title: Graphitic carbon nitrides modified hollow fiber solid phase microextraction for extraction and determination of uric acid in urine and serum coupled with gas chromatography-mass spectrometry.
abstract: An elevated uric acid (UA) in urine or serum can affect renal function and blood pressure, which is an indicator of gout, cardiovascular and renal diseases, hypertension, etc. In this work, a new type of mixed matrix membrane (MMM), based on graphitic carbon nitrides (g-CNs) and hollow fiber (HF), was prepared and combined with solid phase microextraction (SPME) mode to determine UA in urine and serum followed by gas chromatography-mass spectrometry (GC/MS). The porous g-CNs were dispersed in ammonia, and then the exfoliated g-CNs nanosheets were held in the pores of HF by capillary forces and sonification. The prepared g-CNs modified HF (g-CNs-HF) was immersed in biofluid directly to extract UA with SPME mode and the solvent-free mode is convenient for further derivatization and analysis. To achieve the highest extraction efficiency (EF), main extraction and derivatization parameters, such as g-CNs-HF immobilizing time, sonification power and time of extraction, derivatization and desorption time, were optimized. Under the optimum extraction conditions, a favorable linearity of UA was obtained in the range 0.1-200μgmL(-1) with correlation coefficients higher than 0.9990, and the average recoveries at three spiked levels of UA in urine and serum ranged from 80.7% to 121.6%, from 84.7% to 101.1%, respectively. The obtained results demonstrated the developed g-CNs-HF-SPME is a simple, rapid, cost-effective, solvent-free method for the analysis of UA in biofluid.
authors.affiliation: Key Laboratory of Chemistry of Northwestern Plant Resources of the CAS and Key Laboratory for Natural Medicine of Gansu Province, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, People's Republic of China; University of Chinese Academy of Sciences, Beijing 100039, People's Republic of China.
authors.forename: Ying-pei
authors.initials: YP
authors.lastname: Sun
authors.affiliation: Key Laboratory of Chemistry of Northwestern Plant Resources of the CAS and Key Laboratory for Natural Medicine of Gansu Province, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, People's Republic of China.
authors.forename: Juan
authors.initials: J
authors.lastname: Chen
authors.affiliation: Key Laboratory of Chemistry of Northwestern Plant Resources of the CAS and Key Laboratory for Natural Medicine of Gansu Province, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, People's Republic of China. Electronic address: qihuanyang@licp.cas.cn.
authors.forename: Huan-yang
authors.initials: HY
authors.lastname: Qi
authors.affiliation: Key Laboratory of Chemistry of Northwestern Plant Resources of the CAS and Key Laboratory for Natural Medicine of Gansu Province, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, People's Republic of China. Electronic address: shiyp@licp.cas.cn.
authors.forename: Yan-ping
authors.initials: YP
authors.lastname: Shi
mesh_terms: D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D006108:Graphite / Q000737:chemistry*; D006801:Humans; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D009570:Nitriles / Q000737:chemistry*; D052617:Solid Phase Microextraction / Q000295:instrumentation*; D014527:Uric Acid / Q000097:blood* / Q000652:urine*; D014961:X-Ray Diffraction
chemical_list: D009570:Nitriles; D014527:Uric Acid; C011206:cyanogen; D006108:Graphite
keywords: Gas chromatography-mass spectrometry (GC/MS); Graphitic carbon nitrides (g-CNs); Hollow fiber (HF); Solid phase microextraction (SPME); Uric acid (UA)