Application of multiwalled carbon nanotubes for solid-phase extraction of organophosphate pesticide

Multiwalled carbon nanotube (MWCNT) was developed as a new sorbent for solid-phase extraction (SPE) of organophosphate (OP) pesticides. A combination of SPE with square-wave voltammetric (SWV) analysis resulted in a fast, sensitive, and selective electrochemical method for determination of OP pesticide using methyl parathion (MP) as a representative. Because of the strong affinity of MWCNT for phosphoric group, nitroaromatic OP compounds can strongly bind to the MWCNT surface. The macroporosity and heterogeneity of MWCNT allow extracting a large amount of MP less than 5 min. The stripping response was highly linear over the MP range of 0.05–2.0 μg/mL, with a detection limit of 0.005 μg/mL. The determination of MP in garlic samples showed acceptable accuracy. The fast extraction ability of MWCNT makes it promising sorbent for various solid-phase extractions.