This paper describes a strategy for the development of chromatographic methods for drug candidates based upon the use of simple MS compatible mobile phases and optimization of the chromatographic selectivity through variations of the stationary phase and mobile phase pH. The strategy employs an automated column selection system and a series of HPLC columns, varying in hydrophobicity and silanol...

Revisions and additional material can be found on SeQuant's website (www.sequant.com). Questions and comments regarding the content in this booklet can be e-mailed to [email protected]. An introduction and troubleshooting manual Foreword This guide will show you some of the most common practical issues that occur during analysis of anions by ion chromatography. Many users find the technique diff...

the search for new stationary phases has been one of the predominant concerns in high performance liquid chromatography (hplc) in order to achieve better resolutions, longer column lives, and reduce the time of analysis. a chromatographic packing for separation of underivatized amino acids (aas) were prepared by dynamically coating 2-amino tetraphenyl prophyrin (atpp) on a c-18 reversed-phase p...

A prototype analyser incorporating commercial analytical instrumentation has been used to monitor the sucrose contamination of boiler feed water. The instrument has been designed to use a commercially available pulsed amperometric detector and incorporates a short chromatographic column. This allows the choice of flow-injection or chromatographic mode of operation. The former is simpler, but no...

two modified methods for assaying sodium diclofenac were developed by gc and hplc. diclofenac was converted into methyl ester derivative by methyl iodide in acetone. the ester was extract and subjected to glc with flame ionization detector. %5 se-30/chrom w-hp (80-100 mesh) was used as a column in gc. for reversed phase hplc, the mobile phase was methanol and water (55-45). the separation was p...

abstract        background and objective: measurement of amino acids is an important tool for metabolic studies and evaluation of patients’ clinical condition. the aim of this study was to analyze the plasma amino acids using reverse phase high performance liquid chromatography techniques (rp-hplc) with pre-column derivatization by o-phthalaldehyde (opa) in combination with 3- mercaptopropionic...

The review describes on-line derivatization/degradation methods employed in mass spectrometry to solve some structural and analytical problems. Advantages and applications of various positions of reaction systems connected mainly to a mass spectrometer or a gas chromatograph/mass spectrometer are considered. Among these are reaction systems connected directly to the mass spectrometer (reaction ...

A high-pressure liquid chromatographic method for the determination of norfloxacin or ciprofloxacin concentrations in body fluids was developed and compared with a standard bioassay. The high-pressure liquid chromatographic assay utilizes a reverse-phase C18 column, an internal standard, and fluorescence detection, with reproducibility studies yielding coefficients of variation ranging from 0.6...

We describe an isothermal gas-liquid chromatographic procedure developed for measuring thiamylal and thiopental in plasma. The unchanged drug is extracted into ethyl acetate from acidified plasma, together with an internal standard. The solvent is removed, the residue methylated, aliquots, diluted with benzene, are injected into a 183-cm gas-liquid chromatographic column containing 3% OV-17. Se...

A highly sensitive gas chromatographic assay is described for the simultaneous determination of gallopamil, a calcium channel blocking agent, and its major metabolite, norgallopamil. A multi-step extraction procedure is employed followed by on-column capillary gas chromatographic analysis using nitrogen-selective detection. Acetylation of norgallopamil is performed to enable accurate quantifica...