In the present work, we describe the electrochemical behaviour of two opioids structurally related to aroyl amides of forensic interest, namely U-47700 and AH-7921. The data obtained allowed for the mise-au-point of a voltammetric determination protocol, that relies on differential pulse voltammetry (DPV) at a glassy carbon electrode in ethanol/0.1 M lithium perchlorate/0.10 M 2,6-lutidine. To apply the method to the analysis of real samples (urines), a clean-up and a preconcentration strategy by solid phase extraction (SPE) using the adsorbent Florisil have been developed. LOQ of 0.2 μg·mL⁻¹ in urine samples with an enrichment factor of 20 and linear range from 5 to 150 μg·mL⁻¹ were obtained.