Determinação Voltamétrica do Repelente de Insetos DEET

The consumption of insect repellents has dramatically increasedin the last years mainly due to the appearing ofnew vector-borne diseases,such as dengue, ZikaandChikungunya.Consequently, an increase in the offer of different commercial repellents was also observed, requiring proper analytical methods to guarantee quality control of such products. N,N-Diethyl-m-toluamide, DEET, is the major component of most topically appliedconsumer insect repellents asasafe broad spectrum repellent, which provides complete protectionover a long period of time.1 Furthermore,due toits constant and direct discharge into natural waters,DEET is considered as a contaminant of emerging concern, being commonly detectedin water samples around the world.2Thisworkpresentsa voltammetric methodto the determinationof DEET based on square-wave voltammetryin different repellent brands and DEET levels. The voltammetric measurements were carried outin 10 mL of 0.1 mol L-1tetrabutylammonium perchloratein acetonitrile,usingglassy carbon asworking electrode, saturated calomelasreference electrode,and platinum as auxiliary electrode.The potential scan range was 0.0 V–2.5 V, step potential (∆Es) of 5mV, frequency of 25 Hz, and amplitude of20mV. The analytical curve waslinearin the DEET concentration range between0.99 and 4.76mmol L-1, and itis representedby the equation: I (μA) = -15.19(μA) + [16.00(μA L mmol-1) x C (DEET, mmol L-1)], R2 = 0.9807. The limits of detection (LOD) and quantification (LOQ) were 6.85 and 22.8μmol L-1, respectively.The methodwas satisfactoryapplied in the determination of DEET in different repellentsamples, with aminimumconcentration ofDEET in such products about 260mmol L-1,LOD and LOQ values obtained were within the linear range found for the chromatographic method, 30.5–26.0 μmol L-1,and indicate that this method could also be employed in the determination of traces of DEET in environmental samples such as residuary and potable waters.