Analysis of a new herbicide (pyribenzoxim) residues in soil using direct-extract-injection HPLC with column switching

A simple and efficient analysis method of the herbicide residues in soil ha s been developed and applied to residual analysis of a new herbicide, pyrib enzoxim. Extraction and separation were performed in sequential mode by on- line column switching. On-line analysis shows better specificity than off-l ine analysis does. The analyte was well separated without interference and baseline distortion. Recovery yields for standard spiking were 97.9 +/- (S.D.) and 92.1 +/- 4 (S .D.) % at the concentration of 0.04 and 0.1. ppm in soil, respectively (n=3 ). The correlation coefficient was greater than 0.999 over the range betwee n 0.1 and 10/mL. The on-line solid phase extraction (SPE) analysis is descr ibed, as compared to offline SPE analysis.