ABSTRACT
Surfactant-containing eluents are evaluated for possible application to direct serum injection using conventional reverse-phase columns. Serum albumin was quantitatively eluted at the column void volume by using surfactant concentrations below or above the critical micelle concentration, and organic solvents could be used in proportions as high as 40% (w/w). Surfactant choice, pH, and salt effects were also evaluated.
Subject(s)
Carbamazepine/blood , Chromatography, Liquid/methods , Serum Albumin/chemistry , Surface-Active Agents/chemistry , Xanthines/blood , Adsorption , Carbamazepine/analogs & derivatives , Hydrogen-Ion ConcentrationABSTRACT
Column switching is used in conjunction with surfactant containing mobile phases and traditional reverse phase LC columns to provide a highly reproducible and accurate analytical procedure for carbamazepine and its 10,11-epoxide in serum. This approach eliminates the tedious sample preparation steps commonly used in the analysis of drugs by HPLC, while providing a high degree of protein removal prior to the final analysis. Various pre-columns were investigated and a pellicular reverse phase column was found suitable for optimum concentration of drugs and removal of serum proteins. A variety of standard reverse phase columns could be used for the analytical separation. The separation of the drugs could be accomplished with a high degree of reproducibility. Tandem pre-column operation was demonstrated to give a sample throughput of 10 h-1.
Subject(s)
Carbamazepine/analogs & derivatives , Carbamazepine/blood , Drug Monitoring/methods , Chromatography, Liquid/instrumentation , Chromatography, Liquid/methods , Humans , Reproducibility of Results , Surface-Active Agents/analysisABSTRACT
Surfactant-containing eluents are evaluated for the analysis of carbamazepine in serum with conventional reversed-phase columns. Bovine serum was quantitatively eluted at the column void volume using surfactant concentrations in conventional reversed-phase eluents. The effect of pH, guard columns and column switching was evaluated with respect to separating and detecting clinical levels of the drug and its primary metabolite. Column lifetime was also investigated.
Subject(s)
Carbamazepine/blood , Chromatography, Liquid/methods , Animals , Carbamazepine/analogs & derivatives , Cattle , Chromatography, Liquid/instrumentation , Hydrogen-Ion ConcentrationABSTRACT
A new approach to the analysis of free amino acids and amino acids from hydrolyzed foods is described. The method is based on reaction of the free amino acids with phenylisothiocyanate to form stable derivatives which are subsequently separated by liquid chromatography. Sample preparation procedures are described and results are compared with conventional ion exchange results. Reproducibility of the new method has been determined on a typical food type sample.
Subject(s)
Amino Acids/analysis , Food Analysis/methods , Animal Feed/analysis , Animals , Bone and Bones/analysis , Cheese/analysis , Chromatography, Liquid , Flour/analysis , Hydrolysis , Indicators and Reagents , Isothiocyanates , Meat/analysis , Phenylthiourea , ThiocyanatesABSTRACT
Refined methods for separating PTC-amino acids on reverse phase columns may pose a challenge to traditional ion exchange techniques.
Subject(s)
Amino Acids/analysis , Thiocyanates , Chromatography, Liquid , Isothiocyanates , Methods , PhenylthioureaABSTRACT
A new approach to the pre-column derivatization and analysis of amino acids is described. The method is based upon formation of a phenylthiocarbamyl derivative of the amino acids. The derivatization method is rapid, efficient, sensitive, and specific for the analysis of primary and secondary amino acids in protein hydrolyzates. The liquid chromatographic system allows for the rapid, bonded-phase separation with ultraviolet detection of the common amino acids with 12-min analysis time and a 1-pmol sensitivity.
Subject(s)
Amino Acids/analysis , Chemical Phenomena , Chemistry , Drug Stability , Humans , Hydrolysis , Insulin/analysis , Isothiocyanates , Oxytocin/analysis , Peptides/analysis , Proteins/analysis , Spectrophotometry, Ultraviolet/methods , Thiocyanates , Trypsin/analysisABSTRACT
Unbonded silica gel is an effective support for reverse-phase liquid chromatographic separations of lipophilic amines. Simple buffered aqueous-organic mobile phases provide rapid isocratic separations of antihistamines. Phenylpropanolamine hydrochloride, chlorpheniramine maleate, and dextromethorphan hydrobromide are separated in 8 min on bare silica with a mobile phase of 75% methanol and 25% water which is 0.01 M in (NH4)2HPO4. Quantitation is reproducible. A wide variety of additional compounds may be separated using the same mobile phase.
