A sensitive and specific high-performance liquid chromatography (HPLC) method based upon laser-based polarimetric detection is developed for the determination of six tetracycline analogues. By interfacing the laser-based polarimeter online with an HPLC system, the specific rotation of each analogue is obtained as compounds elute from the separation system. The six structurally similar tetracycl...

In medical practices, the determination of enantiomeric ratio of the chiral drugs is very important for their activities, bioavailabilities and biodegradation. Only homochiral medication is safe for humans. The chiral analysis in biological samples is the first and most important step. The present article describes the technical strategies of the enantiomeric resolution of racemic drugs in biol...

The principles involved in the selection of solvents and the use of counter ions, together with the choice of column, for the separation of phospholipids by highperformance liquid chromatography (HPLC) are described.

Aerobic biodegradation behavior of nonylphenol propoxylates was investigated using dispersive liquid-liquid microextraction as a simple and fast technique for sample preparation. The developed method proved to be efficient for the isolation and concentration of nonylphenol propoxylates before their quantification with the use of high performance liquid chromatography. The primary biodegradation...

This study shows that HPLC-LALLS (high performance liquid chromatography with a light-scattering detector) is a convenient and reliable method for the characterization of standard heparin samples, provided that polyelectrolyte artefacts are suppressed by a suitable dialysis procedure. The method has been successfully applied to the assessment of calibrated relations like the Mark-Houwink relati...

Quantification of tocotrienols in human plasma is critical when the attention towards tocotrienols on its distinctive properties is arising. We aim to develop a simple and practical normal-phase high performance liquid chromatography method to quantify the amount of four tocotrienol homologues in human plasma. Using both the external and internal standards, tocotrienol homologues were quantifie...

Most of the common organic solvents are excreted into urine as metabolites. A correlation exists for several organic solvents between the amount taken in and the amount of metabolites excreted. Many methods have been developed for the measurement of these urinary metabolites. The methods were classified into three group: colorimetry, gas chromatography and high performance liquid chromatography...

The use of all chromatographic modes (i.e. reversed-phase, normal-phase and polar organic modes) is becoming more and more systematic in chiral HPLC method development. When this method development is monitored by polarimetric detection, which is a widespread technique, one should not forget that the observed positive or negative rotation angle for a given absolute configuration depends on the ...

Size-exclusion chromatography coupled with SAXS (small-angle X-ray scattering), often performed using a flow-through capillary, should allow direct collection of monodisperse sample data. However, capillary fouling issues and non-baseline-resolved peaks can hamper its efficacy. The UltraScan solution modeler (US-SOMO) HPLC-SAXS (high-performance liquid chromatography coupled with SAXS) module p...

We investigated the efficacy and utility of a post-column derivatization method for the detection of amines with o-phthalaldehyde (OPA) in ultra high-performance liquid chromatography (UHPLC). Since it was anticipated that a derivatization reaction system placed downstream of the column would give considerable band broadening to narrow peaks generated by a UHPLC column, we examined the contribu...