All around the world, the production and consumption of synthetic drugs such as New Psychoactive Substances is increasing, in which amphetamine type stimulants (ATS) such as 3,4-methylenedioxyethylamphetamine (MDEA) have been widely seized. Thus, the development of fast and simple analytical methods for the screening of these substances in seized drugs is very important. This work presents an electrochemical method for the screening of MDEA in drugs, using a commercial screen-printed carbon electrode (Dropsens®) and square wave voltammetry (SWV). Initially, the electrochemical behavior was studied by cyclic voltammetry in buffer Britton-Robinson 0.04 mol L-1 at different pHs (2 to 12), in which electrochemical mechanisms have been proposed for the observed processes. However, pH 3 was chosen considering better detectability and a higher number of identifiable peaks (Epa1 = + 0.21 V, Epa2 = + 0.87 V and Epc1 = + 0.15 V). Subsequently, the detection of MDEA was performed by SWV due to the higher sensitivity and sample throughput of the technique. Employing the optimized conditions (amplitude of 40 mV, frequency of 30 Hz and step potential of 4 mV) the following analytical parameters were obtained for peak 1 (Ep1 = 0.16 V) and peak 2 (Ep2 = 0.77 V), respectively: linear range from 5.0 to 50.0 µmol L-1 (R2 > 0.99), sensitivities of 0.217 and 0.144 µA / mol L-1 and limits of detection of 0.07 and 0.11 µmol L-1. The precision of the method was satisfactory, due to the low relative standard deviations (RSD) obtained in successive measurements (P1: RSD <6%; P2 RSD <10%; n = 10). The inter-electrode reproducibility (n = 5) was low in terms of peak current (RSD < 35.4%), but high for peak potentials (RSD < 2.3%). In the interferers study was verified the discrimination of MDEA from common adulterants such as caffeine, paracetamol, glucose and other ATS (amphetamine - A, methamphetamine - MA, 3,4-methylenedioxyamphetamine - MDA), except 3,4-methylenedioxymethamphetamine (MDMA). In addition, MDEA screening was carried out on drugs seized by the Civil Police-DF, and the results compared with those obtained by HPLC-MS. The developed method is fast, simple, pratical, portable and low cost, being promising for applications in forensic chemistry.All around the world, the production and consumption of synthetic drugs such as New Psychoactive Substances is increasing, in which amphetamine type stimulants (ATS) such as 3,4-methylenedioxyethylamphetamine (MDEA) have been widely seized. Thus, the development of fast and simple analytical methods for the screening of these substances in seized drugs is very important. This work presents an electrochemical method for the screening of MDEA in drugs, using a commercial screen-printed carbon electrode (Dropsens®) and square wave voltammetry (SWV). Initially, the electrochemical behavior was studied by cyclic voltammetry in buffer Britton-Robinson 0.04 mol L-1 at different pHs (2 to 12), in which electrochemical mechanisms have been proposed for the observed processes. However, pH 3 was chosen considering better detectability and a higher number of identifiable peaks (Epa1 = + 0.21 V, Epa2 = + 0.87 V and Epc1 = + 0.15 V). Subsequently, the detection of MDEA was performed by SWV due to the higher sensitivity and sample throughput of the technique. Employing the optimized conditions (amplitude of 40 mV, frequency of 30 Hz and step potential of 4 mV) the following analytical parameters were obtained for peak 1 (Ep1 = 0.16 V) and peak 2 (Ep2 = 0.77 V), respectively: linear range from 5.0 to 50.0 µmol L-1 (R2 > 0.99), sensitivities of 0.217 and 0.144 µA / mol L-1 and limits of detection of 0.07 and 0.11 µmol L-1. The precision of the method was satisfactory, due to the low relative standard deviations (RSD) obtained in successive measurements (P1: RSD <6%; P2 RSD <10%; n = 10). The inter-electrode reproducibility (n = 5) was low in terms of peak current (RSD < 35.4%), but high for peak potentials (RSD < 2.3%). In the interferers study was verified the discrimination of MDEA from common adulterants such as caffeine, paracetamol, glucose and other ATS (amphetamine - A, methamphetamine - MA, 3,4-methylenedioxyamphetamine - MDA), except 3,4-methylenedioxymethamphetamine (MDMA). In addition, MDEA screening was carried out on drugs seized by the Civil Police-DF, and the results compared with those obtained by HPLC-MS. The developed method is fast, simple, pratical, portable and low cost, being promising for applications in forensic chemistry.CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorCNPq - Conselho Nacional de Desenvolvimento Científico e TecnológicoFAPEMIG - Fundação de Amparo a Pesquisa do Estado de Minas GeraisDissertação (Mestrado)A produção e consumo de drogas sintéticas conhecidas como Novas Substâncias Psicoativas vêm aumentando a cada ano e derivados de anfetaminas como o 3,4-metilenodioxietilanfetamina (MDEA) têm sido apreendidos. Deste modo, o desenvolvimento de métodos analíticos rápidos, simples e portáteis para a triagem dessas substâncias em drogas apreendidas é de suma importância. Este trabalho apresenta um método de triagem de MDEA em drogas empregando eletrodo impresso de carbono comercial (Dropsens®) e voltametria de onda quadrada (SWV). Inicialmente foi estudado o comportamento eletroquímico por voltametria cíclica em tampão Britton-Robinson 0,04 mol L-1 em distintos pHs (2 a 12), no qual foram propostos mecanismos eletroquímicos para os processos observados. Entretanto, foi escolhido o pH 3 considerando melhor detectabilidade e maior número de picos identificáveis (Epa1 = + 0,21 V, Epa2 = + 0,87 V e Epc1 = + 0,15 V). Posteriormente, a detecção do MDEA foi realizada por SWV devido à maior sensibilidade e rapidez da técnica. Empregando as condições otimizadas (amplitude de 40 mV, frequência de 30 Hz e incremento de potencial de 4 mV) foram obtidos os seguintes parâmetros analíticos para o pico 1 (Ep1 = 0,16 V) e pico 2 (Ep2 = 0,77 V), respectivamente: faixa linear de 5,0 a 50,0 µmol L-1 (R2 > 0,99), sensibilidades de 0,22 e 0,14 µA/mol L-1 e limites de detecção de 0,07 e 0,11 µmol L-1. A precisão do método foi satisfatória, devido aos baixos desvios padrão relativos (DPR) obtidos na repetibilidade (P1: DPR < 6 %; P2: DPR < 10 %; n = 10). A reprodutibilidade inter-eletrodo (n = 5) foi baixa em termos de corrente de pico (DPR < 35,4 %), porém alta considerando os potenciais de pico (DPR < 2,3 %). No estudo de interferentes, foi verificada a discriminação de MDEA na presença de adulterantes como cafeína, paracetamol, glicose e outras substâncias estimulantes do grupo das anfetaminas (anfetamina - A, metanfetamina - MA e 3,4-metilenodioxianfetamina - MDA), exceto 3,4-metilenodioxi-metanfetamina (MDMA). A triagem de MDEA foi realizada em drogas apreendidas pela Polícia Civil-DF, sendo os resultados comparados com os obtidos pelo método de HPLC-MS. O método desenvolvido é rápido, simples, prático, portátil e de baixo custo, sendo promissor para aplicações na química forense.