Abdullah, A.M. 2017. 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. Ibn AL-Haitham Journal For Pure and Applied Sciences. 25, 1 (May 2017).