Determination of Residual Dalapon in Sugarcane by Gas Chromatograph Equipped with Electron Capture Detector (GC-ECD)
SU-HSIANG TSENG1,2, YU-JU LIN1, PI-CHIOU CHANG1, SHIN-SHOU CHOU1 AND HUNG-MIM CHANG2*
1.Bureau of Food and Drug Analysis, Department of Health, 161-2 Kunyang St., Nangang District, Taipei 115-13, Taiwan, R.O.C.
2.Graduate Institute of Food Science and Technology, National Taiwan University, Taipei 106-17, Taiwan, R.O.C.
(Received: February 12, 2004; Accepted: May 27, 2004)
ABSTRACT
A gas chromatographic method using an electron capture detector (GC-ECD) was developed for the determination of residual dalapon, esterified with methanol in sulfuric acid, in sugarcane. Dalapon in plant matrix was initially extracted with sulfuric acid solution, followed by partition extraction with diethyl ether in the presence of NaCl and esterification with 10% H2SO4 methanolic for GC-ECD analysis. Recovery of dalapon (0.05~0.20 ppm) spiked in sugarcane samples was carried out to obtain an average recovery of 89.7~109.4% with a coefficient of variation (CV) of 1.0~9.3% and a method detection limit (MDL) of 0.01 ppm. Peak of dalapon methyl ester was further identified by a GC-MS spectrum. The developed procedure was simple and the reagents used were slightly toxic, thus suitable for the accurate quantification of dalapon residues in crops.
Key words: pesticide, dalapon, esterification reaction, gas chromatography, electron capture detector