Rafi O. Zaman Brohi et al.trans. 2016. Gas Chromatographic Determination of Purines and Pyrimidines from DNA Using Ethyl Chloroformate as Derivatizing Reagent. Pakistan Journal of Analytical & Environmental Chemistry. 17, 1 (Jan. 2016), 50 – 57. DOI:https://doi.org/10.21743/pjaec/2016.06.008.