Determination of Ascorbic Acid (Vitamin C) by Direct Injection Enthalpimetry (DIE) Technique The ascorbic acid content of juices of some fruits and pharmaceutical tablets of Vitamin C was determined by a homemade apparatus of DIE technique using a thermoc. (2017). Ibn AL-Haitham Journal For Pure and Applied Sciences, 25(1). https://jih.uobaghdad.edu.iq/index.php/j/article/view/681