Identification and quantification of 4-methylethcathinone (4-MEC) and 3,4-methylenedioxypyrovalerone (MDPV) in hair by LC-MS/MS after chronic administration
First method allowing simultaneously measurement of 4-MEC and MDPV in hair. Very sensitive method with LLOQ set at 1 pg/mg for both compounds. First 4-MEC result in hair in a chronic abuser of this compound.