EXTRAÇÃO EM FASE SÓLIDA DE RESÍDUOS DE AGROTÓXICOS DE ÁGUA SUPERFICIAL, EMPREGANDO UM SORVENTE DE MENOR RETENÇÃO

• Main Authors: Carlos A. S. Aguiar Júnior, Nadja T. M. Silva, Dayane F. Soares, Anizio M. Faria
• Format: Article
• Language: English
• Published: Sociedade Brasileira de Química
• Series: Química Nova
• Subjects: solid phase extraction; low retention sorbent; surfacewater, pesticides, HPLC-UV, method validation
• Online Access: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-40422018000600641&lng=en&tlng=en

Solid phase extraction (SPE) is one of the main sample preparation techniques. However, the cost of cartridges and the strong retention of hydrophobic compounds in traditional solid phases are limiting factors for their use. This paper describes the application of lab-made SPE cartridges with low retention material as solid phase, Si(PDAS) - poly(dimethyl-co-alkylmethylsiloxane) thermally immobilized on silica, in the determination of pesticide residues in surface water samples. The extraction method of three pesticides: carbendazim, diurom and methyl parathion in water samples was developed, optimized and validated using Si(PDAS) cartridges and HPLC-UV for quantification. The optimized method required a small organic solvent volume for the elution of pesticides from Si(PDAS), producing a concentration factor of 1000 times and allowing limits of detection like those obtained with hyphenated techniques. The validated method for extraction of pesticides in water samples presented: accuracy, with pesticide recoveries between 70-110%; precision, with RSD < 20%, and; high detectability, resulting in LOQ < 0.4 µg L-1 for all compounds. Si(PDAS) cartridges showed similar efficiency to those commercial C18 for the extraction of pesticides in surface water samples, with additional advantages such as ease, simplicity and low cost of preparation, up to six times cheaper than commercial cartridges.