Extraction and high-performance liquid chromatographic analysis of C60, C70, and [6,6]-phenyl C61-butyric acid methyl ester in synthetic and natural waters

Studies have shown that C60 fullerene can form stable colloidal suspensions in water that result in C60 aqueous concentrations many orders of magnitude above C60's aqueous solubility; however, quantitative methods for the analysis of C60 and other fullerenes in environmental media are scarce. Using a 80/20 v/v toluene–acetonitrile mobile phase and a 4.6 mm × 150 mm Cosmosil 5 μ PYE column, C60, C70, and PCBM ([6,6]-phenyl C61-butyric acid methyl ester) were fully resolved. Selectivity factors (α) for C60 relative to PCBM and C70 relative to C60 were 3.18 and 2.19, respectively. The best analytical wavelengths for the fullerenes were determined to be 330, 333, and 333 nm with log molar absorption coefficients (log ɛ) of 4.63, 4.82, and 4.60 for PCBM, C60, C70, respectively. Extraction and quantitation of all three fullerenes in aqueous suspensions over a range of pH (4–10) and ionic strengths were very good. Whole-method quantification limits for ground and surface suspensions were 2.87, 2.48, and 6.54 μg/L for PCBM, C60, and C70, respectively.