This study was conducted to evaluate desorption efficiencies by type: of desorption solvent for polar and non-polar organic compounds collected on activated charcoal tubes.
Analyses tested were toluene, m-xylene, isobutyl alcohol, n-butyl alcohol, cellosolve acetate, and butyl cellosolve. Three different concentration levels of spiked sample were made.
Types of cosolvent mixed with the main solvent, CS₂, were methanol, pentanol, and dimethylformamide (DMF) and the cosolvent for methylenechloride was methanol. The amounts of cosolvent added to the main solvent were 1, 5, and 10% by volume (v/v%), respectively.
The results were as follows:
1. For all mixed solvems except 1 % methanol and 1 % pentanol with CS₂, desorption efficiency significantly increased, compared with that of CS₂ alone.
2. Desorption efficiency increased by increasing analyse loading on charcoal tube regardless of mixed solvents used and the material polarity.
3. For all cosolvents mixed with CS₂ by 1% and 5% volume, desorption efficiency for non-polar compound was significantly higher than that of polar compound. For the 10% mixed solvents and the methylenechloride mixed with methanol, the results were opposite.
4. The lowest mean percent bias of 4.79% was obtained from the 5% DMF-CS₂ mixed solvent, followed by 4.82% from the 10% UMF-CS₂ solvent white the highest bias of 23.26% was from the solvent of CS₂ alone.
Based on the results of this study, in order to increase desorption efficiency, it is recommended to add such cosolvents as methanol, pentanol, and DMF to CS₂, preferably 5% by volume for analyzing polar compounds collected in charcoal tubes.
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