A method was developed using matrix solid-phase dispersion (MSPD), together with gas chromatography coupled to mass spectrometry (GC-MS) for determination of ametryn, tetraconazole, flumetralin, tebuconazole, pyrimethanil, dichlofluanid and kresoxim-methyl in dehydrated Hyptis pectinata (sambacaitá) medicinal plant material. The evaluated parameters included the type and amount of sorbent (C18, neutral alumina, silica gel and Florisil) and the nature of the eluent (dichloromethane, ethyl acetate and dichloromethane:ethyl acetate (1:1, v/v)). The best results were obtained using 0.5 g of plant material, 0.5 g of C18 as sorbent and dichloromethane (20 mL) as the eluting solvent. The method was validated using plant samples spiked with pesticides at different concentration levels (0.05-1.0 µg g-1). Average recoveries (using four replicates) ranged from 83 to 127%, with relative standard deviations between 4 and 15%. Limits of detection (LOD) and quantification (LOQ) were in the ranges 0.02-0.07 µg g-1 and 0.05-0.1 µg g-1, respectively.
Hyptis pectinata; matrix solid-phase dispersion; medicinal plant; sambacaitá; pesticides
