Determination of chlorophenolics in waters by membrane solid-phase extraction: comparison between C-18 and activated carbon membranes and between modes of extraction and elution
Le. Sojo et J. Djauhari, Determination of chlorophenolics in waters by membrane solid-phase extraction: comparison between C-18 and activated carbon membranes and between modes of extraction and elution, J CHROMAT A, 840(1), 1999, pp. 21-30
Chlorophenols, chlorocatechols and chloroguaiacols were spiked at the 1 ppb
level into water samples containing up to 50 ppm dissolved organic carbon,
acetylated in situ and extracted onto C-18 and activated carbon (AC) membr
anes by dynamic or static sorption. Recovery of the analytes from the membr
anes was carried out by either static (in-vial elution) or dynamic desorpti
on (elution) using either acetone or toluene. Extracts were analysed by gas
chromatography-mass spectrometric detection (GC-MSD). C-18 membranes gave
recoveries of between 70 and 102% for all compounds with the exception of p
henol, when using dynamic desorption with acetone as the eluting solvent. S
tatic desorption using C-18 membranes gave satisfactory recoveries (65-80%)
for chlorophenols. AC membranes gave quantitative recoveries for all compo
unds when using dynamic desorption with toluene. Static desorption using AC
membranes:resulted in low recoveries (<60%) for all compounds except pheno
l. A combination of a C-18 membrane placed on top of the AC membrane during
dynamic extraction was tested to increase retention of phenol. Dynamic des
orption of both membranes in the reverse direction (AC on top of C-18) usin
g 10 mi of acetone or toluene gave quantitative results for all compounds,
even in the presence of 50 ppm dissolved organic carbon. (C) 1999 Elsevier
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