Diphenylamine and derivatives as predictors of gunpowder age by means of HPLC and statistical models

The gunpowder age is information of great importance that could help to establish safety regulations related to the propellants use and manipulation. In this work, a forced aging treatment (65 °C for 120 days) was applied to four gunpowders stabilized with diphenylamine (DPA). The evolution of DPA and derivatives (N-nitroso-DPA, 2-nitro-DPA, 4-nitro-DPA, and 4-4′-dinitro-DPA) concentration during the days was leaded by High Performance Liquid Chromatography (HPLC). The variation with time of the peak areas of these compounds was used to construct different statistical models that could predict the gunpowders age. These models were validated using nitrocellulose-based gunpowders of known manufacture date. Models that best predicted the gunpowder age provided prediction errors lower than 6, 4, and 2 years for single-base gunpowders with dinitrotoluene (≥10% (m/m)), single-base gunpowders and double-base gunpowders, respectively.

► Diphenylamine and derivatives have been extracted from gunpowders submitted to force aging.
► The variation, as a function of time, of HPLC peak areas of these compounds has been followed.
► A simple and fast mathematical model to predict the aging of gunpowders has been designed and validated.
► Errors in age prediction of 33 gunpowders of known manufacture date were lower than six years.
► This model may help military laboratories to improve protocols for a safe handling of propellants.