated.     

Metal-organic frameworks for analytical chemistry: from sample collection to chromatographic separation

In modern analytical chemistry researchers pursue novel materials to meet analytical challenges such as improvements in sensitivity, selectivity, and detection limit. Metal-organic frameworks (MOFs) are an emerging class of microporous materials, and their unusual properties such as high surface area, good thermal stability, uniform structured nanoscale cavities, and the availability of in-pore functionality and outer-surface modification are attractive for diverse analytical applications. This Account summarizes our research on the analytical applications of MOFs ranging from sampling to chromatographic separation. MOFs have been either directly used or engineered to meet the demands of various analytical applications. Bulk MOFs with microsized crystals are convenient sorbents for direct application to in-field sampling and solid-phase extraction. Quartz tubes packed with MOF-5 have shown excellent stability, adsorption efficiency, and reproducibility for in-field sampling and trapping of atmospheric formaldehyde. The 2D copper(II) isonicotinate packed microcolumn has demonstrated large enhancement factors and good shape- and size-selectivity when applied to on-line solid-phase extraction of polycyclic aromatic hydrocarbons in water samples. We have explored the molecular sieving effect of MOFs for the efficient enrichment of peptides with simultaneous exclusion of proteins from biological fluids. These results show promise for the future of MOFs in peptidomics research. Moreover, nanosized MOFs and engineered thin films of MOFs are promising materials as novel coatings for solid-phase microextraction. We have developed an in situ hydrothermal growth approach to fabricate thin films of MOF-199 on etched stainless steel wire for solid-phase microextraction of volatile benzene homologues with large enhancement factors and wide linearity. Their high thermal stability and easy-to-engineer nanocrystals make MOFs attractive as new stationary phases to fabricate MOF-coated capillaries for high-resolution gas chromatography (GC). We have explored a dynamic coating approach to fabricate a MOF-coated capillary for the GC separation of important raw chemicals and persistent organic pollutants with high resolution and excellent selectivity. We have combined a MOF-coated fiber for solid-phase microextraction with a MOF-coated capillary for GC separation, which provides an effective MOF-based tandem molecular sieve platform for selective microextraction and high-resolution GC separation of target analytes in complex samples. Microsized MOFs with good solvent stability are attractive stationary phases for high-performance liquid chromatography (HPLC). These materials have shown high resolution and good selectivity and reproducibility in both the normal-phase HPLC separation of fullerenes and substituted aromatics on MIL-101 packed columns and position isomers on a MIL-53(Al) packed column and the reversed-phase HPLC separation of a wide range of analytes from nonpolar to polar and acidic to basic solutes. Despite the above achievements, further exploration of MOFs in analytical chemistry is needed. Especially, analytical application-oriented engineering of MOFs is imperative for specific applications.     

亲水作用液相色谱串联质谱法测定糙米中春雷霉素残留量

建立了糙米中春雷霉素残留量的亲水作用色谱–质谱联用测定方法。样品用甲醇+水(体积比为9∶1)提取,经HLB和SCX固相萃取小柱净化,以HWaters HPLC BEH HILIC色谱柱H(50mm×2.1 mm,1.7 m)分离,采用UPLC–MS/MS多反应监测(MRM)正离子模式测定,外标法定量。春雷霉素最低检测浓度为0.005 mg/kg,在0.005,0.050,0.100 mg/kg 3个添加水平下,平均回收率为74.9%～82.7%,相对标准偏差为4.9%～6.9%。     

采用串联双柱-反吹气相色谱系统测定汽油中苯含量

采用一个有串联双柱-反吹系统的气相色谱仪分析检测汽油中的苯含量。样品组分首先进入一非极性的预切柱按沸点高低顺序分离,通过切换六通阀反吹放空重组分,使辛烷及轻烃组分进入具有强极性的TCEP分析柱,芳烃和非芳烃经分离后进入TCD检测器。该方法确定了最佳阀切换反吹时间和操作条件,以丁酮为内标物,通过建立苯的校正曲线定量计算样品中苯的体积浓度。实验的回收率在93.8%~99.1%,方法的相对标准偏差(RSD)≤2.45%。     

A rapid gas chromatographic method for the determination of BHA and BHT in vegetable oils

