Determination of Plant Thiols by Liquid Chromatography Coupled with Coulometric and Amperometric Detection in Lettuce Treated by Lead(II) Ions

The main aim of this paper is to utilize high performance liquid chromatography with electrochemical detection for determination of thiols content in plants tissues of lettuce treated with lead(II) ions (0, 0.5 and 1 mM). We used two HPLC‐ED instruments: HPLC coupled with one channel amperometric detector and HPLC coupled with twelve channel coulometric detector to detect simultaneously twelve thiols. The detection limits of thiols measured by CoulArray detector were about two magnitudes lower in comparison to those measured by Coulochem III detector and were from tens to hundreds pM. Under the optimal conditions, we utilized HPLC‐CoulArray detector for analysis of tissues from lettuce plants. In addition, distribution and accumulation of lead ions with high spatial resolution was monitored using laser induced breakdown spectroscopy.     

局部麻醉药的反相色谱安培法检测

本文系统研究了普鲁卡因,利多卡因,丁卡因等3种局部麻醉药的液相色谱安培法检测行法,并与液相色谱光度法检测结果进行了比较。     

液相色谱中的安培检测

介绍了液相色谱中直流安培、脉冲安培和积分安培检测的基本原理及使用条件和范围。     

液相色谱-脉冲安培电化学法测定硫酸卡那霉素中各组分含量

建立了一种用反相离子对液相色谱(LC)分离,以金电极为工作电极的脉冲安培电化学法(PAD)直接检测硫酸卡那霉素中主要组分及杂质含量的分析方法。流动相为0.033mol/L草酸、0.012mol/L七氟丁酸、105mL/L乙腈,用稀NaOH调节pH至3.4。考察了各色谱参数对分离测定的影响。实验证明,本方法不需要衍生化,可直接检测硫酸卡那霉素。与报道的其它方法相比,本方法不仅能使硫酸卡那霉素中的卡那霉素A、B得到了很好的分离,还分离出了其它一些未能确证的组分。如用质谱法等对未知组分进行确证后,对硫酸卡那霉素原料药、注射液、滴眼液及兽药等实际样品中的卡那霉素各组分进行测定。可望成为一种标准分析方法。     

Liquid Chromatography with Pulsed Amperometric Detection for Speciation of Mercury

Liquid chromatography with pulsed amperometric detection (PAD) at an Au electrode was successfully applied for speciation of mercury: inorganic mercury, methylmercury and ethylmercury. The optimized conditions for triple-step potential waveforms utilized in PAD were: E₁ 1800 mV, t₁ 50 ms; E₂ 300 mV, t₂ 3850 ms; E₃ 750 mV, t₃ 100 ms; mercury oxidation was monitored at E₃. With the eluent of HClO₄ (0.10 M) + KCl (1.0 mM) + CH₃CN (1.0%) at a flow rate 0.80 mL/min, three mercury species were fully separated in 6 min on a glass column (3 mm × 10 cm) packed with Chemcosorb C₁₈ (5 μm). However, the first peak (inorganic mercury) was commonly overlapped by the solvent front. The relative standard deviations (n = 6) for methylmercury (15 ppb) and ethylmercury (30 ppb) were 4.2% and 2.8%, respectively. The linear range tested was 2 – 500 ppb (r = 0.9998) for methylmercury, and was 4 – 1000 ppb (r = 1.000) for ethylmercury. The detection limits (S/N = 3) were 1.2 ppb and 1.8 ppb for methylmercury and ethylmercury, respectively. The results of determination of the mercury-containing species thimerosat in three commercial contact-lens solutions agreed satisfactorily with the expected values.     

反相高效液相色谱分离-安培法检测酚类化合物

本文报道了RP-HPLC-安培法检测测定酚类化合物的条件。在Shim-pack CLC-C_8柱上用含0.05mol/L NaH_2PO_4缓冲溶液的5％甲醇水溶液洗脱分离,于E+1.0V处检测。线性范围在0～7μg/ml,检测限达ng/ml。     

Commercial Screen‐Printed Gold Electrodes for the Detection and Quantification of Aminothiols in Human Plasma by Liquid Chromatography with Electrochemical Detection

In order to show the possibilities of screen‐printed electrodes in HPLC detection, a method is presented for routine quantification of aminothiols in human plasma. It uses commercial gold screen‐printed electrodes and provides a rapid, simple and economical procedure with a disposable detector and without any additional electrode. By working at 98 : 2 (0.05 % trifluoroacetic acid: methanol) and 0.9 V, it allows us to determine cysteine (Cys), cysteinyl‐glycine (Cys‐Gly), and homocysteine (HCys) at μmol/L levels. The method was validated, and linearity range, detection and quantification limits, precision and accuracy were evaluated by external calibration and by using N‐acetylcysteine as internal standard, which exhibited better precision.     

