高效液相色谱柱前衍生化法测定牛磺酸含量

高效液相色谱柱前衍生化法测定牛磺酸含量谢继红,陈玉仁,唐少珍（大连市医药科学研究所大连ｌ１６０１３）１前言牛磺酸又称牛胆硷（Ｔａｕｒｉｎｅ）,其化学名为２－氨基乙磺酸,普遍存在于动物体内,特别是海洋生物体内,据文献报道￣［１－３］,牛磺酸以游离形式存...     

Determination of free amino acids by precolumn derivatization with phenylisothiocyanate. Application to wine samples

Summary A method to determine free amino acids by pre-column derivatization with phenylisothiocyanate is discussed. The method has been applied to determine free amino acids in wine samples, and the results have been compared with those obtained by means of an automatic orthophthal-aldehyde-9-fluorenylmethyloroformate (OPA-FMOC) method.     

苯基异硫氰酸酯衍生氨基酸的高效液相色谱分析

苯基异硫氰酸酯衍生氨基酸的高效液相色谱分析杨扬,秦强,郭伟忠（江苏石油化工学院应化系常州２１３０１６）１前言采用苯基异硫氰酸酯（ＰＩＴＣ）衍生氨基酸并用高效液相色谱测定的报道国外较多￣［１－４］。该法的优点是ＰＩＴＣ与氨基酸、亚氨基酸都能反应生成ＰＴ...     

Oxidation of acetophenone in a high temperature open-tubular capillary column liquid chromatographic system

Summary Acetophnone, a substance stable at room temperature, is readily oxidizes in a high temperature open tubular liquid chromatographic system by the residual oxygen in the mobile phase. The oxidation product is less UV absorptive and detection sensitivity decreases greatly. To prevent the oxidation, through degassing of the mobile phase is necessary.     

High performance liquid chromatography of disaccharides on a porous graphitic carbon column applying post-column derivatization with benzamidine

Summary A sensitive post-column fluoresence method based on the reaction of reducing sugars with a fluorigenic reagent (benzamidine) under alkaline conditions and elevated temperature is described. Optimum reaction conditions suitable for the detection of fluorescent reaction products have been investigated. A porous graphitized carbon column (shandon Hypercarb) was employed as the chromatographic solid phase and elution was isocratic by an aqueous acetonitrile mixture.A special problem in sugar analysis is the tendendy of anomer formation giving doublet peaks. This tendency varies largely among the different sugars, and systematic studies on conditions that eliminate this problem were performed. Efficient and selective separations of a series of disaccharides were obtained using high temperatures and a low concentration of acetonitrile in the mobile phase. The detection limits (S/N=3) with an injection volume of 20 L ranged from 10–60 picomoles. Linear calibration graphs were obtained in the 2–20 M concentration range (r ²>0.99). A relative standard deviation between 1–3% (n=6) demonstrated good precision of the developed system.Deceased July 21, 1996     

Determination of paracetamol (acetaminophen) by HPLC with post-column enzymatic derivatization and fluorescence detection

Summary A novel method is described for the determination of paracetamol (acetaminophen;N-acetyl-4-aminophenol) in urine. After reversed-phase HPLC separation, paracetamol is oxidized by H₂O₂ with horseradish peroxidase catalysis. Detection is performed fluorimetrically at an excitation wavelength of 329 nm and an emission wavelength of 435 nm. Urine samples were spiked with paracetamol, diluted, and injected directly without further pretreatment. Under these conditions, the limit of detection was 2×10⁻⁸ molL⁻¹, and the limit of quantification was 7×10⁻⁸ molL⁻¹. The method was validated by two different approaches based on HPLC with UV-Vis detection.     

Quantitative evaluation of amino acids using microwave accelerated hydrolysis

Summary An improved method for the quantitative determination of amino acids using HPLC, after preliminary derivatisation with o-phthalaldehyde, is described. Separation was carried out on a LiChrospher RP-18 column, using gradient elution and a fluorescence detector. Hydrolysis was performed with 6M HCl or with 3M p-toluenesulphonic acid depending on the amount of carbohydrates in the sample. In addition, the time required for total hydrolysis was shortened from 24 hours to 15 minutes by the use of a microwave oven. The results with these two hydrolytic methods are compared with regard to the extent of peptide bond cleavage and the percentage of decomposition of amino acids in a test mixture.     

L-N-(3,5-Dimethoxybenzoyl)isoleucine chiral stationary phase for separation of enantiomers by HPLC

Summary L-N-(3,5-dimethoxyoxybenzoyl)isoleucine, ionically bonded to γ-aminopropyl silica, has been tested as a chiral stationary phase for the separation of racemates by HPLC. The phase shows good selectivity towards different types of racemates and in particular for those having an electron-poor aromatic group in their molecule. The separation of benzoin racemate can be achieved on the developed chiral phase with an α value of 1.10.     

