High-performance liquid chromatographic determination of zinc pyrithione in antidandruff preparations based on copper chelate formation

A simple and rapid method for the determination of zinc pyrithione (ZPT) in antidandruff preparations by high-performance liquid chromatography (HPLC) has been developed. ZPT in samples was converted into a stable copper(II) complex by mixing with cupric sulphate solution followed by extraction with chloroform. HPLC was carried out on a Nucleosil 5 C18 column (15 cm X 4.6 mm I.D.) using methanol-water (3:2) as the mobile phase with UV detection at 320 nm. The calibration graph was linear from 0.1-0.5 micrograms for ZPT. The recoveries from four shampoos were 98.0-100.6% with high accuracy.     

Determination of the antifouling agent zinc pyrithione in water samples by copper chelate formation and high-performance liquid chromatography-atmospheric pressure chemical ionisation mass spectrometry

Zinc pyrithione has recently been incorporated into antifouling paints as a booster biocide, which is slowly released into the water as the paint ages. In order to determine concentrations of zinc pyrithione (ZPT) in aqueous samples, a liquid chromatographic method has been developed. Since ZPT interacts with certain reversed-phase packing materials or stainless steel components of the HPLC system, the method uses transchelation of the ZPT into the stable copper(II) complex before analysis by liquid chromatography coupled to atmospheric pressure chemical ionisation mass spectrometry. ZPT was extracted as copper pyrithione using dichloromethane with adequate recovery (77% +/- 17%, n = 6) from 2-l water samples. The limit of detection was calculated to be 20 ng/l, using selected ion monitoring. The analysis of samples collected from various UK marinas showed no detectable concentrations to be present, whilst a laboratory-based study confirmed that this is probably due to the rapid photodegradation of ZPT in seawater.     

Hair Colors: Classification,Chemistry and a Review of Chromatographic and Electrophoretic Methods for Analysis

Abstract

At present, the demand for hair color is rising globally. Because commercial hair colors have been reported to possess adverse effects on human health, their formulation is under strict regulation in each country. In this review, we briefly discuss the advantages and limitations of currently available chromatographic and electrophoretic methods, such as high performance liquid chromatography (HPLC), gas chromatography/gas chromatography with mass spectrometry (GC/GC-MS), and capillary electrophoresis (CE) employed for the analysis of dyestuffs present in commercial hair colors. Furthermore, a brief attempt has been made to classify hair colors according to their type and stability on hair. In addition, the chemistry behind dyeing is also briefly surveyed.     

Quantitative HPLC Analysis of Plasma Amino Acids as Orthophthaldialdehyde/Ethanethiol Derivatives

Abstract

A reverse phase high performance liquid chromatographic method for the analysis of plasma amino acids is described. The method employs pre-column derivatization with o-phthaldialdehyde using ethanethiol as the reducing agent. The analysis shows good linearity and reproducibility. An average overall difference of 12% was seen for results obtained by the HPLC method versus those obtained with an amino acid analyzer. The chromatographic parameters of buffer concentration and column temperature were also examined.     

Enzymatic Estimation and Quantitative High-Pressure Liquid Chromatography of Fructose,Glucose and Sucrose in Powders from Rose Petals

Abstract

There was no significant difference between mean mass fractions of fructose, glucose and sucrose measured enzymatically and by liquid chromatography. So the chromatographic method can be used on powders from rose petals as the peaks of the chromatograms are really caused by the sugars.

A method is described for clean-up of the rose extract before injecting it into the high-pressure liquid chromatograph.     

Analysis of Dexamethasone Acetate in Pharmaceutical Formulations by HPLC

Abstract

A rapid and effective high-pressure liquid chromatographic method has been developed for the quantitative determination of dexamethasone 21 acetate in pharmaceutical formulations. Sample preparation employs a simple extraction procedure and analysis is carried out on a reversephase chromatographic system using a LiChrosorb RP 18 column and a water-acetonitrile as mobile phase. The extraction procedure gives quantitative recovery and chromatographic results show that drug levels of as 0.1 ppm can be conveniently analyzed without significant background interferences.     

