Determinação de LSD por Voltametria de Onda Quadrada em Eletrodo Quimicamente Modificado com Base de Schiff

LSD (lysergic acid diethylamide) is an illegal hallucinogenic drug commonly found in blotters and its consumption continues to rise in Latin America, especially in Colombia and Brazil, according to the World Drug Report of 2014. Despite of various studies in the electrochemical detection for seized drugs, like cocaine, there is a lack of voltammetric detection of LSD in the literature. It is important to highlight the specificity and selectivity obtained in this analytical technique through chemical modification in electrode surface. This study proposes a voltammetric methodology with chemically modified carbon paste electrode using a Schiff base complex, [UO2(Ac-ophen)]•H2O, for voltammetric detection of LSD. The experimental procedure was carried out mixing graphite powder, modifier and paraffin (40:20:40/m:m) for the composition of working electrode. We analyzed LSD by Square Wave Voltammetry, which is known by its high sensitivity. The use of an aqueous system for the analyses is an innovation, compared to methodologies reported in literature. For a potential range from -1.5 to 1.5 V in a scan rate of 10 mV s-1, there is an oxidation current peak related to a reaction between the complex and LSD. After optimization of all the experimental parameters (pre concentration time, frequency and amplitude), we constructed an analytical curve using the standard addition of LSD. The linear correlation coefficient was 0.990 and the values obtained for limits of detection and quantification were 0,69 *10-6 and 1,02 *10-6 mol L-1, respectively. In an assay applied in simulated seized samples (blotters), the recovery values were about 102%-108%. The present work allows a new application of Schiff Bases and is able to detect LSD in trace levels.