The oxidative reactivity of THF derivatives formed during THF/nC 60 synthesis was evaluated with indigo dye as a model compound. The results showed that the formation of previously undetected oxidizing agents during THF/nC 60 synthesis accounted for the degradation of indigo dye by THF/nC 60 (THF/nC 60/unwashed), while THF/nC 60 after vigorous washing (THF/ nC 60/washed) and nC 60 prepared without the use of THFwere not reactive. γ-Butyrolactone (GBL) was detected by GC-MS in the THF/nC 60/unwashed as one of THF derivatives, but showed no reactivity with indigo dye. An organic peroxide was detected in the THF/nC 60/unwashed by HPLC,and was reactive with indigo dye. This compound was found to also account for the elevated antibacterial and bactericidal activities of THF/ nC 60/unwashed on E. coli. Analysis by LC/(+ESI)MS and 1H NMR showed that the detected THF peroxide was tetrahydro-2-(tetrahydrofuran-2- ylperoxy)furan. The formation of THF peroxide during the preparation of aqueous stable C 60 aggregates provides another potential explanation for the reactivity and oxidative stress mechanisms of THF/nC 60 system reported in the literature, although it does not exclude the potential reactivity and toxicity of nC 60 itself.
ASJC Scopus subject areas
- Environmental Chemistry