Determination of Vapor-Phase Carbonyls by High-Pressure Liquid Chromatography

Abstract

Methods have been developed for the trapping and quantitative analysis of low molecular weight carbonyls in complex gas phase mixtures. Formaldehyde, acetaldehyde, acrolein, and acetone are separated as the 2-4-dinitrophenylhydrazones with a sensitivity of less than 10 ppb. The separation can be done on a variety of commercial C₁₈ reverse-phase columns.     

Determination of Methacholine Chloride by Ion-Pair High-Pressure Liquid Chromatography

Abstract

A method of analysis of methacholine chloride is presented, which is adaptable to other choline esters. The method uses ion-pair high-pressure liquid chromatography. Using 1-heptane sulfonic acid optically transparent at low UV wavelengths as the specific ion-pair, it was possible to assay for a specific choline ester using ultraviolet detection at 210 nm without interference by hydrolytic by-products. The method can be used to provide quality control and stability data on methacholine chloride in 0.9% sodium chloride solutions.     

Semipreparative High-Pressure Liquid Chromatography of Synthetic Carbohydrates

Abstract

A rapid and effective method has been developed for the purification of hundred-milligram quantities of water-soluble synthetic carbohydrates. The method utilizes a 30 cm x 7.8 mm i.d. column packed with Waters Associates carbohydrate analysis packing in conjunction with isocratic water-acetonitrile elution and refractive index detection. The generality of this method is illustrated by its application to 13 sucrose derivatives and one derivative each of D-fructose and α,α-trehalose.     

Quantitative Separation of Volatile Fatty Acids by High-Pressure Liquid Chromatography

Abstract

Volatile fatty acids (acetic, propionic, butyric, isovaleric, and valeric) are separated isocratically on a reverse phase C₁₈ μBONDAPAK column in less than 20 min. The eluent was 0.01 M NaH₂PO₄ buffer, pH 3.5, containing 10% methanol. Separations were monitored by UV absorption at 210 nm. Peak height measurements gave quantitative linear responses from 0.25 μmole to 2.50 μmole of each acid.     

High-Pressure Liquid Chromatography Separation of Potential Impurities of Altretamine

Abstract

Two isocratic liquid chromatographic separation methods and UV detection were developed to allow for sensitive and specific analysis of potential impurities in Altretamine using a reversed phase C₁₈ column and mixtures of water-acetonitrile as mobile phase. Linear calibration curves for each of the possible contaminants of Altretamine, in the range of 0.25–125 μg/ml, were also obtained. The detection limit for all of the compounds (except cyanuric acid) was less than 0.25 μg/ml. Several Altretamine lots were examined and their impurities identified. Hydrolysis of cyanuric chloride to cyanuric acid was studied and shown to follow 1^st order kinetics. Evidence for the formation of chlorohydroxytriazine intermediates during the hydrolysis of cyanuric chloride to cyanuric acid is given.     

Determination of Fluoroquinolone Antibiotics in Industrial Wastewater by High-Pressure Liquid Chromatography and Thin-Layer Chromatography—Densitometric Methods

JPC – Journal of Planar Chromatography – Modern TLC - Two methods were described for the simultaneous determination of ciprofloxacin HCl (CIP) and moxifloxacin HCl (MOX) in their binary...     

Determination of Penicillinase-Resistant Penicillins In Serum Using High-Pressure Liquid Chromatography

Abstract

A method for the determination of methicillin, oxacillin, cloxacillin, dicloxacillin, and nafcillin in serum using high-pressure liquid chromatography (HPLC) is described. The drugs were extracted from serum using a two-step procedure employing acetonitrile followed by methylene chloride. The extraction procedure concentrated the antibiotics in a smaller volume which allows more accurate determinations of low serum levels. The treated sera were analyzed by HPLC on a reverse-phase column and detected by ultraviolet light absorption at 254 nm. Serum concentrations were measurable as low as 0.5 μg/ml. Recovery procedures showed less than 2.5% variation in peak heights when the antibiotics were extracted from different pools of serum. No interfering absorption was found in extracts of serum samples pooled from healthy volunteers, from a commercial source, or from two serum pools from patients receiving a variety of other drugs. Two spiked serum specimens prepared for each antibiotic were assayed four times by HPLC and by the microbiological agar diffusion method. No significant statistical differences between the methods were observed. Control materials were assayed for between-batch and within-batch reproducibility in the presence or absence of an internal standard. Results for between-batch reproducibility demonstrate CV's of about 5%. This procedure provides a sensitive, specific, accurate, and rapid method for determining antibiotic levels in routine clinical specimens.     