A gas liquid chromatographic (GLC) technique has been developed which requires about 20 min for the determination of BHA and BHT in vegetable oils. This method involves the addition of an internal standard to a weighed portion of the oil, dilution of the mixture with carbon disulfide, and injection into the Gas Chromatograph. BHA and BHT are isolated from the nonvolatile vegetable oil by using a short precolumn located in the sample port block of the gas chromatograph. Up to 35 consecutive sample injections per day have been made on the same precolumn with no appreciable effect on the accuracy of the determination. The precolumn is cleaned at the end of each day’s operation. The clean precolumn is allowed to equilibrate to sample port block temperature overnight for the following day’s analysis. Identification of BHA and BHT can be confirmed with a second GLC column which reverses the elution order of these compounds. Soybean, cottonseed, corn and peanut oils fortified with 20, 60 and 100 ppm each of BHA and BHT showed a recovery range of 97% to 104%.     

Analysis of Low Molecular Weight Lignin-Derived Sulphonates by Capillary Zone Electrophoresis

A fast and simple analytical procedure, based on capillary zone electrophoresis (CZE), for separation of underivatized low molecular weight lignin-derived sulphonates has been developed. Optimal CZE-operatipn conditions for the separation and detection of several lignin-derived sulphonic acids was found when using a low pH (pH 1.7) phosphate buffer system, an applied voltage of 20 kV and UV-detection at the anode-side. At these conditions the electroosmotic flow is negligible and the analytes are transported through the capillary column by electromigration. The sulphonation and subsequent degradation of the lignin-model compound 1-(4-hydroxy-3-methoxyphenyl)-2-O-(2-methoxyphenyl)-glycerol has been studied by CZE-analysis of aliquots taken from a sulphite reaction mixture No sample pretreatment was needed before analyzing the sulphite reaction mixture with CZE. The method has also been found to be useful for detection of sulphonic acids in samples from sulphite cooking. Crude extracts of a sulphite cooking liquor could be directly analysed by using the technique developed. Based on migration time data and comparison with an authentic sample, 1-(4-hydroxy-3-meth6xyphenyl)-prop-2-ene-1-sulphonate was identified as one of the sulphonic acids present in the sulphite cooking liquor.     

葡萄糖直接发酵产2-酮基-L-古龙酸途径中代谢产物的HPLC分析

建立了利用高效液相色谱对葡萄糖发酵产2-酮基-L-古龙酸体系中的4种代谢产物D-葡萄糖酸、2-酮基-D-葡萄糖酸、2,5-二酮基-D-葡萄糖酸和2-酮基-L-古龙酸的定量测定方法,分析条件为：300 mm′7.8 mm Aminex HPX-87H柱,柱温30℃,流动相为50 mmol/L硫酸,流速0.2 mL/min,RID-10A示差检测器,以丙二酸为内标物. 结果表明,4种物质分离较好. 该方法对2-酮基-D-葡萄糖酸、2,5-二酮基-D-葡萄糖酸和2-酮基-L-古龙酸3种代谢物的检测平均误差分别为1.53%, 0.89%和1.84%.     

高效液相色谱-串联质谱法同时检测蔬菜、水果中21种农药多残留

建立了以固相萃取/高效液相色谱-串联质谱(LC/MS/MS)同时测定蔬菜、水果中痕量21种农药残留量的方法.蔬菜、水果样品提取液经固相萃取后采用C18柱分离,以0.1%甲酸乙腈-0.1%甲酸水溶液为流动相,梯度洗脱,以保留时间和质荷比对分离出的组分予以定性确证,用峰面积进行定量.结果表明,21种农药的质量浓度与其峰面积在一定的范围内呈良好的线性关系,样品中最低检出质量分数为0.0005～0.003 mg/kg,样品的平均加标回收率为76.34%～119.33%.方法简便、快速、灵敏,适用于蔬菜、水果中这些农药的同时分析.     

