In this study, an analytical method for determination of two ketamine precursors, 1 - [(2-chlorophenyl) methyllimino methyl] cyclopentanol hydroclorid (CCM) and 2-Hydroxy-2 - (o-chloro phenyl) cyclohexanon (HCH), in wastewater using solid phase extraction (SPE) and liquid chromatogrphy tandem mass spectrometry (LC-MS / MS) was developed and validated.