Measurement of Cellulolytic Activity by Low Pressure Liquid Chromatography

Abstract

The application of aqueous, low pressure liquid chromatography to the assay of cellulolytic enzyme activity is discussed. The advantages of this method are speed of analysis (less than 20 min.), small sample size (20 μl), good resolution, and a tolerance of the system to the presence of extraneous salts and proteins. Examples showing the use of this tool are given.     

Direct Combination of High-Pressure Liquid Chromatography and Atomic Absorption for the Analysis of Metallorganic Compounds

Abstract

A routine atomic absorption spectrometer has been used as a detector to monitor the effluents from a high-pressure liquid chromatograph. This rapid, plug-in combination allows the selective, high-sensitivity determination of the individual inorganic and metallorganic compounds of the element of interest, resolved by the chromatographic column. The application to the analysis of lead alkyls, both in synthetic mixtures and in commercial gasoline, is illustrated.     

The Chemistry and Biology of Soluble Guanylate Cyclase Stimulators and Activators

The vasodilatory properties of nitric oxide (NO) have been utilized in pharmacotherapy for more than 130 years. Still today, NO‐donor drugs are important in the management of cardiovascular diseases. However, inhaled NO or drugs releasing NO and organic nitrates are associated with noteworthy therapeutic shortcomings, including resistance to NO in some disease states, the development of tolerance during long‐term treatment, and nonspecific effects, such as post‐translational modification of proteins. The beneficial actions of NO are mediated by stimulation of soluble guanylate cyclase (sGC), a heme‐containing enzyme which produces the intracellular signaling molecule cyclic guanosine monophosphate (cGMP). Recently, two classes of compounds have been discovered that amplify the function of sGC in a NO‐independent manner, the so‐called sGC stimulators and sGC activators. The most advanced drug, the sGC stimulator riociguat, has successfully undergone Phase III clinical trials for different forms of pulmonary hypertension.     

The Use of Decanol for Improving Chromatographic Stability in Isocratic Non-Aqueous Reversedphase Analysis of Carotenoids by High-Pressure Liquid Chromatography

Abstract

A non-aqueous isocratic solvent system for reversed-phase analysis of a full range of carotenoids from polar to non-polar is described. The major advance in the method is the use of n-decanol added at 0.1% by volume as modifier to a mobile phase of ethyl acetate-acetonitrile. The presence of the modifier rapidly conditions new columns and avoids problems with trace solvent impurities, both of which would otherwise give unsatisfactory chromatographic behaviour. In the absence of n-decanol, activation of residual silanol groups in the reversed-phase packing can cause a drastic deterioration in column behaviour. The method is rapid, versatile and simple. Information on separation conditions, solvent effects, column conditioning and carotenoid response curves is given.     

反相高效液相色谱法测定磷酸果糖激酶的活性

采用反相高效液相法(RP-HPLC)测定磷酸果糖激酶的活性.将磷酸果糖激酶与含有果糖-6-磷酸和ATP的反应体系混合,置于30℃水浴中,反应20 min后,沸水浴3 min终止反应.通过RP-HPLC测定酶反应前后产物二磷酸腺苷(ADP)量的变化来分析酶的活性.ADP的生成量在5～400 mg/L范围内具有良好的线性关系,方法的精密度良好(RSD<5%).本方法与通常所用的酶偶联法(ECM)相比准确度高,且简便易行.     