An Improved Analysis of the Pheromone 3-Methyl-2-Cyclohexen-1-One in a Controlled Release Formulation by Using Liquid Chromatography

Abstract

A method was developed for estimating the quantity of the pheromone 3-methyl-2-cyclohexen-1-one in a controlled release formulation. The thermal method measured the amount of releasable pheromone remaining in the formulation by using liquid chromatography with a variable wavelength ultraviolet detector. This method is 150 to 250 times more sensitive than the liquid chromatographic method used previously.     

Purification of Commercially Prepared Bovine Trypsin by Reverse Phase High Performance Liquid Chromatography

Abstract

A reverse phase high performance liquid chromatographic method for the purification of milligram amounts of commercially prepared bovine trypsin is described. Increased specific enzymatic activity is observed in the purified material. The advantages of using purified trypsin in protein digestions as well as the potential application of reverse phase high performance liquid chromatography for enzyme characterization are described.     

Hair Analysis as Method for Determination of Level of Drugs and Pharmaceutical in Human Body: Review of Chromatographic Procedures

Abstract

Interest in hair analysis as an alternativ or complementary approach to urinalysis for drug abuse detection has grown in recent years. Hair analysis can be particularly advantageous for drugs and their enantiomers.

More than hundred pharmaceuticals, drugs of abuse agents are reported to be detectable in human and animal hair. This article reviews the aalysis of drugs and drug metabolites by chromatographic procedures, incuding the pretreatment steps, and the xtraction methods. Tihe eneral tendency in the last years, to highly sophisticated techiques gas chromatography–mass spectrometry (GC–MS–NCI), high pressure liquid chromatography–mass spectrometry (HPLC–MS), gas chromatography–mass spectrometry–mass spectrometry (GC–MS–MS) well illustrates this constant fight for sensitivity.     

An Improved Microanalytical Procedure for the Quantitation of Procainamide and N-Acetyl Procainamide in Serum by High-Performance Liquid Chromatography

Abstract

A high-performance liquid chromatographic method for analysis of procainamide (PA), and N-acetyl procainamide (NAPA) is presented. Sample preparation employs a simple base-acid double extraction procedure and analysis is carried out on a reverse phase chromatographic system using a μBondapak C₁₈ column and buffered aqueous acetonitrile as the mobile phase. The extraction procedure gives quantitative recovery of both PA and NAPA, and chromatographic results show that drug levels of as low as 0.3 mg per liter of serum can be conveniently analyzed without significant background interferences. The small volume (0.2 ml) of serum needed to perform an analysis makes this method suitable for pharmacokinetic studies in humans and animals as well as for clinical therapeutic drug monitoring studies.     

Catalytic Determination of Selenium in Human Hair by Polarography Using Glutathione

Abstract

A catalytic polarographic method has been proposed for the accurate determination of selenium in human hair. This method is based on the formation of Se(0)-GSH complex in alkaline medium which gives a catalytic reduction wave in polarography. The current observed is directly proportional to the amount of selenium present. The method has been applied for the determination of selenium in human hair and the recovery of added selenium from hair is found to be 97.5 to 102%. A suitable mechanism for the reduction process involving the catalytic reduction of oxidised glutathione is proposed.     

Stability-Indicating High-Pressure Liquid Chromatographic Assay for L-Lysine

Abstract

A high-pressure liquid chromatographic method for the assay of L-Lysine is described. L-lysine was derivatized by reacting with 2,4-dinitrofluorobenzene. A fixed wavelength detector (254 nm) and a LiChrosorb RP-18, 10 μm, Hibar-II column from MCB Manufacturing Chemists, Inc., was employed. The method is simple, precise, accurate and stability-indicating.     

Active TBC in Butadiene by HPLC

Abstract

A high performance liquid chromatographic method has been developed for the determination of active 4-tert-butyl-catechol (TBC) In 1,3-butadiene. Following evaporation of the butadiene from an aqueous m-nitrophenol internal standard solution, a 20-microliter aliquot is injected onto a reversed-phase liquid chromatographic column. Recovery op TBC was found to be quantitative over a 17-242 ppm range with a relative standard deviation of 3.8%.     

