The Determination of Sodium Monofluoroacetate (Compound 1080) in Formulation and Technical Samples by High Pressure Liquid Chromatography

Abstract

A high pressure liquid chromatographic (HPLC) procedure was developed for the determination of sodium monofluoroacetate (Compound 1080). The procedure utilized an amine (NH₂) bonded column for the reverse phase determination of sodium monofluoroacetate in formulation and technical samples.     

A Rapid Method For Cyclosporine A Determination By Hplc

Abstract

A rapid method is described for the determination of cyclo-sporine in whole blood by HPLC. The cyclosporine is extracted with an acetonitrile-isopropanol mixture, purified on a C₁₈ minicolumn, and finally injected on a CN column. Recovery of the drug is greater than 90%.     

Determination of Some Penicillin Derivativies Using High Performance Liquid Chromatography

Abstract

A rapid, precise and selective method is described for determination of penicillin derivatives. Penicillin derivatives are separated from closely related degradation products by high performance liquid chromatography at ambient temperature using 10cm column packed with 5um Nucleosil RP₁₈ and buffered aqueous acetonitrile as mobile phase. The eluate is monitored at 254nm. The procedure is suitable for determination of 8 penicillin derivatives either in raw material or phamaceutical dosage forms.     

HPLC Determination of Oxalic Acid in Cocoa

Abstract

An HPLC method is described for the determination of oxalic acid in cocoa and milk chocolate. Samples are extracted using 6N HCI; after extraction the pH of an aliquot is adjusted to 6.0 and interfering substances are eliminated through the use of a C₁₈ Sep-pak®. The final HPLC determination uses a monolayer reversed phase column with an ion-pairing mobile phase and electrochemical detection. The results indicate excellent accuracy and precision.     

Voltammetric Characteristics of Adenine and Adenosine at a Copper Electrode and Their Application to End-Column Amperometric Detection for Capillary Zone Electrophoresis

Abstract

The voltammetric characteristics of adenine and adenosine at a copper electrode were investigated in different supporting electrolytes. It was found that citric acid had some activating effect at the copper electrode and the oxidation reaction of adenine and adenosine at the copper electrode could be observed in the solution, if PO₄ ^3? and citric acid exist simultaneously. The oxidation reaction of adenine and adenosine could be applied to capillary zone electrophoresis with end column amperometric detection for their determination. The method was applied to the determination of adenine in yeast-RNA.     

High Performance Liquid Chromatogrphy of Fat-Soluble Vitamins. III. Determination of Vitamin D3 in Pharmaceutical Preparations and in Blood

Abstract

A reversed phase high-performance liquid chromatographic method (HPLC) is described for separation and determination of colecalciferol (Vitamin D₃) in Vitamin preparations and in biological materials. Vitamin D₃ is extracted from the formulations and from the blood in a fully automated electronically controlled extraction apparatus. For HPLC a column of lichrosorb RP18 and methanol as eluent are used. The extraction, separation and determination of vitamin D₃ needs about 10–20 minutes. The described extraction and HPLC methods allow the detection of 1–2 ng per injection and are well reproduced with a maximum coefficient of variation of < 3,5%. Vitamin A-acetate is used as internal standard.     

Determination of Copper by Faas After Preconcentration with Lead-4-Methylpiperidinedithiocarbamate on Microcrystalline Naphthalene By Solid Phase Extraction

ABSTRACT

By using the Pb-4-methylpiperidinedithiocarbamate complex (Pb(4-MPDC)₂) on microcrystalline naphthalene in a column a method was developed for the preconcentration of copper in water samples prior to its determination by FAAS. In this method, copper in liquid phase quantitatively replaces lead on the Pb(4-MPDC)₂-naphthalene solid phase in the column, forming solid Cu(4-MPDC)₂ complex.

Afterwards, copper on Cu(4-MPDC)₂-naphthalene can be easily eluted by potassium cyanide into the aqueous phase, and the Cu is measured by FAAS. The optimum experimental parameters such as pH, flow rate, sample volume, Pb(4-MPDC)₂-naphthalene ratio, concentration of the potassium cyanide solution and effect of matrix ions for the preconcentration of copper were investigated. The obtained recovery was nearly 100 %, when the enrichment factor was 100 for standard solutions and spiked water samples. The proposed method has been employed for the determination of copper in various standard metal alloys and natural water samples.     

