Synthesis of tannic acid azo polyurethane sorbent and its application for extraction and determination of atrazine and prometryn pesticides in foods and water samples

Abstract

A new inexpensive sorbent (PUF–azo–Tan) was prepared by the coupling of tannic acid with polyurethane foam. The PUF–azo–Tan was characterized using different tools. Two new bands at 1724.1 and 1596.8 cm−1 assigned for CO and NN groups appeared in the IR spectrum of PUF–azo–Tan. The PUF–azo–Tan contains 0.95 and 0.15 mmol g−1 of phenolic and carboxylic groups, respectively. The pHZPC value of PUF–azo–Tan is 6.4. The PUF–azo–Tan has a considerable stability toward acid, alkali, and organic solvents. Atrazine and prometryn pesticides were extracted and preconcentrate by PUF–azo–Tan column and then analyzed by gas chromatography (GC) coupled with mass spectrometry. The effects of different parameters including pH, sample volume, temperature, initial concentration of pesticides, and shacking time were studied to optimize the presented procedure. The sorption capacity of PUF–azo–Tan was 0.14 mmol g−1 (32 mg g−1) and the extraction of the pesticides was accomplished within 3–5 min. Kinetics studies data fitted the pseudo-second-order model (R2 = 0.989). The average detection limit of triazine pesticides in solution was 0.6 ng mL−1 (RSD = 0.35%, n = 3). The equilibrium process was well described by the Freundlich isotherm model (R2 = 0.993). The extraction of the tested pesticides was accomplished in a period range 3–5 min. The proposal study reveals PUF–azo–Tan has the potential of application as an efficient sorbent for the extraction and preconcentration of pesticides in cucumber, guava and potato foods, and water samples.