There are no Fullerenes in the K-T Boundary Layer

Characterization and liquid chromatography-MS/MS based quantification of hydroxylated fullerenes

Highly water-soluble hydroxylated fullerene derivatives are being investigated for a wide range of commercial products as well as for potential cytotoxicity. However, no analytical methods are currently available for their quantification at sub-ppm concentrations in environmental matrixes. Here, we report on the development and comparison of liquid chromatography-ultraviolet/visible spectroscopy (LC-UV/vis) and liquid chromatography-mass spectrometry (LC-MS) based detection and quantification methods for commercial fullerols. We achieved good separation efficiency using an amide-type hydrophilic interaction liquid chromatography (HILIC) column (plate number >2000) under isocratic conditions with 90% acetonitrile as the mobile phase. The method detection limits (MDLs) ranged from 42.8 ng/mL (UV detection) to 0.19 pg/mL (using MS with multiple reaction monitoring, MRM). Other MS measurement modes achieved MDLs of 125 pg/mL (single quad scan, Q1) and 1.5 pg/mL (multiple ion monitoring, MI). Each detection method exhibited a good linear response over several orders of magnitude. Moreover, we tested the robustness of these methods in the presence of Suvanee River fulvic acids (SRFA) as an example of organic matter commonly found in environmental water samples. While SRFA significantly interfered with UV- and Q1-based quantifications, the interference was relatively low using MI or MRM (relative error in presence of SRFA: 8.6% and 2.5%, respectively). This first report of a robust MS-based quantification method for modified fullerenes dissolved in water suggests the feasibility of implementing MS techniques more broadly for identification and quantification of fullerols and other water-soluble fullerene derivatives in environmental samples.

Quantitative analysis of fullerene nanomaterials in environmental systems: a critical review

The increasing production and use of fullerene nanomaterials has led to calls for more information regarding the potential impacts that releases of these materials may have on human and environmental health. Fullerene nanomaterials, which are comprised of both fullerenes and surface-functionalized fullerenes, are used in electronic, optic, medical, and cosmetic applications. Measuring fullerene nanomaterial concentrations in natural environments is difficult because they exhibit a duality of physical and chemical characteristics astheytransition from hydrophobic to polar forms upon exposure to water. In aqueous environments, this is expressed as their tendency to initially (i) self-assemble into aggregates of appreciable size and hydrophobicity, and subsequently (ii) interact with the surrounding water molecules and other chemical constituents in natural environments thereby acquiring negative surface charge. Fullerene nanomaterials may therefore deceive the application of any single analytical method that is applied with the assumption that fullerenes have but one defining characteristic (e.g., hydrophobicity). Our findings include the following: (1) Analytical procedures are needed to account for the potentially transitory nature of fullerenes in natural environments through the use of approaches that provide chemically explicit information including molecular weight and the number and identity of surface functional groups. (2) Sensitive and mass-selective detection, such as that offered by mass spectrometry when combined with optimized extraction procedures, offers the greatest potential to achieve this goal. (3) Significant improvements in analytical rigor would result from an increased availability of well characterized authentic standards, reference materials, and isotopically labeled internal standards. Finally, the benefits of quantitative and validated analytical methods for advancing the knowledge on fullerene occurrence, fate, and behavior are indicated.

Evaluation of Raman spectroscopy to detect fullerenes in geological materials

Fullerene C(60) was determined repeatedly from a few types of carbonaceous matter from geological environments. Detailed investigation of structural aspects of pure carbonaceous matrices as well as of their experimental mixtures with fullerene C(60) permits better understanding of the occurrence mode of fullerenes inside the network of natural samples. However, it appears that Raman microspectrometry is not competitive in the case of investigated current geological carbonaceous matrices with added fullerenes, when the concentration of fullerene C(60) is 100 ppm or lower. In such a situation, C(60) is highly dispersed and careful interpretation of the results of Raman microspectrometry does not permit us to obtain valuable quantitative structural data. Obtained sensitivity for detecting C(60) in investigated matrices was only 1%. Analytical reasons for these results are discussed.