Liquid chromatography of guanidino compounds using a porous graphite carbon column and application to their analysis in serum

Utility of porous graphitic carbon stationary phase in quantitative liquid chromatography/tandem mass spectrometry bioanalysis: quantitation of diastereomers in plasma

“…Although PGC columns have been used in the separation of diastereomers5, 13, 14 and polar analytes,7, 19–21 only a few applications have been reported for bioanalytical quantitation 8–14. It is essential to establish the ruggedness of the PGC column, in terms of maintenance of its separation capability, sensitivity, peak symmetry and back pressure, when used for extended period for analyzing biological samples by LC/MS/MS.…”

“…This stationary phase has been used for the separation of positional isomers, such as equine conjugated estrogens, equilin sulfate and Δ8,9‐dehydroestrone sulfate,6 as well as for separating some polar compounds, such as nucleosides and their mono‐, di‐, and triphosphates 7. To our knowledge, there are only a few published methods using a PGC column for bioanalytical quantitation, such as the separation and quantitation of 5‐fluorouracil, 5‐fluorodihydrouracil and its prodrug ftorafur in serum,8, 9 guanidine compounds in serum,10, 11 glutathione in plasma,12 and isoprostanes in urine and cerebrospinal fluid 13, 14…”

Quantitation of polar analytes using column-switching: Application to oxycodone and three metabolites in human plasma

“…hydrophobic) interactions, graphite is responsible of for charge-induced interactions between polarizable or polar groups of the analyte, which leads to an improved retention for polar and ionic compounds [5]. Bioanalytical methods for polar compounds were reported for nucleobase derivatives [6][7][8][9], gluthatione derivates [10] and other polar drugs [11][12][13][14].…”

Molecularly imprinted solid‐phase extraction combined with molecularly imprinted polymer‐sensor: a diagnostic tool applicable to creatine deficiency syndrome

“…Whereas non-separation assays [enzymatic (Beyer, 1993;Yasuhara et al, 1981;Bayer and Alting, 1996;Jiao et al, 1998;Marymont et al, 1968;Ronner et al, 1999), fluorometry (Herbert et al, 1974), sensor (Stefan et al, 2003a,b), mass spectrometry (Rozaklis et al, 2002), fluoroscene (Subrahmanyam et al, 2000), and adsorptive stripping square wave voltammetry (Stojanova et al, 1999)] are reportedly cumbersome, separation methods [capillary electrophoresis (Yan et al, 1999;Burke et al, 1999;Zinellu et al, 2005) and highperformance liquid chromatography (HPLC) (Yang et al, 1998;Smith-Palmer, 2002;Persky et al, 2003)] usually involved a complicated methodology with critical problems of prerequisite sample pretreatment and prederivatization (Smith-Palmer, 2002;Kai et al, 1983Kai et al, , 1984Boppana and Rhodes, 1990;Inamoto et al, 1998). To date, an array of hyphenated techniques [e.g.…”