title: Real Time Online Correction of Mass Shifts and Intensity Fluctuations in Extractive Electrospray Ionization Mass Spectrometry.
abstract: Real time online calibration of mass shift and intensity fluctuation to improve the accuracy of measurements for identification and quantitation in trace mass spectrometric analysis was demonstrated using extractive electrospray ionization mass spectrometry (EESI-MS). The signals of authentic compounds (e.g., lysine (Lys), proline (Pro), and histidine (His)) spiked into the extractive solution for the EESI process were used as the references to calibrate the signal of analytes (e.g., methionine (Met)) in the untreated sample solution. The intensity of the analyte signal was recorded simultaneously with the reference signals. The analyte signals at a given time point were calibrated on the basis of these correlation factors and real time signal response of the reference. The calibrated signal of Met at 10 μg L(-1) was improved with a better signal-to-noise ratio (S/N from 2.3 to 4.3), better linearity (R(2) from 0.9758 to 0.9980), and reduced relative standard deviation (RSD from 9.8% to 6.0%). The shift of mass-to-charge ratio of Met signal between the detected and theoretical values was decreased from 247 ± 133 to -7 ± 167 ppm for 50 min of detection using a linear ion trap mass analyzer and was reduced from -0.27 ± 0.60 to -0.12 ± 0.23 ppm for 50 min of detection using an Orbitrap mass analyzer (P = 95%). This method has been validated using a certified standard amino acids solution (GBW(E)100062) and applied for quantitative detection of amino acids in chicken feed, urine, nutritional drink, and facial mask samples, showing that the method is useful to improve the accuracy of mass spectrometric analysis.
authors.affiliation: State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences , Beijing 100085, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Tian
authors.affiliation: State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences , Beijing 100085, China.
authors.forename: Miao
authors.initials: M
authors.lastname: Yu
authors.affiliation: Jiangxi Key Laboratory for Mass Spectrometry and Instrumentation, College of Chemistry, Biology and Material Sciences, East China University of Technology , Nanchang, Jiangxi 330013, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences , Beijing 100085, China.
authors.forename: Chunxiao
authors.initials: C
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences , Beijing 100085, China.
authors.forename: Jianbo
authors.initials: J
authors.lastname: Shi
authors.affiliation: Jiangxi Key Laboratory for Mass Spectrometry and Instrumentation, College of Chemistry, Biology and Material Sciences, East China University of Technology , Nanchang, Jiangxi 330013, China.
authors.forename: Huanwen
authors.initials: H
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences , Beijing 100085, China.
authors.forename: Guibin
authors.initials: G
authors.lastname: Jiang
mesh_terms: D000596:Amino Acids / Q000737:chemistry / Q000652:urine; D002138:Calibration; D006801:Humans; D057230:Limit of Detection; D009862:Online Systems; D015203:Reproducibility of Results; D059629:Signal-To-Noise Ratio; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D000596:Amino Acids