High-Performance Liquid Chromatography of Fungicides in Citrus Fruits

Abstract

The determination of three common citrus fungicides, diphenyl (DP), o-phenylphenol (oPP) and thiabendazole (TBZ), was investigated with reversed-phase high-performance liquid chromatography. DP and oPP were successfully chromatographed and quantitated by utilizing a reversed-phase Unisil Q C₁₈ column after extraction with an essential oil distillation apparatus. An acetonitrile-0.1M H₃PO₄ (55:45) mobile phase was used. TBZ was chromatographed by using a Unisil Q C₈ column with a mobile phase of acetonitrile-0.1M H₃PO₄ (80:20) after the extraction with ethyl acetate. The fungicides were detected with fluorescence detection at typical residue levels on citrus. The     

A Sorbent Extraction Procedure for the Preconcentration of Gold,Silver and Palladium on an Activated Carbon Column

ABSTRACT

A preconcentration method based on the use of an activated carbon column has been established for flame atomic absorption spectrometric determinations of gold, silver and palladium. The analytes were sorbed on the column as a complex of dithiophosphoric acid O, O-diethyl ester (DDTP). The sorbed analytes were eluted through the column with 2M NH₃ in acetone. Quantitative recoveries (≥95 %) for gold, silver and palladium were obtained from acidic solutions. The developing method was successfully applied to the determination of trace amounts of gold, silver and palladium in some samples with satisfactory results (relative standard deviation < 7 %; relative error < 3 %).     

On-Line Monitoring of Formaldehyde In Water and Air Using Chemiluminescence Detection

A rapid and sensitive chemiluminescence flow sensor for the determination of formaldehyde was proposed in this article. The analytical reagents involved in chemiluminescence (CL) reaction, luminol and KIO₄, were both immobilized on an anion-exchange column. The CL signal produced by the reaction between luminol and KIO₄, which were eluted from the column through water injection, was decreased in the presence of formaldehyde. Formaldehyde was sensed by measuring the decrement of CL intensity, which was observed linear over the logarithm of formaldehyde concentration range of 5.0-1000.0 ng mL^?1, and the limit of detection is 1.8 ng mL^?1 (3σ). At a flow rate of 2.0 mL min^?1, including sampling and washing, could be performed in 0.5 min with a relative standard deviation of less than 3.0%. The flow sensor offered reagentless procedures and remarkable stability in determination of formaldehyde, and could be easily re-used over 80 h. The proposed flow microsensor was applied successfully in the determination of formaldehyde in artificial water samples and air.     

Bulk Acoustic Wave Sensor for Non-suppressed Ion Chromatographic Determination of Nitrate and Other Inorganic Anions in Vegetables

Abstract

A new type of bulk acoustic wave sensing device based on a conductivity-bulk acoustic wave frequency response is applied in ion chromatography to determine nitrate and other inorganic ions in vegetables. The present method has the advantages in its rapidity, simplicity, sensitivity and accuracy. Detection limits (peak=3[sgrave]) are obtained for NO₃ ^?, Cl^?, NO₂ ^?, H₂PO₄ ^? and SO₄ ^2? at concentrations of 1, 0.6, 1, 7 and 3 ng (on column), respectively. Neither derivatization nor a clean-up step is necessary besides filtration. For the IC analysis, the analytical column is a Shim-pack IC AI column, and the eluent is 2.0 mM phthalic acid solution with pH 4.0. A comparison of IC-SBAW with conventional IC is made. The method allows the simultaneous determination of nitrate and other inorganic ion levels in vegetables.     

Determination of Tetracycline and Related Compounds by High-Performance Liquid Chromatography

Abstract

An isocratic high-performance liquid chromatography method for the determination of tetracycline and its related compounds is described. The method uses a reverse phase (C₁₈) column, a modified acetonitrile/water mobile phase, and banzoic acid as the internal standard. Elution of all compounds of interest is complete within seven minutes. Results are presented for thirteen commercial capsule formulations and are compared with results by microbiological assay and thin-layer chromatographic methods.     

Solid-Phase Extraction and Capillary Gas Chromatographic Determination of Triazine Herbicides in Water

Abstract

A facile and efficient method is described for the determination of trace quantities of triazine herbicides, terbutryn, prometryn and ametryn in water. The procedure involved preconcentration of water samples by sorption on chromatographic grade silica gel particles with chemically modified surface, being covalently bonded with a nonofunctional C₈H₁₇ group. This was followed by solvent desorption with 2-propanol. The determinative step was achieved by capillary gas chromatography on Supelcowax-10 fused silica column using a nitrogen-phosphorus detector. The limit of detection was 0.1 μg-10 μgL^?1.     