反相离子对色谱-脉冲安培电化学法测定硫酸庆大霉素中各组分含量

建立了一种新的用反相离子对液相色谱(LC)分离,以金电极为工作电极的脉冲安培电化学法(PAD)直接检测硫酸庆大霉素中各组分含量的分析方法。流动相为0.033 mol/L草酸、0.012 mol/L七氟丁酸、210 mL/L乙睛,用稀NaOH调节pH至3.4。与报道的其它方法相比,该方法能使庆大霉素各有效组分C1、C1 a、C2、C2 a很好分离,整个分析过程<30 m in。考察了各色谱参数对分离测定的影响。实验证明,本方法不需要衍生化,可直接检测硫酸庆大霉素。     

液相色谱电化学检测抗结核药物—异烟肼

本文讨论了以无有机溶剂存在的水溶液为流动相异烟肼的液相色谱一薄层安培检测法。在所选定的实验条件下,检测限达2ng。应用本法分析了片剂中异烟肼的含量     

Determination of Aldehydes and Ketones in Fuel Ethanol by High-Performance Liquid Chromatography with Electrochemical Detection

A new methodology was developed for analysis of aldehydes and ketones in fuel ethanol by high-performance liquid chromatography (HPLC) coupled to electrochemical detection. The electrochemical oxidation of 5-hydroxymethylfurfural, 2-furfuraldehyde, butyraldehyde, acetone and methyl ethyl ketone derivatized with 2,4-dinitrophenylhydrazine (DNPH) at glassy carbon electrode present a well defined wave at +0.94 V; +0.99 V; +1.29 V; +1.15 V and +1.18 V, respectively which are the basis for its determination on electrochemical detector. The carbonyl compounds derivatized were separated by a reverse-phase column under isocratic conditions with a mobile phase containing a binary mixture of methanol / LiClO_4(aq) at a concentration of 1.0 × 10⁻³ mol L⁻¹ (80:20 v/v) and a flow-rate of 1.1mL min⁻¹ . The optimum potential for the electrochemical detection of aldehydes-DNPH and ketones-DNPH was +1.0 V vs. Ag/AgCl. The analytical curve of aldehydes-DNPH and ketones-DNPH presented linearity over the range 5.0 to 400.0 ng mL⁻¹, with detection limits of 1.7 to 2.0 ng mL⁻¹ and quantification limits from 5.0 to 6.2 ng mL⁻¹, using injection volume of 20 μL. The proposed methodology was simple, low time-consuming (15 min/analysis) and presented analytical recovery higher than 95%.     

Rapid and Sensitive Method for Citrinin Determination Using High-Performance Liquid Chromatography with Fluorescence Detection

Citrinin is a toxic product of secondary metabolism of fungi, such as certain Aspergillus, Penicillium, and Monascus species that are usually contaminating cereals. A new sensitive liquid chromatographic method with fluorescence detection was developed, validated, and applied for citrinin determination. The method is based on reversed-phase separation at pH 2.5, where citrinin exhibits the highest fluorescence quantum yield. In this setup, no derivatization step is needed. The method shows linearity in the range between 0.2 μg/mL and 0.1 mg/mL. The detection limit reached is 90 ng/mL (3.6 × 10^?7 M). Validated method was successfully applied on analysis of spiked and real cereal samples.     

液相色谱/多通道电化学检测法在天然酚类化合物测定中的应用

多通道电化学检测是按照新一代电化学检测仪器的要求而设计的产品。它具有使用方便，快速准确，排除干扰等多种功能，非常适用于复杂体系中化合物的测定。本文报道了液相色谱／四通道电化学检测法在天然酚类化合物测定中的应用。此方法能快速获得待测物的流体动力学伏安图(HDV图)；色谱峰的鉴定可靠；在不同电压下同时定量测定不同的化合物。本文以测定蜂蜜中的酚酸类化合物及绿茶中的儿茶素类化合物为例对此分析方法进行了阐述。     

高效液相色谱-脉冲安培检测法测定脑微透析溶液中单胺类神经递质

详细对比了脉冲安培与恒电位安培检测单胺类神经递质的响应值,结果表明冲安培检测上述物质的响应值是恒电位安培检测的1.2倍。建立了以3.4 -二羟基苄胺（DHBA）为内标的定量方法。在微透析溶液中的微量神经递质的回收率在74％－101％之间。     

Determination of Vitamin D3 and 25-Hydroxyvitamin D3 Using Liquid Chromatography with Amperometric Detection

Abstract

The electrochemical behaviour of vitamin D₃ and 25-hydroxyvitamin D₃ (25-OH D₃) in a high performance liquid chromatography system using amperometric detection is described. Separation is carried out using a C18 reversed-phase column and the optimum mobile phase was a 0.1 M LiClO₄ solution in methanol-water (97:3, v/v) at a flow rate of 1.25 ml/min. 25-OH D₃ and vitamin D₃ were eluted with good resolution at retention times of 3 and 6 minutes respectively, and determined by amperometric detection with a glassy carbon electrode at + 1.050 V (vs Ag/AgCl). Calibration graphs for both substances showed good linearity when amounts of vitamin D₃ between 18 and 312 ng and 27 and 412 ng of 25-OH D₃ were injected. Detection limits of 8 ng (vitamin D₃) and 25 ng (25-OH D₃); relative standard deviations of 3.2% (vitamin D₃) and 5.8% (25-OH D₃) were obtained.     

