Competitive immobilization of multiple component chlorinated solvents by cyclodextrin derivatives

Immobilization of chlorinated solvents with hydropropyl and methyl cyclodextrins (CDs) was observed by head-space analysis to obtain the stability constants in single and multiple component systems. In each single component system, the highest stability constant was 0.299 mM−1 for perchloroethylene (PCE) by methyl-β-cyclodextrin (M-β-CD), 0.136 mM−1 for trichloroethylene (TCE) by M-β-CD, 0.106 mM−1 for cis-dichloroethylene (cis-DCE) by hydropropyl-α-cyclodextrin, and 0.090 mM−1 for trans-dichloroethylene (trans-DCE) by M-β-CD. When HP-β-CD and M-β-CD were used, the stability constants of PCE and TCE increased and those of DCEs decreased in a multiple component system. Differences in stability constants of single and multiple component systems thus should be important parameters when cyclodextrins are applied to solubilization of multiple chlorinated solvents.