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Updated: Jul 6, 2026
A Rapid and Specific Microplate Assay for the Determination of Intra- and Extracellular Ascorbate in Cultured Cells
Published on: April 11, 2014
Plasma ascorbic acid preparation and storage for epidemiological studies using TCA precipitation
1Department of Health and Functional Capacity, Biomarker Laboratory, National Public Health Institute, Helsinki, Finland. irma.salminen@ktl.fi
Objectives:
To introduce a procedure to validate an ascorbic acid method using trichloroacetic acid (TCA) for plasma stabilization at different storage temperatures.
Methods:
EDTA and heparin plasma were precipitated with TCA (1:5) containing 0.54 mol/L EDTA, or without. Samples were stored at -20 degrees C and -70 degrees C and their stability was tested at room temperature for 24 h.
Results:
A significant 40% loss (p<0.001) of plasma ascorbic acid was found when EDTA samples with added EDTA were stored at -20 degrees C for 2-4 weeks compared with storage at -70 degrees C. Ascorbic acid in heparin plasma without added EDTA was most unstable and samples left at room temperature for 24 h lead to almost a total loss of ascorbic acid. Addition of EDTA to the TCA solution improved stability of samples of both plasma types at room temperature.
Conclusion:
The recommended procedure for ascorbic acid determination in plasma stabilized with TCA is immediate storage at -70 degrees C and inclusion of EDTA into the TCA solution.
