title: Accurate quantification of creatinine in serum by coupling a measurement standard to extractive electrospray ionization mass spectrometry.
abstract: Ambient ionization (AI) techniques have been widely used in chemistry, medicine, material science, environmental science, forensic science. AI takes advantage of direct desorption/ionization of chemicals in raw samples under ambient environmental conditions with minimal or no sample preparation. However, its quantitative accuracy is restricted by matrix effects during the ionization process. To improve the quantitative accuracy of AI, a matrix reference material, which is a particular form of measurement standard, was coupled to an AI technique in this study. Consequently the analyte concentration in a complex matrix can be easily quantified with high accuracy. As a demonstration, this novel method was applied for the accurate quantification of creatinine in serum by using extractive electrospray ionization (EESI) mass spectrometry. Over the concentration range investigated (0.166 ~ 1.617 μg/mL), a calibration curve was obtained with a satisfactory linearity (R(2) = 0.994), and acceptable relative standard deviations (RSD) of 4.6 ~ 8.0% (n = 6). Finally, the creatinine concentration value of a serum sample was determined to be 36.18 ± 1.08 μg/mL, which is in excellent agreement with the certified value of 35.16 ± 0.39 μg/mL.
authors.affiliation: State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun, 130012, P. R. China.
authors.forename: Keke
authors.initials: K
authors.lastname: Huang
authors.affiliation: Chemistry Department, National Institute of Metrology, Beijing, 100013, P. R. China.
authors.forename: Ming
authors.initials: M
authors.lastname: Li
authors.affiliation: Chemistry Department, National Institute of Metrology, Beijing, 100013, P. R. China.
authors.forename: Hongmei
authors.initials: H
authors.lastname: Li
authors.affiliation: Chemistry Department, National Institute of Metrology, Beijing, 100013, P. R. China.
authors.forename: Mengwan
authors.initials: M
authors.lastname: Li
authors.affiliation: Chemistry Department, National Institute of Metrology, Beijing, 100013, P. R. China.
authors.forename: You
authors.initials: Y
authors.lastname: Jiang
authors.affiliation: Chemistry Department, National Institute of Metrology, Beijing, 100013, P. R. China.
authors.forename: Xiang
authors.initials: X
authors.lastname: Fang
mesh_terms: D015415:Biomarkers; D002853:Chromatography, Liquid; D003404:Creatinine / Q000097:blood*; D006801:Humans; D015203:Reproducibility of Results; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods / Q000592:standards
chemical_list: D015415:Biomarkers; D003404:Creatinine