Novel experimental arrangement developed for direct fullerene analysis by electrospray time‐of‐flight mass spectrometry

Abstract

A novel electrospray setup was found effective for direct analysis of fullerene solutions by electrospray (ES) mass spectrometry. The electrospray capillary needle used for the analysis is equipped with a thin metal (copper, platinum or stainless steel) wire installed inside the capillary. The wire tip protrudes slightly from the capillary end. In this configuration the high electrical field formed by the wire tip stimulates a specific electrospray mode with a fine spray originating from the tip. The correlation of the acquired mass spectra with the magnified view of the spray at the capillary tip was investigated. The effective formation of fullerene ions in both negative and positive ion modes was observed in mass spectra only in the specific case of the electrospray originating from the wire tip. The fullerene di-anions observed in the negative ES mass spectra provide evidence for the electrochemical nature of this process occurring at the ES capillary tip. Observation of fullerene ions in mass spectra obtained using the suggested electrospray arrangement is assumed to be a consequence of the fine spray originating from the sharp metal wire tip. In this case the liquid/metal interface is near the Taylor cone apex.

Mass Spectrometry Studies of the Retro-Cycloaddition Reaction of Pyrrolidino and 2-Pyrazolinofullerene Derivatives Under Negative ESI Conditions

“…Although the spectrometric fragments formed in the oxidation reactions of some fluorinated fullerenes have been observed under EI conditions [14], fullerenes and their functionalized derivatives are mainly analyzed under LDI and ESI conditions. The electrochemical properties of fullerene derivatives permit the analysis of these molecules under ESI conditions and sometimes the formation of odd-electron molecular ions [15,16].…”

Competitive retro‐cycloaddition reactions in heterocyclic fullerene bis‐adducts ions: selective removal of the heterocyclic moieties

“…Although matrix‐assisted laser desorption/ionization (MALDI) and electrospray ionization (ESI) are the most frequently used ionization methods for the analysis of fullerenes, new techniques such as atmospheric pressure photoionization (APPI) have also been successfully employed for the characterization of these carbon allotropes and their derivatives . The electrochemical nature of the ESI process was used for the direct analysis of fullerene solutions providing evidence of the process occurring at the ES capillary tip . On the other hand, the ion sources of electron impact (EI) and laser desorption/ionization (LDI) spectrometers have been used to study the reaction of C 60 with aromatic compounds .…”

Atmospheric Pressure Photoionization Mass Spectrometry of Fullerenes

“…However, these isotope patterns did not match those obtained with 278 ESI and APCI or with the theoretical ones, showing higher than expected relative abundances of 279 m/z M, M+1, M+2 and M+3 for all the studied compounds. 11,19 eV. This suggests that in addition to 13 C, another ion contributed to the relative abundance of 294…”

“…7,8 85 Although liquid chromatography (LC) with UV detection has been proposed for the 86 analysis of fullerenes, [9][10][11][12][13][14] liquid chromatography-mass spectrometry (LC-MS) is the most 87 commonly used technique nowadays for the determination and characterization of fullerenes and 88 substituted fullerenes in complex matrices. 11,[15][16][17][18][19][20][21][22][23] Most of these studies have mainly dealt with the 89 separation and determination of C 60 and C 70 fullerenes or some of the C 60 -substituted fullerenes. 10-…”

“…For the LC-MS analysis of these compounds, both 92 electrospray ionization (ESI) 17,19,20,23,24 and atmospheric pressure chemical ionization 93 (APCI) 11,15,16,18,21,22 have been used as ionization sources. 94…”