Determination of validamycin a residues in soil by precolumn derivatization and capillary gas chromatography

A method was developed for pre-column derivatization and gas chromatographic analysis of validamycin A residue in soil. Validamycin A was vibrating extracted from 10 g soil samples with 40 ml 10% ammonia solution for 60 minutes without additional clean-up step and then was derivatized with N,O-bis (trimethylsilyl) acetamide. Derivative of validamycin A was analyzed by gas chromatography with flame ionization detector (FID) on a capillary column, the temperature of inlet and detector were 240 degrees C and 280 degrees C respectively. It showed good linearity in the range of 4.4 - 71.0 mg/L (r = 0.9983). The average recoveries were 94.76% - 101.59% with the relative standard deviations of 1.1% - 2.9%. The limit of detection of validamycin A in soil was 0.2 mg/kg.