Development and validation of an alternative to conventional pretreatment methods for residue analysis of butachlor in water, soil, and rice.

ABSTRACT

A rapid and effective alternative analytical method for residues of butachlor in water, soil, and rice was established. The operating variables affecting performance of this method, including different extraction conditions and cleanup adsorbents, were evaluated. The determination of butachlor residues in soil, straw, rice hull, and husked rice was performed using GC/MS after extraction with n-hexane and cleanup with graphite carbon black. The average recoveries ranged from 81.5 to 102.7%, with RSDs of 0.6-7.7% for all of the matrixes investigated. The limits of quantitation were 0.05 mg/kg in water and rice plant, and 0.01 mg/kg in soil, straw, rice hull, and husked rice. A comparison among this proposed method, the conventional liquid-liquid extraction, the Quick, Easy, Cheap, Effective, Rugged, and Safe method, and Soxhlet extraction indicated that this method was more suitable for analyzing butachlor in rice samples. The further validation of the proposed method was carried out by Soxhlet extraction for the determination of butachlor residues in the husked rice samples, and the residue results showed there was no obvious difference obtained from these two methods. Samples from a rice field were found to contain butachlor residues below the maximum residue limits set by China (0.5 mg/kg) and Japan (0.1 mg/kg). The proposed method has a strong potential for application in routine screening and processing of large numbers of samples. This study developed a more effective alternative to the conventional analytical methods for analyzing butachlor residues in various matrixes.