Otimização de um método de extração ultra-sônica e análise por CLAE para determinação de Diuron e seus metabólitos em solo de cultivo de cana-de-açúcar.

Abstract

Diuron, N-(3,4-dichlorophenyl)-N, N-dimethylurea can be transformed into the soil through the biodegradation of 3-(3,4-dichlorophenyl)-3-methylurea (DCPMU), 3.4-diclorofenilureia (DCPU) and 3,4-dichloroaniline (DCA). This study aimed to optimize and validate a method of extraction and analysis of these substances in the soil by HPLC/DAD. There was extracted with methanol in the bath ultrasonic and analysis in a liquid chromatograph/detector brand Waters. The condition of analysis optimized for separation of analytes was mobile phase methanol: water 50:50 (v / v), flow 1 mL min^-1. Wavelength of 240 nm was selected for the DCA and 254 nm for diuron, DCPMU and DCPU. It was used column and pre column Waters Xterra RP18, 5 um, 4.6 and 3.9 x 150 mm x 20 mm. The calibration curve was obtained from the fortification of the soil with the mixture of patterns in the range of 5 mg Kg^-1 to 200 mg Kg^-1 of soil. The recovery was obtained in two concentration levels of 5 and 200 mg. Kg^-1 of soil was between 85 and 99%. The repeatability was 0.78%, 2.20%, 2.17% and 1.72% and intermediate precision was 2.48%, 2.11%, 3.10% and 2.77% for diuron, DCPMU, DCPU and DCA, respectively. The limit of quantification was 1.25 mg Kg^-1 soil. The concentration of diuron found in some bioaugmented soil samples ranged from 5.5 to 8.9 mg Kg^-1 soil, but was not detected the presence of their metabolites.