Electrospray-mass spectrometric studies of selectivity of alkali metal cations extraction by calix[4]arene crowns

Electrospray Ionization Mass Spectrometry (ESI/MS) has quickly become a versatile method of qualitative analysis of a wide variety of host–guest complexes formed in solution. However, considerable controversy exists on how ESI spectra quantitatively reflect and compare to the results obtained on these complexes. The extraction of alkali cations from acidic aqueous solutions by nine various calix[4]arenes-crown-6 diluted in NPOE, was studied by using ESI/MS. The stoichiometry of cesium complex and Cs+/Na+selectivity were evaluated.

METASTABLE DECAY OF MERCURY/CESIUM COMPLEX CLUSTER

Metastable decay of mercury/cesium complex cluster, Hg n Cs +, was measured by using a time-of-flight mass spectrometer of Osaka University. The TOF spectrometer is comprised of four electrostatic analyzers (ESAs). By scanning the applied voltage of the ESAs, MS/MS spectra and MS/MS/MS spectra can be obtained. The product-ion spectra generated from metastable decay of the complex cluster were obtained by MS/MS analysis. The product ions of the decay were determined as Cs+ and Hg n Cs +. Sequential decays were also observed with the MS/MS/MS analysis mode of the spectrometer. The position occurring metastable decay producing detected ion can be selected with the TOF spectrometer. To compare the product-ion yield generated at two different positions, the rate constant of the decay can be estimated. In preliminary experiments using glycerin-trimer ion, [3g+H]+, as a precursor, the obtained rate constant of the decay is 2.0×104 l/s.