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Without performing any charge transfer chemical reaction, Cso and its derivatives could be analyzed directly by electrospray mass spectrometry. Oxidation or reduction at the metallsolution interface of the probe tip was probably responsible for the formation of these radical cations and anions. This technique appeared to be superior to desorption chemical ionization and fast-atom bombardment ionization in the analysis of Cso derivatives because the mass spectra were characterized by molecular ions with little or no fragmentation.Since its discovery in 1985,' Cm has been one of the most intensively studied molecules in organic and organometallic chemistry; many Cm derived molecules, including those with great potential in material science and medicine, have been synthesized. Mass spectrometry has played a key role not only in the discovery but also in the characterization of Cm.' A variety of ionization techniques such as electron impact (EI), chemical ionization, desorption chemical ionization (DCI), fast-atom bombardment (FAB), and laser desorption have all been used to characterize Cm and its derivative^.^-^ The analysis of Cm derivatives appears to be much more difficult than analysis of Cm itself; many Cm related compounds degrade easily under most ionization conditions. Therefore, the observation of ions with m/z values different from those of the expected analytes could be the result of either incomplete purification or degradation under ionization. An ideal ionization technique would be one that produced only the molecular and/or pseudomolecular ions, with little or no fragmentation. The structure of the sample can then be further investigated by collision-induced dissociation of the molecular ions.Electrospray ionization (ESI) has been one of the major foci of mass spectrometry in the past few years. This technique is known for giving 'soft' ionization and for its ability to analyze biopolymers. Unfortunately, not all types of compounds can be analyzed by ESI. In ESI, electrical energy is used to assist the transfer of ions initially present in solution into the gas phase at atmospheric pressure for mass spectrometric analysis. Therefore, compounds that are ionic or that can be ionized through acid-base reactions in solution are most suitable for ESI analysis. To expand the utility of ESI to so called 'ESI-inactive' compounds, chemical derivatization has received considerable attention as a useful approach for converting ESI-inactive compounds to ESI-active analytes. lo, Fullerenes are neutral and non-polar molecules and therefore are considered not amenable to ESI. Several approaches, including tagging C,, with crown a m i n a t i~n , '~ and oxidation-reduction in solution with chemical reagents,l5-l7 have all been used for making these compounds suitable for analysis by ESI. In this paper, results are presented to show that C,, and related derivatives can be analyzed directly by ESI-MS, without any requirement for pre-ionization in solution.* Author for correspondence. (635-pm 0.d.) stainless-steel tubi...

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Calocedimers A, B, C, and D, together with four known compounds, platydiol, alpha-cadinol, ferrugiol, and 6,7-dehydroferrugiol, were isolated from the bark of Calocedrus macrolepis var. formosana. Calocedimers A, B, C, and D are the dimers of abietane-O-camphane, abietane-O-cadinane, abietane-O-abietane, and abietane-O-abietane, respectively. Their structures were elucidated from spectroscopic data.