A RIGOROUS ANALYSIS OF McCABE-THIELE ASSUMPTIONS AND THEIR CONSEQUENCES: CRITICAL ROLE OF PARALLEL ENTHALPY LINES

The assumptions and results associated with the McCabe-Thiele method of distillation column analysis are brought together within a rigorous analytical framework. Within this framework, the assumption that the saturated liquid and vapor enthalpy curves are parallel lines, apart from adiabatic and isobaric operation of the distillation column, is shown to be sufficient to derive all the major results of the McCabe-Thiele method including the constant molar overflow condition. Then, using a rigorous thermodynamic analysis, a comprehensive set of conditions sufficient for the enthalpy curves to be parallel lines are obtained. Some common systems for which these assumptions hold are discussed. Finally, the conditions under which McCabe-Thiele-like methods occur in other separation processes are outlined, with pointers to a unified picture of separation processes.     

An Optimized MRM-Based Workflow of the l-Arginine/Nitric Oxide Pathway Metabolites Revealed Disease- and Sex-Related Differences in the Cardiovascular Field

Clinical data indicate that low circulating l-homoarginine (HArg) concentrations are associated with cardiovascular (CV) disease, CV mortality, and all-cause mortality. A high number of LC-based analytical methods for the quantification of HArg, in combination with the l-arginine (Arg)-related pathway metabolites, have been reported. However, these methods usually consider a limited panel of analytes. Thus, in order to achieve a comprehensive picture of the Arg metabolism, we described an improved targeted metabolomic approach based on a multiple reaction monitoring (MRM) mass spectrometry method for the simultaneous quantification of the Arg/nitric oxide (NO) pathway metabolites. This methodology was then employed to quantify the plasma concentrations of these analytes in a cohort of individuals with different grades/types of coronary artery disease (CAD) in order to increase knowledge about the role of HArg and its associated metabolites in the CV field. Our results showed that the MRM method here implemented is suitable for the simultaneous assessment of a wide panel of amino acids involved in the Arg/NO metabolic pathway in plasma samples from patients with CV disease. Further, our findings highlighted an impairment of the Arg/NO metabolic pathway, and suggest a sex-dependent regulation of this metabolic route.     

2,4-二硝基氟苯柱前衍生化法测定普瑞巴林

利用2,4-二硝基氟苯为柱前衍生剂,建立了用高效液相色谱法测定普瑞巴林的方法。考察了光、反应温度、摩尔比和反应时间对衍生化反应的影响,确定了最佳衍生反应条件:在65℃水浴中避光反应75min。色谱柱为C18,流动相为50mmol·L-1KH2PO4(pH=3.0)/乙腈(30/70,v/v),检测波长为360nm,流速为1.0mL·min-1,柱温为35℃。实验结果:在8～48μg·mL-1范围内呈较好的线性关系(r=0.9998),回收率(100.03±1.10)%(n=9),不同浓度下日内精密度0.82%、0.77%和1.87%,8h内稳定性良好(RSD=1.92%),检测限低至0.8ng·mL-1。实验表明该方法简便、快速、准确、灵敏。通过对该方法的实际应用,三批样品测定值的RSD分别为0.59%、0.68%和1.04%,表明该方法能够用于测定普瑞巴林的含量。     

柱前衍生化高效液相色谱法拆分1,1′-联-2-萘酚光学异构体

以(S)-(+)-樟脑磺酰氯作柱前手性衍生化试剂,与外消旋1,1′-联-2-萘酚反应,形成非对映异构体联二萘酚樟脑磺酸酯,再用反相高效液相色谱进行分离。结果表明,采用Zorbax XDB-C8和HypersilODS(C18)柱,流动相V(甲醇)∶V(水)分别为75∶25和85∶15,流速均为1mL/min时,分离度分别为1.86和1.74,有效地分离了两个非对映异构体。进一步水解得到光学纯(R)-1,1′-联-2-萘酚和(S)-1,1′-联-2-萘酚,ee值均达99%以上。     

A quality control procedure for the gas liquid chromatographic evaluation of the flavor quality of vegetable oils

An objective procedure which is relatively simple and rapid is under study for the determination of the flavor quality of vegetable oils. This procedure utilizes the direct injection of an oil sample to which has been added an internal standard, into a packed precolumn of a gas Chromatograph. The volatiles are swept from the precolumn through a 10% SE-30 column under operating parameters which permit complete elution of all volatiles and internal standard within 20 min. Some 1 5 to 20 samples can be evaluated in one day before it is necessary to replace any part of the foot-long precolumn. Evaluations have been made by the gas liquid Chromatographic (GLC) procedure and by a flavor panel of oil samples subjected to a variety of storage conditions. Generally, differences in the GLC pattern are reflected in the flavor panel results. ted at the AOCS Meeting, New Orleans, April 1976.     