Determination of Synthetic Phenolic Antioxidants in Vegetable Oil and Oil-Enriched Foods by High-Performance Liquid Chromatography with Electrochemical Detection

Three synthetic phenolic antioxidants, tertiary butyl hydroquinone, butylated hydroxytoluene, and butylated hydroxyanisole, were determined in vegetable oil and oil-enriched food by high-performance liquid chromatography (HPLC) with electrochemical detection. The separation was achieved using a reverse-phase column and gradient elution with methanol and 1% acetic acid. The limits of detection and quantification of the analytes were 2–120 lower, higher than those obtained by diode-array detection. The recoveries were 103.3% for tertiary butyl hydroquinone, 97.3% for butylated hydroxyanisole, and 95.2% for butylated hydroxytoluene. The results showed that HPLC with electrochemical detection is suitable for the quantification of low concentrations of phenolic antioxidants in vegetable oil and oil-enriched food with high sensitivity and accuracy.     

酒中甲醇的离子排斥色谱-脉冲安培法测定

建立了离子排斥色谱-脉冲安培法测定酒中甲醇的检测方法。方法使用IonPac ICE-AS6离子排斥柱,以45 mmol/L HClO4为淋洗液,脉冲安培法检测（工作电极为Pt电极）。甲醇的检出限为0.03 mg/L（50μL进样,3倍基线噪音）;在7.9～158 mg/L范围内方法具有良好的线性（r=0.9990）。79 mg/L甲醇标准连续进样9次,峰面积相对标准偏差（RSD）为2.82%。用该方法检测了多种酒样中的甲醇含量,其加标回收率为91%～104%。     

超高效液相色谱-荧光检测法测定人体尿液中酪氨酸、对羟苯基乳酸和对羟苯基乙酸

采用固相萃取技术,结合超高效液相色谱-荧光分析(UPLC-FLD)手段,建立了人体尿液中酪氨酸、对羟苯基乳酸和对羟苯基乙酸的同时测定新方法。系统探讨了不同机理下,应用固相萃取技术处理尿液的效果,最终选用Clean-Screen DAU混合固相萃取小柱处理尿液,成功地除去了大量干扰物质。在优化的实验条件下,上述三种化合物线性关系良好(R20.9996),检测限均为0.016mg/L。健康人和癌症病人尿液三个添加水平的平均回收率在86.9%~107.9%之间,相对标准偏差(RSD)小于2.8%。该方法快速、灵敏度高、选择性好,可用于人体尿液中三组分的同时测定。     

固相萃取-高效液相色谱法测定人体尿液中邻苯二甲酸酯及其代谢物

建立了同时测定人体尿液中邻苯二甲酸酯及其代谢物的分析方法.对洗脱剂种类、洗脱体积、洗脱流速等影响因素进行考察,确定了最佳洗脱剂及洗脱体积为2mL乙腈、2mL乙酸乙酯和1mL乙醚-正己烷(1:19,V/V),洗脱流速1mL/min.在最优化的固相萃取-液相色谱条件下测定5种邻苯二甲酸酯及其5种相应的单酯代谢物,线性范围为...     

阴离子交换-积分脉冲安培检测法分离测定氨基酸注射液中的氨基酸和葡萄糖

 用阴离子交换 积分脉冲安培检测法测定了氨基酸注射液中 1 7种氨基酸和葡萄糖。研究了氨基酸和葡萄糖在阴离子交换中的保留行为。采用了优化的水、NaOH和NaAc三元梯度淋洗条件。在优化的梯度淋洗条件和积分脉冲安培检测条件下 ,氨基酸和葡萄糖的检出限为 0 3pmol～ 1 0 3pmol,线性范围约为 2个数量级。样品加标回收率为 88 3 %～ 1 0 4 6 %。方法简单、灵敏、准确。     

离子色谱中的安培检测方法及其应用

介绍了离子色谱中的安培检测方法(包括恒电位安培检测法、脉冲安培检测法和积分脉冲安培检测法)的原理和应用。脉冲安培检测法与高效阴离子交换色谱结合(HPAEC-PAD)是一种新的分析糖类化合物的方法;积分脉冲安培检测法与高效阴离子交换色谱结合(HPAEC-IPAD)是一种新的氨基酸分析方法。