Analysis of C60-fullerene derivatives and pristine fullerenes in environmental samples by ultrahigh performance liquid chromatography–atmospheric pressure photoionization-mass spectrometry

•UHPLC–APPI-MS(/MS) analysis of pristine fullerenes and C60-derivatives is proposed.•Polar organic solvents affect retention time of fullerenes due to their aggregation.•In contrast to pristine fullerenes, C60-derivatives show fragmentation in MS/MS.•Presence of C60 derivatives in sediments and waters is reported for the first time.

In this work, a method is proposed for the simultaneous analysis of several pristine fullerenes (C60, C70, C76, C78, and C84) and three C60-fullerene derivatives (N-methyl fulleropyrrolidine, [6,6]-phenyl C61 butyric acid methyl ester and [6,6]-phenyl C61 butyric acid butyl ester) in environmental samples. The method involves the use of ultrahigh performance liquid chromatography coupled to atmospheric pressure photoionization mass spectrometry (UHPLC–APPI-MS) and allowed the chromatographic separation in less than 4.5 min. The product ions from tandem mass spectrometry studies of fullerene derivatives were characterized and the most abundant one (m/z 720), corresponding to [C60]−, was selected for quantitation. Selected reaction monitoring (SRM at 0.7 m/z FWHM) by acquiring two transitions using both isotopic cluster ions [M]− and [M+1]− as precursor ions was proposed for quantitation and confirmation purposes. For pristine fullerenes, highly selective selected ion monitoring (H-SIM) acquisition mode by monitoring the isotopic cluster ions [M]− and [M+1]− was used. Pressurized solvent extraction conditions were optimized in order to improve recoveries of the studied fullerene compounds from sediment samples. Values up to 87–92% for C60-fullerene derivatives and lower but still acceptable, 70–80%, for pristine fullerenes were obtained. Method limits of quantitation (MLOQs) ranging from 1.5 pg L−1 to 5.5 ng L−1 in water samples and from 0.1 ng kg−1 to 523 ng kg−1 in sediments were obtained with good precision (relative standard deviations always lower than 13%). The applicability of the developed method was evaluated by analyzing several environmental samples such as sediments and pond water and the detected levels for C60-fullerene derivatives were of 0.1–2.7 ng kg−1 and 1.5–8.5 pg L−1, respectively. C60 and C70 were the only pristine fullerenes detected in the analyzed samples (0.1–7.2 ng kg−1 in sediments and 9–330 pg L−1 in water pond samples).