It has been used in the synthesis of (1-ethyl-propyl)-[3-(4-methoxy-2-methylphenyl)-2-methyl-6,7-dihydro-5H-1,4,8a-triaza-s-indacen-8-yl]-amine, in the synthesis of monoclinic VPO4·H2O, as internal standard in the screening of aziridine and 2-chloroethylamine in active pharmaceutical ingredients by gas chromatography-mass spectrometry. It has been used in the synthesis of (1-ethyl-propyl)-[3-(4-methoxy-2-methylphenyl)-2-methyl-6,7-dihydro-5H-1,4,8a-triaza-s-indacen-8-yl]-amine, in the synthesis of monoclinic VPO4·H2O, as internal standard in the screening of aziridine and 2-chloroethylamine in active pharmaceutical ingredients by gas chromatography-mass spectrometry.