Simultaneous enantioselective determination of fenamiphos and its two metabolites in soil sample by CE.

The enantioseparation of fenamiphos and its two main metabolites (fenamiphos sulfoxide and fenamiphos sulfone) were simultaneously achieved by CE by using a dual CD system. A mixture of 25 mM carboxymethyl-beta-CD and 10 mM hydroxypropyl-alpha-CD was added to the acetic acid/ammonia (ionic strength=50 mM, pH 5) buffer and was suitable for the baseline resolution of all stereoisomers of analytes. A further addition of 5% methanol to the BGE increased significantly the resolution between the diastereoisomers of fenamiphos sulfoxide.

Sensitivity improvement by using contactless conductivity rather than indirect UV detection for the determination of enantiomeric purity of amines by CE.

A capacitively coupled contactless conductivity detection (C4D) system for CE with a flexible detection cell was applied for the enantioseparation of small chiral underivatized amines using chiral crown ether or CD as chiral selector. Since these compounds are poorly UV-active, C4D was an alternative detection mode. The composition (ionic strength, pH, chiral selector) of the electrolyte was optimized in order to be suitable for C4D.

Chiral analysis of milnacipran by a nonchiral HPLC--circular dichroism: improvement of the linearity of dichroic response by temperature control.

The determination of the enantiomeric excess (e.e.) of a basic drug has been investigated in LC using a nonchiral stationary phase and a circular dichroism (CD) detector in order to avoid expensive chiral columns.

Simultaneous determination of optical and chemical purities of a drug with two chiral centers by liquid chromatography-circular dichroism detection on a non-chiral stationary phase.

The need for a rapid and cheap chromatographic technique for the simultaneous determination of diastereoisomeric and chemical purities of a drug has led to develop a non-enantioselective HPLC method on a porous graphitic carbon (PGC) sorbent and by using circular dichroism (CD) detection. Among a lot of non-chiral chromatographic supports tested, PGC was the only one allowing the separation of all benzoxathiepin diastereoisomers. After optimization of the chromatographic conditions, a mobile phase composed of chloroform, acetonitrile and methanol was suitable to elute the diastereoisomers with their related chemical impurities in less than 20 min by gradient mode.