Novel LC-MS-TOF method to detect and quantify ascorbic and uric acid simultaneously in different biological matrices

• Published in: Journal of chromatography. B, Analytical technologies in the biomedical and life sciences Vol. 1168; p. 122588
• Main Authors: Borras, Eva, Schrumpf, Leah, Stephens, Noelle, Weimer, Bart C., Davis, Cristina E., Schelegle, Edward S.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.04.2021
• Subjects: acetonitrile; antioxidants; Ascorbic acid; Biological matrices; condensates; Exhaled breath condensate (EBC); formic acid; isotopes; LC-MS-TOF; liquid chromatography; mass spectrometry; Nasal lavage; nose; Plasma; Quantification; Uric acid; Validation; Validation; Nasal lavage; Plasma; Biological matrices; Ascorbic acid; Quantification; Uric acid; LC-MS-TOF; Exhaled breath condensate (EBC)
• ISSN: 1570-0232; 1873-376X; 1873-376X
• DOI: 10.1016/j.jchromb.2021.122588

•A novel LC-MS-TOF method to quantify ascorbic and uric acid in biological samples.•Simple sample preparation adapted to each matrix with antixoidants stabilization.•Method validation with satisfactory results for breath, nasal lavage, and plasma. Ascorbic acid (AA) and uric acid (UA) are known as two of the major antioxidants in biological fluids. We report a novel liquid chromatography–mass spectrometry with time-of-flight (LC-MS-TOF) method for the simultaneous quantification of ascorbic and uric acids using MPA, antioxidant solution and acetonitrile as a protein precipitating agent. Both compounds were separated from interferences using a reverse phase C18 column with water and acetonitrile gradient elution (both with formic acid) and identified and quantified by MS in the negative ESI mode. Isotope labeled internal standards were also added to ensure the accuracy of the measures. The method was validated for exhaled breath condensate (EBC), nasal lavage (NL) and plasma samples by assessing selectivity, linearity, accuracy and precision, recovery and matrix effect and stability. Sample volumes below 250 µL were used and linear ranges were determined between 1 – 25 and 1 – 40 µg/mL for ascorbic and uric acid, respectively, for plasma samples, and between 0.05 – 5 (AA) and 0.05 – 7.5 (UA) µg/mL for EBC and NL samples. The new method was successfully applied to real samples from subjects that provided each of the studied matrices. Results showed higher amounts determined in plasma samples, with similar profiles for AA and UA in EBC and NL but at much lower concentrations.