Determination of ascorbic acid in plasma and serum: Method and stability studies

Ascorbic acid is a kind of vitamin which can melt in water and is taken by dietary by primats, people and some kind of animals and takes place in many biochemical reactions and pHysiologic processes. Recent studies show that ascorbic acid can be an indicator of general healt condition and also can be used in the treatment with major diseases such as cancer and diabetes.Vitamin C, is a molecule which can easily degregate because of its chemical structure. Ascorbic acid converts into dehydroascorbic acid by giving one hydrogen of en-diol group. It is tought that the reason of degregation is enviromental conditions (PH, light, oxygen concentration, divalent cations, oxidant enzymes). In the measurement of the amount of ascorbic acid in blood, the unstable structure of ascorbic acid effects the reability of measurement. So the importance of pre-analytical factors is increasing in ascorbic acid measurements.The aim of the study is to improve different sample preparing methods by using different measurement techniques in different environment conditions. The effects of time on ascorbic acid measurement, storage conditions at different temperatures, adding MPA to the samples, HPLC and spectrophotometric techniques and anticoagulants that are used at taking blood samples are investigated.Serum and plasma samples were obtained from 10 cattle aged 4-6. After serum and plasma are obtained they are divided into five different groups to be exposed to different enviromental conditionals, MPA is added to half of it and it is analyzed using both HPLC and spectrophotometric technics. The results obtained are statistically evaluated. The blood samples which are taken by using EDTA anticoagulant are found to be significiantly reduced. But any significiant diffrence was detected in the samples which were left at different environmental conditions. Important differences were detected in the samples which are treated and not treated with MPA. Ascorbic acid concentration is found less in the samples which are aded MPA. Ascorbic acid concentrations which are measured by using spectrophotometric technic were found numerically at great amounts.As a result; quick measurement of ascorbic acid in serum and plasma and necessity of using heparin tubes rather than EDTA tubes are adviced. On the other hand, in the light of the findings of this study it can be said that more studies should be done with more samples.Key words: Ascorbic acid, stability, HPLC