Analysis of Monosaccharide Composition of Pu-erh Tea Polysaccaride by Pre-column Derivatization HPLC

[Objective] This study aimed to establish a pre-column derivatization HPLC method for the identification and analysis of monosaccharide composition of Pu-erh tea polysaccharide. [Method] Pu-erh tea polysaccharide was extracted using the wa- ter extraction method, further isolated and purified by DEAE cellulose-52 columns. The obtained tea polysaccharide and four components TPS1, TPS2, TPS3 and TPS, were first derived by 1-phenyl-3-methyl-5-pyrazolone （PMP）, and then the PMP derivatives of monosaccharide were analyzed by high performance liquid chromatog- raphy （HPLC）. [Result] Pu-erh tea polysaccharide contained eight kinds of monosac- chaddes （mannose, rhamnose, glucuronic acid, galacturonic acid, grucose, galactose, arabinose, fucose）, without xylose; so it was the same with TPS1; each of TPS2, TPS3 and TPS4 contained seven monosaccharides, while no fucose. [Conclusion] This method is simplified and rapid, which can be used to determine the monosac- charide composition of Pu-erh tea polysaccharide and monosaccharide content.

Determination of Sparfloxacin in Human Urine by Reversed-Phase High Performance Liquid Chromatography With Nitrous Acid and Hydroiodic Pre-Column Derivatization

Sparfloxacin can be oxidized by nitrous acid, then react with hydroiodic acid to form a fluorescent derivative. Based on this, a reversed-phase high performance liquid chromatographic pre-column derivatization new method is described for the determination of sparfloxacin in human urine. The linear range is 0.05 mg/L to 4.0 mg/L, the recoveries are 91.5%similar to 95.7% and the RSD is 1.2%similar to4.2%. The results showed that this method is suitable for the determination of sparfloxacin in human urine.

Determination of 18 Kinds of Amino Acids in Fresh Tea Leaves by HPLC Coupled with Pre-column Derivatization

A rapid and accurate quantitative method of high performance liquid chromatography( HPLC) with fluorescence detector has been developed for the analysis of 18 kinds of amino acids in fresh tea leaves. The samples were minced and mixed,and extracted with ultra pure water at 90℃ for 20 min. The 6-aminoquinolyl N-hydroxy-succinimidyl carbamate( AQC) was used as pre-column derivatization reagent. Gradient HPLC separation was performed on a C_(18) column( Symmetry C_(18),3. 9 mm × 15 cm,4 μm). Good linearity between concentrations and peak areas was achieved in the concentration range of 5. 0-250 μmol/L for 18 kinds of amino acids. The method was validated by the analysis of five replicates. The 18 kinds of amino acid standards were spiked in fresh tea leaf samples and the average recovery rate was 86. 25%-109. 05% with relative standard deviations( n = 5) ranging from 6. 03% to 10. 56%. The limit of detection( LOD) for the analytes was0. 05-1. 27 μmol/L. The method was successfully applied to the analysis of the 18 kinds of amino acids in fresh tea leaves from east Dongting and west Dongting mountains in Suzhou. The results indicate that the method is simple,rapid,precise and reliable.

Preparative Resolution of Gatifloxacin Enantiomers with Pre-Column Esterification Strategy and Comparing Their Enantioselectivity to Bacteria and Antibody

Gatifloxacin （GFX） is a kind of chiral fluoroquinolones compound due to the methyl group at the C-3 position of the piperazine ring[1]. Although the enantiomers of GFX show similar levels of antimicrobial activity and pharmacokinetics[2], the other biological activities （i.e., toxicity or enantioselective recognition to various receptors in vivo） of GFX enantiomers have not yet been studied. With this in mind, we developed a rapid and cost-effective high performance liquid chromatographic （HPLC） separation procedure for GFX enantiomers with a pre-column esterification strategy.

Enantioresolution of a Series of Chiral Benzyl Alcohols by HPLC on a Dinitrobenzoylphenylglycine Stationary Phase after Achiral Pre-Column Derivatization

High performance liquid chromatography method for the separation of a series of chiral benzyl alcohols on N-(3,5-dinitrobenzoyl)-D-phenylglycine stationary phase (Macherey Nagel, Chiral-2) after pre-column achiral derivatization was developed. Cheap and easy available aromatic acid chlorides were used as derivatization agents. Good to excellent separations of the enantiomers were achieved in all cases in relatively short analytical runs. It was shown that the enantiorecognition depends on the substituents both in the starting alcohol and in the acid chloride. The method presents an efficient alternative to the direct analyses on polysaccharide and cyclodextrine-derived stationary phases.