Determination of Thiamphenicol in Serum and Cerebrospinal Fluid with High-Pressure Liquid Chromatography

Abstract

A procedure for quantitation of thiamphenicol in serum and cerebrospinal fluid was developed using high-pressure liquid chromatography. The drug was extracted from biological samples with methanol and separated by reverse-phase high-pressure liquid chromatography. Detection and subsequent quantitation were performed at 254 nm by on-line ultraviolet spectrophotometry. After the intramuscular administration of a single dose of 1 g of thiamphenicol to a patient, a poor transmission of the drug across the hematoencephalic barrier was demonstrated by this assay.     

高效液相色谱法测定寡糖链结构

以葡聚寡糖为模型分子，经甲基化，乙酰氯／盐酸裂解，( )-MNB甲酸荧光衍生化及高效液相色谱分析，建立一种新的寡糖链结构分析方法。该方法可以同时获得组成单糖种类、糖链分支位点及组成单糖的D，L-陶型3种结构信息。操作简单，分析灵敏度为0．2pmol，分析周期在5h以内。     

Analysis of Vegetable Oils by High-Performance Liquid Chromatography

A reversed-phase high-performance liquid chromatographic procedure is proposed to monitor the fatty-acid and triglyceride composition of sunflower-seed oil. The procedure uses a column packed with Diasfer-110-C₁₈ (6 m), a 2 : 8 mixture of acetonitrile and acetone as an eluent, and refractometric detection. Analyses that use simple normalization and normalization with correction factors that take into account the difference between calculated refraction coefficients of different triglycerides are compared. It is shown that the proposed procedure can be used for the quantitative determination of total triglycerides in various vegetable oils as well.     

炔敌稗的高效液相色谱分析

炔敌稗(proyzamide),其化学名称是3,5-二氯-N-(1,1-二甲基丙炔基)苯甲酰胺,是一种应用广泛的除草剂,常用于阔叶杂草(wild oats,john grass,ryegrass)等杂草的控制.目前,只有用高效液相色谱法检测其在环境中残留量的报道,但该方法所用试剂昂贵,操作繁琐,不适用于产品的质量分析,本文建立了测定炔敌稗有效成分的高效液相色谱定量分析方法,并利用质谱(MS)、核磁共振(NMR)确定其中的主要杂质为3-氯-N-(1,1.二甲基丙炔基)苯甲酰胺.该方法可用于产品的质量检测.2 实验部分2.1 仪器与试剂 P200型高效液相色谱系统,可变波长紫外检测器,WDL-95色谱工作站,样品过滤器(国家色谱分析中心,大连依利特科学仪器有限公司),数据用WDL-95色谱工作站在联想P5/100微机上处理.Bruk-er Ac-P200核磁共振仪.HP5989质谱仪.炔敌稗粉剂(50%)为Rohm-Haas公司产品;水为二次蒸馏水;甲醇为色谱纯;炔敌稗标准(自制).     

Determination of Solasodine in Fruits of Solanum Khasianum by a Combination of Chromatofuge and High-Pressure Liquid Chromatography

Abstract

An extract of Solanum khasianum fruits was fractionated with a chromatofuge. The fraction containing solasodine was applied to a HPLC column and the effluent was monitored by UV. The peak height gave an accurate measure of the amount present. The efficiency and load capacity of the chromatofuge, as well as the accuracy and precision of the HPLC method were determined.     

高效液相色谱法测定人体红细胞中儿茶酚氧位甲基转移酶的活性

 采用高效液相色谱紫外检测法测定人体红细胞中儿茶酚氧位甲基转移酶 (COMT)的活性。以 3,4 二羟基苯甲酸 (DBA)作为酶反应底物 ,S 腺苷甲硫氨酸 (SAM)作为甲基供体 ,在镁离子的存在下 ,将SAM上的甲基转移到DBA 3位的氧上。色谱法测定反应产物 4 羟基 3 甲氧基苯甲酸 (4 OH 3 MBA)的生成量。人体红细胞中COMT活性的线性范围在 1U/mL～ 6 0U/mL ,最低检测限为 0 5U/mL(S/N≥ 5 ) ,方法的精密度良好 (平均RSD <10 % )。