手性柱前衍生高效液相色谱法拆分牙本质中天冬氨酸对映体

手性柱前衍生高效液相色谱法拆分牙本质中天冬氨酸对映体傅世江,范垂昌,张世鑫魏奉群赵婷（中国医科大学法医化学教研室沈阳１１０００１）（辽宁基础医学研究所沈阳ｌ１０００３）（辽宁省分析测试研究中心沈阳１１００１５ｊ１前言由于氨基酸消旋化理论￣［１］在考古...     

Enantiomeric separation of unusual secondary aromatic amino acids

Summary High-performance liquid chromatographic and gas chromatographic methods were developed for the separation of unusual secondary aromatic amino acids. Amino acids containing 1,2,3,4-tetrahydroisoquinoline, 1,2,3,4-tetrahydronorharmane-1-carboxylic acid and 1,2,3,4-tetrahydro-3-carboxy-2-carboline moieties were synthetized in racemic or chiral forms. The high-performance liquid chromatography was carried out either on a teicoplanin-containing chiral stationary phase or on an achiral C₁₈ column. In the latter case the diastereomers of the amino acids formed by precolumn derivatization with the chiral reagents 2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyl isothiocyanate or 1-fluoro-2,4-dinitrophenyl-5-L-alanine amide were separated. The gas chromatographic analyses were based on separation on a Chirasil-L-Val column. Presented at: Balaton Symposium on High-Performance Separation Methods, Siófok, Hungary, September 3–5, 1997     

Amino acid analysis by derivatization with chromogenic 4-phenylazobenzyloxycarbonyl chloride (PAZ-Cl): Comparison of reversed-phases

Summary The chromogenic reagent 4-phenylazobenzyloxycarbonyl chloride (PAZ-Cl) was used for the automated pre-column derivatization of amino acids (AAs) at ambient temperature followed by liquid chromatographic separation of the derivatives formed.Since in previous investigations it was realised that the selectivity of a C-18 stationary phase decreased after 40 injections of PAZ-AAs the suitability of 12 reversedphases distinguished by silica modification, carbon content, and particle characteristics was tested. Among these columns only a polymer-coated C-18 stationary phase furnished satisfactory repeatability of retention times for 250 analyses.     

柱前衍生高效液相色谱法测定减肥药中的芬氟拉明

建立了柱前衍生反相高效液相色谱—紫外检测方法用于测定减肥药中的芬氟拉明。样品用三氯甲烷萃取,异丙醇转溶,再在四氢呋喃中和60℃下,用苯异氰酸酯衍生35min,然后用甲醇／水(72／28,V／V)为流动相和Kromasil C18分离柱,在240nm检测衍生物。方法的线性范围在2．52—126mg／L(r=0．9994),检出限和定量限分别为0．36ng(S／N=3)和1．2ng(S／N=10),平均回收率为98．4％,相对标准偏差(RSD)小于3．00％。     

2-Bromoacetyl-6-methoxynaphthalene: A useful fluorescent labelling reagent for HPLC analysis of carboxylic acids

Summary The use of 2-bromoacetyl-6-methoxynaphthalene as a fluorogenic labelling reagent in pre-column derivatization for the HPLC separation of biologically active carboxylic acids (fatty acids and bile acids) has been investigated. The compound reacts (30 min. at 70°C) with carboxylic acids to give fluorescent esters that can be separated by reversedphase HPLC and detected at ex. 300 nm, em. 460 nm. The experimental conditions for the derivatization and chromatographic separation are discussed. Applications to the determination of valproic acid and chenodeoxycholic acid in pharmaceutical formulations are described.     

Fully automated high-performance liquid chromatographic separation of DL-amino acids derivatized witho-phthaldialdehyde together withN-isobutyryl-cysteine. Application to food samples

Summary A method is presented that enables the fully automated precolumn derivatization of mixtures of DL-amino acids (DL-AA) witho-phthaldialdehyde together withN-isobutyryl-L(orD)-cysteine. HPLC on a 250 mm×4 mm i.d. column packed with Shandon Hypersil ODS, 5 μm, and a linear gradient formed from 23 mM sodium acetate (pH 6.0) and methanol/acetonitrile (600 ml+50 ml) separates completely an AA standard composed of 17 pairs of DL-AA (including Asn and Gln), Gly and the internal standard L-homo-Arg, within 75 min at a flow rate at 1 ml/min. Applications are shown of the determination of free D-AA isolated from an orange juice concentrate and from soy sauce, and the detection of D-AA in a gelatine total hydrolysate. In the case of these foodstuffs fluorescence detection (excitation at 230 nm, emission at 445 nm) allows the routine detection of 5–10 pmol per AA; and approx. 0.2–1% D-AA, in an excess of L-AA, are quantifiable. Presented in part at the “International Symposium on Separation of Peptides, Proteins and Polynucleotides”, October 29–31, 1990, Wiesbaden (abstract 620), ANAKON '91, April 22–24, Baden-Baden (abstract C 5), and at the “15th International Symposium on Column Liquid Chromatography”, June 3–7, 1991, Basel (abstract P26/2).     