Pre-column Derivatization-High Performance Liquid Chromatography for the Detection of Monensin in Livestock and Poultry Meat

[Objectives]A method for the detection of monensin in poultry and livestock meat by pre-column derivatization-high performance liquid chromatography was established.[Methods]The sample was extracted with chloroform,derivatized with trichloroacetic acid and 2,4-dinitrophenylhydrazine,and centrifuged to obtain a purified solution.A C18 chromatographic column(4.6 mm×150 mm,5μm)was used for separation with(1.5%)acetic acid water∶methanol(volume ratio)=1∶9 as the mobile phase using a DAD detector for detection,and the external standard method was adopted for peak area quantification.[Results]Monensin had good linearity in the concentration range of 5.00-200 mg/L,with the linear correlation coefficient r 2>0.999;the detection limit was 5.00 mg/kg;the relative standard deviation was smaller than 10%;and the recoveries of standard addition experiment were in the range of 75%-110%.[Conclusions]The method has the advantages of simple pretreatment operation,good derivatization effect and fast detection speed,and is suitable for detecting monensin in poultry and livestock meat.

Coupling of on-Line Pre-Column Oxidative Cleavage and Solid-Phase Enrichment with Liquid Chromatography Using an Eco-Friendly Analytical Procedure to Determine Low Levels of Methotrexate

A simple, sensitive and precise green high-performance liquid chromatographic method including on-line pre-column oxidation combined by column switching with a short Hypersil ODS analytical column (100 mm × 4.0 mm i.d.) for enrichment and separation was developed and validated to determine low levels of methotrexate (MTX). The method was based on oxidative cleavage of MTX into highly fluorescence products, 2,4-diaminopteridine-6-carboxaldehyde and the corresponding 2,4-diaminopteridine-6-carboxylic acid, during the flow of phosphate buffer (0.04 M, pH 3.4) containing the analyte through the packed reactor of cerium (IV) trihydroxyhydroperoxide (CTH) at a flow-rate of 0.2 mL/min and 40℃. The fluorescent products were enriched on the head of ODS analytical column for the final separation. The separation was performed at room temperature using an environmentally friendly mobile phase consisting of ethanol and phosphate buffer (0.04 M, pH 3.4) in the ratio of 10:90 (v/v). The eluent was monitored at emission and excitation wavelengths of 463 and 367 nm, respectively. The method was successfully applied, without any interference from the excipients, for the determination of drug in tablets and vials with a detection limit of 0.06 ng/mL from 500 ?L of sample MTX.

HPLC of Amino Acids and Oligopeptides by Pre-Column Fluorescence Derivatization with 9-Acridine Formyl Chloride

A highly sensitive HPLC method for the detection of amino acids and oligopeptides with 9-acridine formyl chloride by pre-column fluorescence derivatization has been developed. Glycine, glycylglycine, histidine, triglycine and glutathione were separated on a reversed-phase C-18 column with methanol-water-triethylamine eluent, derivatization and chromatographic conditions were optimized. The five derivatives were eluted in 28 min with a good reproducibility. Linear range of the calibration graph was 0.08-260 nmol/ml(-1). The relative standard deviations(n=6) are < 5%. Detection limits (signal-to-noise ratio=3) for the five derivatives are 20-40 fmol.

