Adsorption And Retention Of Polar Compounds By Porous Graphitized Carbon

Porous graphitized carbon?PGC?materials are widely used in sample pretreatment and chromatographic column materials.PGC is applied for solid phase extraction material to remove matrix effect in complex samples,eventually enriching target samples.On the other hand,PGC can serve as a liquid chromatography material to separate some polar compounds such as isomers,saccharides,amines and polychlorinated biphenyls,etc.Quantitative analysis of drugs in urine by high performance liquid chromatography electrospray-ionization-mass spectrometry?HPLC-ESI-MS?has been a challenging task due to the complex matrix interferences and the relatively low concentration of target analyte in urine.In this study,PGC was investigated as solid-phase extraction?SPE?sorbent before HPLC-MS/MS analysis of three typical serotonin type 3?5-HT₃?receptor antagonists from human urine.The PGC adsorbent can effectively eliminate matrix interferences and shows extremely high extraction efficiency for three target analytes including tropisetron?TRO?,ondansetron?OND?and granisetron?GRA?.The factors affecting extraction of the target antagonists were investigated and optimized systematically by using single-factor test.The optimized SPE procedure was developed for the simultaneous extraction and sample pretreatment of TRO,OND and GRA in urine by HPLC-ESI-MS/MS.Under optimized conditions,the level of matrix effects can be remarkably reduced,acceptable matrix effects of TRO,OND and GRA were respectively 96.53%-98.42%,93.19%-94.36%and94.48%-95.60%,respectively.The recoveries of 87.12-93.84%,88.88-98.13%and92.83%-98.93%from urine samples were obtained at the concentrations of 0.500-12.5 ng/mL for the target TRO,OND and GRA,respectively,with the RSDs lower than 6.30%.The linear range was 0.125-12.5 ng/mL with the correlation coefficient of greater than 0.9990 for the target TRO,OND and GRA in human urine samples.Satisfactory precision and accuracy of the proposed method were also obtained.Porous graphitized carbon in the analysis of aldose has been made a lot of applications over the years,but there are still many problems to be desperately solved and developed.Monosaccharide cannot be retained on the traditional chromatographic column of C₁₈8 and PGC,but after the derivative,its derivative compounds can not only be separated on the chromatographic column of C18/PGC,but also can be possessed of specific luminescence group,which can be directly luminescence probed in the liquid phase on the universal detector-ultraviolet detector of the peak.In this experiment,dibenzylamine was used for conducingt derivative reaction on several aldoses at the same time.The single factor test method was applied to optimize the conditions of the derivative experiment.In particular,an appropriate amount of water was added to the lipid reaction system to make the reaction system more diversified and suitable for different derivative reaction systems.Moreover,when the reaction balance has not basically unchanged,the original reaction time of 180minutes is shortened to 60 minutes,which is three times shorter,and the derivative reaction speed is greatly improved.Compared with other methods,the derivative reaction of dibenzylamine and aldoses has the advantages of mild reaction conditions,simple pretreatment and short reaction time.