Electrospray ionization mass spectrometry (ESI-MS) is found to gently and efficiently transfer small to large as well as singly to multiply charged [X+]n[A-]m supramolecules of imidazolium ion (X+) ionic liquids to the gas phase, and to reveal "magic numbers" for their most favored assemblies. Tandem mass spectrometric experiments (ESI-MS/MS) were then used to dissociate, via low-energy collision activation, mixed and loosely bonded [A- - - -X- - - -A']- and [X- - - -A- - - -X']+ gaseous supramolecules, as well as their higher homologues, and to estimate and order via Cooks' kinetic method (CKM) and B3LYP/6-311G(d,p) calculations the intrinsic solvent-free magnitude of hydrogen bonds. For the five anions studied, the relative order of intrinsic hydrogen-bond strengths to the 1-n-butyl-3-methylimidazolium ion [X1]+ is: CF3CO2- (zero) > BF4- (-3.1) > PF6- (-10.0) > InCl4- (-16.4) and BPh4- (-17.6 kcal mol(-1)). The relative hydrogen-bond strength for InCl4- was measured via CKM whereas those for the other anions were calculated and used as CKM references. A good correlation coefficient (R=0.998) between fragment ion ratios and calculated hydrogen-bond strengths and an effective temperature (Teff) of 430 K demonstrate the CKM reliability for measuring hydrogen-bond strengths in gaseous ionic liquid supramolecules. Using CKM and Teff of 430 K, the intrinsic hydrogen-bond strengths of BF4- for the three cations investigated is: 1-n-butyl-3-methyl-imidazolium ion (0) > 1,3-di-[(R)-3-methyl-2-butyl]-imidazolium ion (-2.4) > 1,3-di-[(R)-alpha-methylbenzyl]-imidazolium ion (-3.0 kcal mol(-1)). As evidenced by "magic" numbers, greater stabilities are found for the [(X1)2(BF4)3]- and [(X1)5A4]+ supramolecules (A not equal InCl4-).

Rapid quantitative enantiomeric analysis of mannose, glucose, galactose, and ribose is achieved using electrospray ionization and cluster ion dissociation with data analysis by the kinetic method. Several modified amino acids (N-Ac-L-Phe, N-benzoyl-L-Phe, N-t-Boc-L-Phe, N-Ac-L-Pro, N-t-Boc-L-Pro, N-Fmoc-L-Pro, N-Ac-L-Tyr, O-Me-L-Tyr) and four transition divalent metal cations (Co2+, Cu2+, Ni2+, and Zn2+) were tested to select the best system for chiral recognition and quantitation of each sugar. Quantitative determinations of the enantiomeric compositions of sugar solutions were achieved using either multiple- or two-point calibration curves; differences between the actual and experimental values were <2% enantiomeric excess (ee).

High performance liquid chromatography (HPLC), ultraviolet spectroscopy (UV), and total organic carbon (TOC) analyses show that caffeine is quickly and completely degraded underthe oxidative conditions of the UV/H2O2,TiO2/ UV, and Fenton systems but that the organic carbon content of the solution decreases much more slowly. Continuous on-line and real-time monitoring by electrospray ionization mass (ESI-MS) and tandem mass spectrometric experiments (ESI-MS/MS) as well as high accuracy MS measurements and gas chromatography-mass spectrometry analysis show that caffeine is first oxidized to N-dimethylparabanic acid likely via initial OH insertion to the C4=C8 caffeine double bond. A second degradation intermediate, di(N-hidroxymethyl)parabanic acid, has been identified by ESI-MS and characterized by ESI-MS/MS and high accuracy mass measurements. This polar and likely relatively unstable compound, which is not detected by off-line GC-MS analysis, is likely formed via further oxidation of N-dimethylparabanic acid at both of its N-methyl groups and constitutes an unprecedented intermediate in the degradation of caffeine.