Possibilities of column coupling electrophoresis provided with a fiber-based diode array detection in enantioselective analysis of drugs in pharmaceutical and clinical samples

Column Coupling Electrophoresis in Biomedical Analysis

“…It is because such method provides probably one of the most acceptable ratio simplicitycost: universality-concentration LOD in comparison to other column coupling methods and detection systems. This suggestion is supported by many advanced applications of the ITP-CZE-UV method in the pharmaceutical and biomedical field (Marák et al, 2007;Mikuš et al, 2008aMikuš et al, , 2008bMikuš et al, , 2008cMikuš et al, , 2009. Jumps in voltage (conductivity) between neighboring zones result in permanently sharp boundaries between zones (Fig.…”

“…This analytical approach enabled us to obtain pure zones of the drugs enantiomers (without the need of the sample pretreatment). DAD spectra of PHM metabolites were compared with the reference spectra of PHM enantiomers (Marák et al, 2007;Mikuš et al, 2008c) and a very good match was found which indicated the similarities in the structures of enantiomers and their metabolites detected in the urine samples. This fact was utilized for the quantitative analyses of PHM metabolites in the urine samples by applying the calibration parameters of PHM enantiomers also for PHM metabolites.…”

“…Hence, the ITP-CZE method can be easily modified with a great variety of selectors implemented with the highest advantage into the CZE stage enabling to separate also the most problematic analytes (structural analogs, isomers, enantiomers). The ITP-CZE methods with chiral as well as achiral CZE mode have been successfully applied in various real situations (Mikuš et al, , 2008a(Mikuš et al, , 2008cDanková et al, 2001;Marák et al, 2007;Kvasnička et al, 2001). The most frequently used ITP-CZE system works in the hydrodynamically closed separation mode that is advantageous for the real analyses of multicomponent ionic mixtures because of the best premises for enhancing sample load capacity (enables using capillaries with very large I.D.).…”

“…Capillary (CE) and microchip (MCE) formats were taken into consideration. CE and MCE determinations of various biologically active compounds in model (spiked samples) as well as real biological matrices, employing an on-line coupling of the electrophoretic methods with other electrophoretic or non electrophoretic methods, are listed in (Mikuš et al, , 2008a(Mikuš et al, , 2008b(Mikuš et al, , 2008c(Mikuš et al, , 2009Marák et al, 2007) we illustrated possibilities of ITP-EKC method combined with diode array detection (DAD) for the direct achiral (celiprolol, CEL, amlodipine, AML) as well as chiral (amlodipine, AML, pheniramine, PHM, dimethinden, DIM and dioxoprometazine, DIO) quantitative determination of trace drugs in clinical human urine samples, see an example in Fig.15. ITP, on-line coupled with EKC, served in these cases as an ideal injection technique (high sample load capacity, preseparation and preconcentration) producing analyte zone suitable for its direct detection and quantitation in EKC stage.…”

“…Spectral DAD, used in our works, in comparison with single wavelength ultraviolet detection enhanced value of analytical information (i) verifying purity (i.e., spectral homogeneity) of drug zone (according to differences in spectrum profiles when compared tested and reference drug spectra) and (ii) indicating zones/peaks with spectra similar to the drug spectrum (potential structurally related metabolites). Very good selectivity was achieved by using a negatively charged carboxyethyl--cyclodextrin (CE--CD) as a chiral selector for enantioseparation and determination of trace (ng/mL) antihistaminic drugs (PHM, DIM, DIO) present in urine (Mikuš et al, , 2008cMarák et al, 2007). Charged chiral selector provided significantly different affinity towards the analytes on one hand and sample matrix constituents on the other hand; enabling the analytes can be transferred into the analytical stage without any spacers and multiple column-switching even if accompanied by a part of sample matrix constituents detectable in analytical stage.…”