Acid-induced cloud-point extraction coupled to spectrophotometry for the determination of carbaryl residues in waters and vegetables

A simple and rapid spectrophotometry for the determination of carbaryl based on acid-induced anionic surfactant micelle-mediated extraction (acid-induced cloud-point extraction) coupled to derivatization with 2-naphthylamine-1-sulfonic acid (ANSA) reagent has been demonstrated. Sodium dodecyl sulfate (SDS) and concentrated HCl were used as extractants at room temperature. ANSA derivatization was directly reacted with carbaryl without alkali hydrolysis. The optimum conditions for both acid-induced extraction and derivatization were investigated. The proposed method shows good analytical features with low detection limit (50 mu g L(-1)) as well as linearity covered a wide range up to 7.0 mg L(-1), good precision with the relative standard deviation of 2.3% (n = 10), and high recoveries in the samples (>85%). The high risks of carbaryl contamination in the local vegetable samples studied were observed with the level of 2.2 g kg(-1). The results of the proposed method were comparable to those obtained from HPLC (t-test. P=0.05). (C) 2008 Elsevier B.V. All rights reserved.