AIMS: To compare plasma ascorbic acid results by the colorimetric FRASC (Ferric Reducing/Antioxidant and Ascorbic Acid) assay and a reference HPLC method; to re-examine plasma ascorbic acid stability, and anticoagulant effect. DESIGN AND METHODS: For method comparison, 31 plasma samples were tested by both methods. For stability, matching EDTA, heparin, citrate and fluoride/oxalate plasma, stored under different conditions of time and temperature, was measured. RESULTS: FRASC is an acceptable alternative to HPLC for plasma ascorbic acid: precision, limit of detection and recovery were similar, and results by the two methods were indistinguishable: mean (95% CI) difference:1.8 (-1.1-4.6; n = 31) micromol/L. Ascorbic acid was most stable in heparinized plasma. Marked loss (p < 0.05) in EDTA plasma occurred within 30 min of blood collection. CONCLUSIONS: FRASC offers a speedy and reliable alternative to HPLC for plasma ascorbic acid. Heparin is proposed as the anticoagulant of choice; loss of ascorbic acid is rapid in EDTA plasma ex vivo.
AIMS: To compare plasma ascorbic acid results by the colorimetric FRASC (Ferric Reducing/Antioxidant and Ascorbic Acid) assay and a reference HPLC method; to re-examine plasma ascorbic acid stability, and anticoagulant effect. DESIGN AND METHODS: For method comparison, 31 plasma samples were tested by both methods. For stability, matching EDTA, heparin, citrate and fluoride/oxalate plasma, stored under different conditions of time and temperature, was measured. RESULTS: FRASC is an acceptable alternative to HPLC for plasma ascorbic acid: precision, limit of detection and recovery were similar, and results by the two methods were indistinguishable: mean (95% CI) difference:1.8 (-1.1-4.6; n = 31) micromol/L. Ascorbic acid was most stable in heparinized plasma. Marked loss (p < 0.05) in EDTA plasma occurred within 30 min of blood collection. CONCLUSIONS: FRASC offers a speedy and reliable alternative to HPLC for plasma ascorbic acid. Heparin is proposed as the anticoagulant of choice; loss of ascorbic acid is rapid in EDTA plasma ex vivo.
Authors: Rae S M Yeung; Salvatore Albani; Brian M Feldman; Elizabeth Mellins; Berent Prakken; Lucy R Wedderburn Journal: Nat Rev Rheumatol Date: 2016-09-22 Impact factor: 20.543
Authors: Zuo Hang Yu; Christopher J Reinhardt; Thomas Hin-Fung Wong; Ka Yan Tong; Jefferson Chan; Ho Yu Au-Yeung Journal: Chemistry Date: 2020-06-25 Impact factor: 5.236