Developing Novel Methods For The Detection Of Creatinine And Phospholipids

The metabolome is defined as the complete set of metabolites present in an organism, which is widely used in potential molecular biomarkers for disease diagnosis. As most studied body fluids, urine and blood plasma are of importance in human metabolomics research. Hence, various analytical methods and platforms have been developed. In this work, two novel materials were proposed for the fast and accuracy determination of creatinine in human urine and phospholipids(PLs) in blood plasma. Moreover urine metabolic profiling analysis was performed between Uygur and Han groups. Concrete research content including following three aspects:(1) The direct determination of creatinine was achieved using a poly(ethyleneimine)/phosphotungstic acid multilayer modified electrode with the assistance of Copper(II) ions by cyclic voltammetry. The quantity of creatinine were determined by measuring the redox peak current of Cu(II)-creatinine complex/Cu(I)-creatinine complex. Factors affecting the response current of creatinine at the modified electrode were optimized. A linear relationship between the response current and the concentration of creatinine ranging from 0.125 to 62.5 μM was obtained with a detection limit of 0.06 μM. The proposed method was applied to determine creatinine in human urine, and satisfied results were gotten which was validated in accordance with high performance liquid chromatography. The sensor can be used repeatedly and has widely applied prospect in clinical practice.(2) Firstly, ethylenediamine tetraacetic acid(EDTA)-functionalized Fe3O4(EDTA@Fe3O4) were prepared by one-pot chemical co-precipitation method. And then Zr(IV) was immobilized on EDTA@Fe3O4 through chelating interaction. The as-prepared Zr(IV) chelating magnetic nanoparticles(Zr(IV)-IMAC) were characterized by TEM and EDS. It showed strong magnetic responsiveness to an applied magnetic field. The beads were used to enrich PLs with four standard PLs as models coupled with reversed-phase liquid chromatography-evaporative light scattering detection(RPLC-ELSD). Under optimum conditions, recoveries of four PLs were more than 94.23%. Coupled with ultra performance liquid chromatography with quadrupole time-of-flight mass spectrometry(UPLC-QTOF), 47 PLs were determined from human plasma. Above results demonstrated that as-prepared Zr(IV)-IMAC exhibited high selectivity and specificity to PLs.(3) In this chapter, urine metabolomics analysis was performed to explore the difference between Uygur and Han. And one method was developed to analysis the metabolites based on ultra performance liquid chromatography-mass spectrometry platform. Totally 128 urine samples were collected(64 for each ethnic groups). Limited by the large number of samples, the work was just partly done. More UPLC-QTOF analyses need performed in further.