Gas-phase postderivatization following solid-phase microextraction for determining acidic herbicides in water.
This study analyzes acidic herbicides from an aqueous sample by developing a methylated postderivatization on the fiber following solid-phase microextration (SPME) with diazomethane gas procedure combined with GC/MS. Analysis results indicate that a silica fiber coated with polyacrylate (PA) yields a higher extraction efficiency than that obtained with poly(dimethylsiloxane) (PDMS) using the SPME technique. Detection limits are achieved at the level of 10-30 ng/L. Linearity is obtained over a wide range, with precision below 12% RSD. In addition, the significant reduction in extraction efficiency is attributed to the concentration of humic acids exceeding 5 mg/L. Various degradation compounds of acidic herbicides in basic solution are also detected, including 2,4-dichlorophenol, 2,4,5-trichlorophenol, 4-chloro-3-methylphenol, pentachlorinated biphenyl, and tetrachlorinated biphenyl. Moreover, the amount of pentachlorinated biphenyl and tetrachlorinated biphenyl increases over time.
Lee
M R
MR
Department of Chemistry, National Chung-Hsing University, Taichung, Taiwan, R.O.C. mrlee@mail.nchu.edu.tw
Lee
R J
RJ
Lin
Y W
YW
Chen
C M
CM
Hwang
B H
BH
D008401:Gas Chromatography-Mass Spectrometry; D006540:Herbicides / Q000032:analysis* / Q000737:chemistry; D007202:Indicators and Reagents; D014874:Water Pollutants, Chemical / Q000032:analysis*; D014881:Water Supply / Q000032:analysis*
D006540:Herbicides; D007202:Indicators and Reagents; D014874:Water Pollutants, Chemical