鸡组织中链霉素残留检测方法的研究

采用柱前衍生化、紫外检测器高效液相色谱法(HPLC)检测鸡组织中链霉素的残留量,优化了样品的前处理方法和高效液相色谱条件(包括流动相的组成和流速),同时优化了前处理过程中洗脱液和提取液的用量。结果表明:流动相为V(乙腈)∶V(醋酸盐缓冲液pH=3 3)∶V(水)=10∶10∶80,流速0 3mL min,柱温35℃,检测波长252nm,进样量20μL为最佳检测条件。采用沉淀剂(5%5mL三氯醋酸)沉淀蛋白质,洗脱剂(10mL甲醇)洗脱,在3种不同鸡组织中添加200,100,50μg mL3种标准溶液,测定其回收率分别为75%～90%,70%～86%,64%～75%,变异系数均≤10%。同一试样设10个平行样,其变异系数为5 72%,说明该方法的重现性较好。

超高效液相色谱法快速检测粮食中黄曲霉毒素的含量

建立了免疫亲和柱净化-超高效液相色谱法快速测定粮食中黄曲霉毒素(Aflatoxins,AF)的检测方法。样品经提取后,用免疫亲和柱净化、浓缩,Waters Acquity UPLC BEH C18色谱柱(50 mm×2.1 mm,1.7!m)分离。以甲醇-水(40∶60,V/V)为流动相,流速为0.2 mL/min,进样量为1!L,荧光检测器检测,激发波长为360 nm,发射波长为440 nm,无需衍生。黄曲霉毒素B1,B2,G1,G2的保留时间小于5 min,从样品前处理到结果分析整个过程小于45 min。根据3倍信噪比的峰响应值,确定黄曲霉毒素(B1,B2,G1,G2)检出限分别为0.15,0.05,0.40,0.06 pg,4种毒素在0.4～60.0 pg,0.2～15.0 pg,1.5～60.0 pg和0.2～15.0 pg范围内分别呈线性相关,相关系数R2值分别为0.9999,0.9999,0.9998和0.9992;在小麦、玉米、稻谷3类样品中加标回收率为77.4%～104.2%,精密度为1.8%～8.9%。本方法无需衍生即可同时测定粮食中4种黄曲霉毒素,适用于粮食中黄曲霉毒素的快速定量测定。

丹磺酰氯作为氨基酸柱前衍生试剂衍生条件的研究

用丹磺酰氯为柱前衍生试剂，对１９种氨基酸的衍生物进行了高效液相色谱分离．研究了衍生试剂的用量、缓冲体系的ｐＨ值、衍生时间等条件的变化对衍生反应的影响，得到了用丹磺酰氯对氨基酸的最佳衍生条件．

小肽不同高效液相色谱柱前衍生化反应的实验研究

分别用氯甲酸-9-芴基甲酯（9-fluorenylmethylchloroformate，FMOCCl）、9-芴基甲氧基甲酸琥珀酰亚胺类酯（9-fluorenylmethoxy carbonyl succinimide，FMOC-OSU）和丹磺酰氯（1-dimethylaminonaphthalene-5-sulfonyl-chloride，Dns-Cl）为衍生化试剂对小肽进行了衍生化反应.研究和比较了各种衍生试剂用量、衍生缓冲体系pH条件、衍生化时间等因素对衍生反应的影响及衍生产物的稳定性.结果发现，FMOC-Cl对肽的衍生反应速度快，衍生反应完全，衍生产物稳定.

莫能菌素和盐霉素在鸡组织中的残留分析方法研究

本文报道用高效液相色谱柱后衍生化检测肉鸡肌肉、肝脏和脂肪组织中莫能菌素和盐霉素的残留。肉鸡肌肉、肝脏和脂肪组织经异辛烷提取 ,用硅胶柱净化分离 ,洗脱液浓缩后用甲醇 /水溶解。以甲醇 /冰乙酸 /水 ( 94 0 / 30 / 30 ,v/v)作为流动相 ,香草醛为衍生剂 ,用RP C18柱在可见波长52 0nm处检测。将莫能菌素和盐霉素分别以 0 10 ,0 2 0 ,0 4 0和 0 2 0 ,0 4 0 ,0 80 μg/ g分别添加到空白肉鸡组织中 ,测得莫能菌素和盐霉素在肌肉、肝脏和脂肪组织中的平均回收率分别为 97 7%、91 1%、92 1%和 94 1%、85 4 %、90 7% ,变异系数范围在 2 7%～ 16 8%之间。用该方法测定肉鸡组织中莫能菌素和盐霉素残留的最低检测限分别为 0 0 5μg/ g和 0 1μg/ g。

