Validation of chiral capillary electrophoresis-electrospray ionization-mass spectrometry methods for ecstasy and methadone in plasma.

Due to its selectivity and sensitivity, CE coupled to MS (CE-MS) has evolved as a useful analytical tool for determining drugs and metabolites in biological samples. A generic CE-ESI/MS method was developed for the enantioselective determination of basic compounds in plasma. The use of protein precipitation (PP) prior to a hydrodynamic injection (HD) was well adapted to high-concentration samples (>1 ppm) and allowed high throughput.

Rapid determination of pK (a) values of 20 amino acids by CZE with UV and capacitively coupled contactless conductivity detections.

A rapid and universal capillary zone electrophoresis (CZE) method was developed to determine the dissociation constants (pK (a)) of the 20 standard proteogenic amino acids. Since some amino acids are poorly detected by UV, capacitively coupled contactless conductivity detection (C(4)D) was used as an additional detection mode. The C(4)D coupling proved to be very successful on a conventional CE-UV instrument, neither inducing supplementary analyses nor instrument modification.

Coupling CE with atmospheric pressure photoionization MS for pharmaceutical basic compounds: optimization of operating parameters.

The use of CE coupled with MS (CE-MS) has evolved as a useful tool to analyze charged species in small sample volumes. Because of its sensitivity, versatility and ease of implementation, the ESI interface is currently the method of choice to hyphenate CE to MS. An alternative can be the atmospheric pressure photoionization (APPI) source, however, numerous parameters must be optimized for its coupling to CE.

Enhanced method performances for conventional and chiral CE-ESI/MS analyses in plasma.

Due to its high efficiency, selectivity, and sensitivity, CE-ESI/MS has evolved as an efficient technique for the drugs and metabolites analysis in biological matrices. However, a sample preparation is mandatory prior to CE-ESI/MS analysis. To achieve fast and simplified sample preparation of plasma samples, protein precipitation (PP) and liquid-liquid extraction (LLE) were used with two injection techniques: hydrodynamic (HD) and electrokinetic (EK) injection.

Rapid stereoselective separations of amphetamine derivatives with highly sulfated gamma-cyclodextrin.

The highly sulfated gamma-CD (HS-gamma-CD) is a chiral selector widely used in CE for the enantioseparation of pharmaceutical compounds. This paper investigated different approaches to reduce the stereoselective analysis time of amphetamine (AT) derivatives according to the chiral selector concentration in the BGE. With high HS-gamma-CD concentration, tested analytes were separated in 3.

Ultrashort partial-filling technique in capillary electrophoresis for infinite resolution of tramadol enantiomers and its metabolites with highly sulfated cyclodextrins.

The possibility to enhance resolution to infinite value in chiral capillary electrophoresis is attained as soon as the apparent mobility of one enantiomer becomes opposite to the other. This could be achieved on the basis of the carrier ability of multiple charged chiral selectors such as highly sulfated cyclodextrin (HS-CD). With tramadol and its phase I metabolites selected as model compounds, the HS-gamma-CD was found to be the most appropriate chiral selector.

Infinite enantiomeric resolution of basic compounds using highly sulfated cyclodextrin as chiral selector in capillary electrophoresis.

Four chiral basic analytes, namely methadone, fluoxetine, venlafaxine, and tramadol, were selected as model compounds for investigating their stereoselective separation with highly sulfated gamma-cyclodextrin (HS gamma-CD) by capillary electrophoresis (CE)-UV and CE-mass spectrometry (MS). At high concentration of chiral selector, the preferentially bonded enantiomer migrated faster in the anodic mode to the detector and high resolutions were obtained for all analytes. In the cathodic mode, at lower highly sulphated cyclodextrin (HS-CD) concentration, basic compounds could be detected, with the weakly bonded enantiomer migrating first (enantiomeric migration order inversion).