A Comparison and Clinical Applications of Ammonium Acetate and Phosphate Based Mobile Phases for the Separation of Catecholamines on Reversed Phase Columns

Abstract

A novel ion paired high performance liquid chromatographic system on reversed phase columns with ammonium acetate buffer as eluent is described for the separation of catecholamines. The advantages of using ammonium acetate buffer have been systematically studied and compared with the more widely employed phosphate buffer. The applicability of the method was demonstrated by analysis of catecholamines in clinical specimens.     

The Analysis of Penicillins in Biological Fluids and Pharmaceutical Preparations by High-Performance Liquid Chromatography: A Review

Abstract

High performance liquid chromatographic methods for the analysis of penicillins in biological fluids and pharmaceutical preparations are reviewed. In particular, sample preparation and handling procedures, chromatographic conditions and detection methods are discussed. A summary of published high performance liquid chromatographic assays for individual penicillins is included.     

Routine Preparative HPLC of Aromatic Silyl Compounds on Caffeine Coated on Silica Gel

Abstract

A liquid chromatographic method using caffeine coated on silica gel, for separation and purification of acenaphthenylsilyl compounds is described. This has been achieved on a preparative scale.     

HPLC Determination of Carbendazim in Formulations

Abstract

A rapid high performance liquid chromatographic method has been developed to determine Carbendazim (methyl 2-benzimidazole carbamate) in formulations using reverse phase μ Bondapak C₁₈ column and ultraviolet detection. The sample is extracted from formulations with methanol, carbaryl is used as an internal standard. Absorbance is measured at 254 nm and the compound is quantitated by peak height ratios. The method is simple and recoveries averaged between 91–93%.     

Determination of Plasma Pseudo-Ephedrine by Fluorescence Detection and High Performance Liquid Chromatography

Abstract

A sensitive and specific high-performance liquid chromatographic method has been developed for the determination of pseudoephedrine in plasma. The assay was based on the production of a highly fluorescent derivative of pseudoephedrine using 4-chloro-7-nitrobenzo-2, 1, 3-oxadiazole (NBD-Cl) as the derivatization agent. The fluorescent derivatives were separated using normal phase liquid chromatography after an automated, column-switching, sample clean-up procedure. Pseudoephedrine determination was accurate and precise at concentrations as low as 10 nanograms per milliliter of plasma. The chromatographic step separated derivatives of pseudoephedrine from those of norpseudoephedrine and several other amines. Measurement of pseudoephedrine concentrations in plasma following a single 120 milligram oral dose is illustrated.     

A Simultaneous Analysis by High Performance Liquid Chromatography of Bamipine Combined with Tricyclic Antidepressants and/or Antipsychotics in Dosage Forms

Abstract

A reversed phase high-performance liquid chromatographic method is described for the simultaneous determination of antihistamines, tricyclic antidepressants and anti-psychotics in pharmaceutical formulations and in spiked placebos. The separation was performed on an octadecyl-silica column using acetonitrile: tetrahydrofuran: 0.015 M aqueous ammonium acetate (53:42: 5) as mobile phase. The presence of ammonium acetate both shortens the elution time and improves the symmetry of the chromatographic peaks. Measurements were made at 251 nm.     

Determination of Ethosuximide,Phenobarbital, Carbamazepine,Carbamazepine Epoxide and Phenytoin in Serum by high performance liquid chromatography using Radially compressed Columns and an Aqueous methanolic mobile phase

Abstract

A liquid chromatographic method for the determination of antiepileptic drugs in serum is described. The drugs were adsorbed on activated charcoal from which they were recovered by extraction with methylene chloride. The organic extracts were evaporated to dryness and the residues were dissolved in small volumes of the mobile phase. The extracts were clean. Only trace amounts of endogenic compounds were detected. The chromatographic separation was performed with a radially compressed column (C18) that was used daily for several months.