离子色谱柱后衍生法测定汞、锰、镉、钴、锌、镍和铜

提出了用离子色谱柱后衍生法同时测定汞和其它金属离子的新方法。本方法中样 品离子以阴离子交换分离，用２－（５－溴－２－吡啶偶氮）－５－二乙氨基酚（５－Ｂｒ－ＰＡＤＡＰ）和非离子 表面活性剂 Ｔｒｉｔｏｎ Ｘ－１００显色体系作柱后衍生，分光光度法测定。方法的检出限对 Ｈｇ２＋、 Ｍｎ２＋、Ｃｄ２＋、Ｃｏ２＋、Ｚｎ２＋、Ｎｉ２＋和Ｃｕ２＋分别为２０、９、９、８、２、１００和 ３ μｇ／Ｌ。方法用于人头发样 品中微量汞的分析取得了满意结果。

柱前衍生高效液相色谱法测定白菜及小麦中草甘膦残留量

运用荧光衍生试剂FMOC-Cl衍生草甘膦后,利用双聚合氨基柱HPLC测定了白菜及小麦中草甘膦的含量,该方法灵敏度高,可靠性强。通过试验,找到了最佳衍生条件和色谱条件。该方法通过测定蔬菜及小麦样品得到了确证,在添加草甘膦标样1mg/kg时,最低检出限为0.3mg/kg,平均回收率为82.4%,变异系数为10.3%。

固相微萃取-气相色谱法测定水中的甲基膦酸

报道了应用固相微萃取 -气相色谱法测定水中甲基磷酸的方法 ,研究了不同固相微萃取纤维、萃取温度和时间、解吸时间、pH值等萃取条件和衍生化温度和时间、衍生化程序等衍生条件对测定效果的影响 ;结果表明该法简便、快速、有效 ,其检出限为0.03mg/L。

气相色谱质谱联用负化学源法检测方便面调料包中的氯丙醇

目的：建立高灵敏度低基体干扰的分析方法用于检测方便面调料包中的氯丙醇。方法：以气质联用负化学源法（Gc-Ms-NCI）同时分离检测方便面调料包中的3-氯-1，2-丙二醇（3-Monochloropropane-1，2-diol，简称3-MCPD）和1，3-二氯-2-丙醇（1，3-Dichloro-2-propanol，简称1，3-DCP）。经稳定性同位素（d5-3-MCPD和d5-1，3-DCP）稀释后的样品，通过Extrelut^TM 20填料分散萃取，三乙胺催化的七氟丁酸酐（HFBA—Et3N）衍生后，GC-Ms—NCI法测定。结果：各氯丙醇检出限均为1．0μg／kg，在进样浓度为0．001—1μg／ml的范围内线性良好。结论：由检测数据来看，市售方便面中氯丙醇的污染不容乐观。

高效液相色谱与化学计量学方法联用测定多种氨基酸对映体

用邻苯二甲醛和N_乙酰_L半胱氨酸作为柱前手性衍生化试剂,使用常规反相高效液相色谱法拆分DL_氨基酸对映体,对于不能达到基线分离的色谱峰,应用化学计量学方法计算分析,从而达到同时定量测定多种氨基酸对映体的目的.

草甘瞵含量液相色谱检测衍生化条件的优化筛选

对液相色谱测定水体及水葫芦中草甘膦含量的对甲基苯磺酰氯衍生化反应条件进行了优化筛选,得出最佳衍生化条件为反应缓冲液pH10．5-11．0、盐浓度0．4 mol／L,对甲苯磺酰氯与草甘膦质量比大于7．5: 1,于50℃水浴中反应30 min。

酪氨酸与CGE（N）的反应及其在荧光检测中的应用

本实验建立了以自制新荧光剂ＣＥＧ（Ｎ）为衍生化试剂测定氨基药物（或化合物）的方法。以酪氨酸为试验化合物与ＣＧＥ（Ｎ）在碱性条件下发生反应。产品经四谱及元素分析证明与预期结构一致。又借助此反应，用薄层荧光扫描法检测酪氨酸，测定结果：酪氨酸－ＣＧＥ（Ｎ）的ＥＸ＝２７７ｎｍ，ＥＭ＝３６６ｎｍ；定量线性范围在０．５～１５μｇ，检测限０．５μｇ（以酪氨酸计），线性回归相关系数在０．９９以上，稳定时间为２５小时。结果表明了新型荧光剂的可用性及方法的可靠性。