High-resolution capillary zone and gel electrophoresis of structurally similar amphipathic glutathione conjugates based on interaction with beta-cyclodextrins

The tripeptide glutathione is a prominent intracellular constituent that provides protection against genotoxic and carcinogenic electrophiles and is also a component of several biological signal substances. Glutathione conjugates, free glutathione, and glutathione disulfide contain charged amino acid residues, which contribute to solubility in aqueous media. However, the amphipathic nature of glutathione conjugates and the small differences that may distinguish the S substituents, pose analytical problems in their resolution. The present study demonstrates how homologous S-alkyl and S-benzyl conjugates of high structural similarity can be efficiently resolved by capillary electrophoresis. Inclusion of beta-cyclodextrins in the buffer or in a polyacrylamide gel affords baseline separation of the analytes. The separation methods described are applicable to enzyme assays in vitro and to the identification and quantification of glutathione conjugates of importance in toxicology and physiology. The contribution of beta-cyclodextrin to the separation is primarily based on interactions between its hydrophobic cavity and the S-alkyl and S-benzyl groups of the analytes.     

在线固相萃取-二维高效液相-串联质谱法测定水中微囊藻毒素-LR

建立了全自动化在线固相萃取-二维高效液相色谱-串联质谱法测定水中微囊藻毒素-LR的新方法。一维液相系统（上样泵）直接将100μL水样泵送入固相萃取柱富集,六通阀自动切换,另一维液相系统（分析泵）则将微囊藻毒素-LR冲洗至分析柱进行分离检测。试验结果表明,该方法快速、灵敏度高、精密度好。能够满足生活饮用水及其水源水中痕量微囊藻毒素-LR的检测要求,也非常适合突发水质污染时的应急检测。饮用水和水源水中高低两种浓度微囊藻毒素-LR的平均加标回收率分别为99．1％～106．0％和108．4％～108．8％,相对标准偏差为2．4％～7．0％和1．8％～9．4％,微囊藻毒素-LR的检出限为0．0026μg／L远低于国标0．06μg／L的检出限。     

LC-MS/MS测定南美白对虾中乙氧基喹啉残留

建立了高效液相色谱法-串联质谱法检测南美白对虾中乙氧基喹啉残留的方法。正己烷提取目标分析物,采用C18色谱柱进行分离、质谱进行分析,步骤简单方便。本方法针对南美白对虾肌肉组织的检测下限为5μg/kg,线性范围:5～50μg/kg。3水平添加回收率为80%～90%,相对标准偏差0.53%～2.19%。     

Bestimmung von Spurenverunreinigungen in Tantalpentoxid mit ICP-Atomemissionsspektrometrie (ICP-AES) und ICP-Massenspektrometrie (ICP-MS) nach multielementfähigen Spuren-Matrix-Trennungen

Determination of Trace Impurities in Tantalum Pentoxide by ICP-AES and ICP-MS after Trace-Matrix-Separation A trace–matrix separation procedure based on anion exchange is presented. 500 mg Ta₂O₅ are dissolved in hydrofluoric acid in a Teflon bomb. Ta is retained on the resin column in the form of different fluoro complexes. Most analytes pass the column as cations. Others, like Ti, Zr, Hf, V, Nb also form fluoro complexes. Based on a thorough investigation of the complex equilibria two selective elution procedures using 1M HCl or 0.5M HNO₃ + 0.5M HF are developed. Both methods require a minimum of equipment and reagents, thus drastically reducing the risk of contaminations. The separation procedures are suitable for on-line coupling with both ICP spectrometric techniques. More than 30 analytes can be determined including Ti, Zr, Hf, V, Nb, Mo, and W. Taking an aliquot of 100 mg Ta₂O₅ detection limits are less than 1 μg for ICP-AES or 10 ng for ICP-MS for most elements. For example, 1.3 ng of Nb can be detected in 100 mg Ta₂O₅ by ICP-MS after separation from the matrix.