The Rapid Determination of Neopterine in Human Urine by Isocratic High-Performance Liquid Chromatography

Abstract

An isocratic high-performance liquid chromatography method is described for the determination of Neopterine eliminated in human urine, using a μ-Bondapak C₁₈ column (300 × 3.9 mm I.D.) and a strongly polar phosphate buffer (pH 6.2) for elution. This analysis requires only 15 minutes and allows very good reproduc-tibility of retention times. This method is well-suited for automation and routine clinical laboratory in order to quantify human urinary Neopterine in healthy subjects and in subjects with malignant disorders.     

High Pressure Liquid Chromatographic Determination of Isoniazid and Acetylisoniazid in Human Plasma

Abstract

A quantitative high pressure liquid chromatographic (HPLC) assay has been developed for the determination of isoniazid (INH) and acetylisoniazid (ACINH) in human plasma. Plasma samples were taken from a patient after oral administration of INH (with proven tuberculosis infection). A C₁₈ reversed phase radial compression column was used to separate INH and ACINH from other plasma components. The analysis takes 10 minutes per sample and the lower limit of detection for each compound is 0.10 ug/ml plasma.     

An Accurate,Specific HPLC Method for the Analysis of a Decapeptide in a Lactose Matrix

Abstract

A high-performance liquid chromatographic (HPLC) method is described for the determination of an analog of the hormone LH-RH in lyophilized vials at the low parts-per-million level. The peptide (Schally analog) is quantitatively recovered from the glass lyophilization vials after reconstitution with mobile phase. The peptide solution is eluted on a reversed-phase, C₁₈ column and monitored with ultraviolet (UV) detection at 220 nm. The chromatography resolves Schally analog from a number of synthetic impurities and decomposition products.     

A Rapid Isocratic Reversed-Phase Separation and Determination of Some Barbiturates by High-Performance Liquid Chromatography

Abstract

A high performance liquid chromatographic method for the rapid separation and quantitative determination of five barbiturates in pharmaceutical preparations and body fluids has been developed. A C₁₈ reversed phase column was used and the barbiturates were detected at 235nm.

A number of eluting systems were examined, the most suitable of them being, Ethanol:Propanol:Methanol:Water (26:5:29:40) at pH = 8.8.     

Assay of Arginine-Esterase Activities by Reversed Phase High Performance Liquid Chromatography

Abstract

Application of a high performance liquid chromato-graphic technique to assay of arginine-esterase activities is presented. Enzyme reaction was carried out with benzoyl-L-arginine ethylester as a substrate and analysis was performed on a reversed phase chromato-graphic system using a μ Bondapak C₁₈ or a Radial-PAK A column and buffered aqueous methanol as the mobile phase. The enzyme activities were determined by the peak height of cleaved product (benzoyl-L-arginine). The minimum detection limit for benzoyl-L-arginine was 0.02 nM on each column. The generality of this method was demonstrated by its application to determination of plasmin activity, and so it might be suitable for both kinetic studies and routine assays of plasmin-like es-terases.     

The Submicrodetermination of Carbon and Hydrogen in organic Compounds by A Gas-Chromatographic Method

Abstract

Preliminary studies on the development of a method for the determination of carbon and hydrogen in 50–100 μg samples of organic compounds are described. The sample is burned over copper oxide in a helium stream and the water formed is converted to acetylene. Separation of CO₂ and acetylene on a silica gel column is followed by combustion of acetylene to carbon dioxide; the two peaks remain separate and are measured by a highly sensitive katharometer.     

Determination of Apomorphine in Tablets Using High Performance Liquid Chromatography with Electrochemical Detection

Abstract

A rapid and selective method using high performance liquid chromatography with electrochemical detection is described for the determination of apomorphine in tablets. Tablet mixes were dissolved in a standard volume of mobile phase containing the internal standard, N-n-propylnorapomorphine. Separation was achieved on a μ-phenyl column using methanol-acetonitrile-0.05M KH₂PO₄ (5:15:80) as mobile phase. The eluted compounds were detected with a sandwich-type electrochemical detector employing a glassy carbon working electrode and operated at 0.5V. Satisfactory accuracy and precision were obtained during analyses of tablets containing apomorphine.