Stability of ascorbic acid in serum and plasma prior to analysis

• Published in: Annals of clinical biochemistry Vol. 39; no. 5; pp. 518 - 520
• Main Authors: Ching, Simon YL, Prins, Alex W, Beilby, John P
• Format: Journal Article
• Language: English
• Published: London, England SAGE Publications 01.09.2002; Royal Society of Medicine Press; Sage Publications Ltd
• Subjects: Analysis of Variance; Ascorbic Acid - blood; Ascorbic Acid - chemistry; Ascorbic Acid - metabolism; Biological and medical sciences; Blood Preservation - methods; Chromatography, High Pressure Liquid - methods; Drug Stability; Edetic Acid - pharmacology; Heparin - pharmacology; Humans; Investigative techniques, diagnostic techniques (general aspects); Medical sciences; Miscellaneous. Technology; Pathology. Cytology. Biochemistry. Spectrometry. Miscellaneous investigative techniques; Time Factors; Human; Ascorbic acid; Chemical stability; HPLC chromatography; Lithium; EDTA; Waiting time; Blood plasma; Sample preparation; Pre analytical step; Clinical biology; Sample conservation; Glycosaminoglycan; Serum; Heparin; Technique; Comparative study
• DOI: 10.1258/000456302320314566
• ISSN: 0004-5632

Introduction: The stability of ascorbic acid in serum and plasma prior to analysis was studied. Methods: Blood samples were collected from ten healthy subjects into Vacutainer tubes containing either dipotassium EDTA, lithium-heparin or no additive. Ascorbic acid was analysed following immediate separation and preservation of samples, following delayed separation for 2 h and after delayed deproteinization and preservation for 2, 5 and 8 h. Deproteinization and preservation were achieved using a solution containing perchloric acid, EDTA and dithiothreitol. Ascorbic acid was analysed by high-performance liquid chromatography. Results: Blood collected into EDTA and separated, deproteinized and preserved immediately gave the highest yield of ascorbic acid. Loss of analyte after delayed separation was least for EDTA tubes (median 7%, range 4-13%), followed by lithium-heparin (median 18%, range 10-32%) and serum (median 26%, range 14-50%). Immediate separation of samples but delayed deproteinization and preservation also resulted in substantial losses of ascorbic acid. Conclusion: Minimum loss of ascorbic acid is achieved if blood is collected into tubes containing dipotassium EDTA and separated within 2 h, followed by immediate deproteinization and preservation.