Microwave-assisted water extraction of acid herbicides from soils coupled to continuous filtration, pre-concentration, chromatographic separation and UV detection

A microwave-assisted extraction procedure using water as extractant has been performed for the extraction of acid herbicides (namely, bentazone, 2,4-D, trichlopyr, 2,4,5-T and 2,4,5-Tp) from different types of soil. Two experimental designs were used for the optimization of the leaching step. The selection of water as extractant provided a clean approach by avoiding the use of organic solvents. The use of water also enhanced the extraction efficiency due to the high interaction of the microwave irradiation with polar solvents. The time required for total removal of the target compounds was 35 min. The recoveries yield were from 87.64 to 106.14% with a repeatability (expressed as relative standard deviation) ranging between 1.34 and 9.24%. A within-laboratory reproducibility, also expressed as relative standard deviation, varied from 3.97 to 10.41%. A flow-injection manifold allowed automation of the whole process by hyphenating the steps subsequent to extraction (namely, filtration, preconcentration, chromatographic separation and UV detection) for the determination of the analytes.     

Simultaneous separation and identification of hashish constituents by coupled liquid chromatography-mass spectrometry (HPLC-MS)

Summary This paper reports the use of liquid chromatography for the separation and determination of the major cannabinoids extracted from hashish samples. The direct coupling to the mass spectrometer enables the selective identification both of neutral and acidic cannabinoids. The developed method does not require any preliminary derivatization and should, therefore, be of interest in forensic analysis for simple and unequivocal determination of hashish constituents.Part of this work was presented at the 2nd Italian-Spanish Joint Meeting of Medicinal Chemistry, 30 August–3 September 1995, Ferrara, Italy.     

Modified polystyrene,stationary phases for the separation of different aromatic hydrocarbon types by HPLC

Summary One possible method of characterizing chemicall-modified stationary phases is to describe their chromatographic properties. In this study we investigated several chemically-modifiedpolystyrene-divinylbenzene packings for the separation of nitroarenes, polycyclic aromatic hydrocarbons and aminosubstituted aromatic hydrocarbons. Chromatography was carried out on commercially available polymer stationary phases, for example C-18 or vinylpyridine modified polystyrene. In addition, a chemically-immobilized polymer packing was prepared by introducing nitrogroups, which were established by elemental analysis and infrared spectroscopy.     

Optimization of St John's Wort flavonoid separation by reversed phase liquid chromatography on a silica-based monolithic column

Summary An optimization procedure for the separation of flavonoids from St John's Wort by reversed-phase high-performance liquid chromatography on monolithic stationary phase is described. Three-component mobile phase systems are studied using experimental design methodology. The starting experimental domain is a triangle, each vertex of which is a pure component. From preliminary isocratic experiments, truncations in the domain are performed leading to a quadrilateral shape working domain with no symmetry. To cope with both separation and analysis time, desirability functions are used. Optimal conditions are finally given by binary systems and the four flavonoids are separated in less than seven minutes.     

Automated high-performance liquid chromatographic determination of amphetamine in biological fluids using column-switching and on-column derivatization

Summary A rapid and simple liquid-chromatographic method has been developed for on-line quantification of amphetamine in biological fluids. Untreated samples (20 μL) are injected directly into the chromatographic system and purified on a 20 mm×2.1 mm i.d. pre-column packed with 30 μm Hypersil C₁₈ stationary phase. After clean-up the analyte is transferred to the analytical column (125 mm×4 mm i.d., 5 μm LiChrospher 100 RP₁₈) for derivatization and separation using a mixture of acetonitrile and the derivatization reagent (o-phthaldialdehyde andN-acetyl-L-cysteine) as the mobile phase. The experimental conditions for on-line derivatization and resolution of the amphetamine have been optimized, and the results have been compared with those obtained by derivatizing the analyte in pre-column mode. The method described has been applied to the determination of amphetamine in plasma and urine. Good linearity and reproducibility were obtained in the 0.1–10.0 μg mL⁻¹ concentration range, and limits of detection were 25 ng mL⁻¹ and 10 ng mL⁻¹ with UV and fluorescence detection, respectively. The procedure described is very simple and rapid, because no off-line manipulation of the sample is required; the total analysis time is approximately 8 min.     

High-performance-liquid chromatographic separation of 1,3,5-trizine herbicides

Summary A number of 11 triazine herbicides and 7 of their corresponding metabolites were separated in a single HPLC run. The separation was achieved on a reversed-phase column using gradient elution with acetonitrile/buffer. Detection was by UV absorption at a wave-length of 220 nm.