Effects of solutes on the alcohol-stimulative taste of vodkas.

Quantitative analyses of chemical components and sensory tests were carried out on vodka samples to test for stimulative taste of ethanol. Proton nuclear magnetic resonance (H NMR) spectra of the vodkas were measured with 600 MHz NMR. The effects of salts on the alcohol-stimulative taste were investigated for 15% (v/v) EtOH-HO solution.

Dilute nitric or nitrous acid solution containing halide ions as effective media for pure gold dissolution.

The greatly enhanced oxidation ability of dilute aqueous nitric acid (0.10-2.0 mol L(-1)) containing bromide and iodide salts as well as chloride salts has been examined based on the dissolution kinetics of pure gold at 30-60 °C.

Synthesis and spectral studies of 2-[(N-ethyl carbazole)-3-sulfonyl ethylenediamine]-1-N,N-2-(2-methypyridy) as a fluorescence probe for Zn²⁺.

A novel Zn(2+) fluorescence probe, 2-[(N-ethyl carbazole)-3-sulfonyl ethylenediamine]-1-N,N-bis(2-methypyrbidy), was designed and synthesized via simple steps, and its structure was confirmed by IR and (1)H NMR. The probe gives significant fluorescence enhancement immediately following Zn(2+) addition at neutral pH and exhibits improved selectivity for Zn(2+) compared to the other metal ions in aqueous solution. The spectra and fluorescence quantum yield of the synthesized compound were carefully investigated by UV-vis absorption and fluorescence spectra in various solvents.

UV-visible and 1H or 13C NMR spectroscopic studies on the specific interaction between lithium ions and the anion from tropolone or 4-isopropyltropolone (hinokitiol) and on the formation of protonated tropolones in acetonitrile or other solvents.

The specific interaction between lithium ions and the tropolonate ion (C(7)H(5)O(2)-: L-) was examined by means of UV-visible and 1H or 13C NMR spectroscopy in acetonitrile and other solvents. On the basis of the electronic spectra, we can propose the formation of not only coordination-type species (Li+(L-)2) and the ion pair (Li+L-) but also a "triple cation" ((Li+)2L-) in acetonitrile and acetone; however, no "triple cation" was found in N,N-dimethylformamide (DMF) and in dimethylsulfoxide (DMSO), solvents of higher donicities and only ion pair formation between Li+ and L- in methanol of much higher donicity and acceptivity. The 1H NMR chemical shifts of the tropolonate ion with increasing Li+ concentration verified the formation of (Li+)2L- species in CD3CN and acetone-d6, but not in DMF-d6 or CD(3)OD.

Hydrogen bonding of water-ethanol in alcoholic beverages.

An alcoholic beverage is a type of water-ethanol solution with flavor and taste. The properties of the hydrogen bonding of water-ethanol in alcoholic beverages have not been clarified sufficiently. We investigated factors that could affect the hydrogen-bonding structure of water-ethanol on the basis of proton nuclear magnetic resonance (1H NMR) chemical shifts of the OH of water-ethanol and Raman OH stretching spectra.

Proton nuclear magnetic resonance and Raman spectroscopic studies of Japanese sake, an alcoholic beverage.

The hydrogen-bonding property of water--ethanol in Japanese sake, a kind of brewage, was examined on the basis of both (1)H NMR chemical shifts of the OH of water--ethanol and the Raman OH stretching spectra. In 20% (v/v) EtOH-H(2)O solution, amino acids as well as organic acids caused low-field chemical shifts, i.e.

Hydrogen bonding in alcoholic beverages (distilled spirits) and water-ethanol mixtures.

The hydrogen-bonding properties of water-ethanol of alcoholic beverages and water-ethanol mixtures of the corresponding ethanol contents were examined on the basis of OH proton NMR chemical shifts and the Raman OH stretching spectra of water and ethanol. Japanese shochu, an unaged distilled spirit of 25% (v/v) alcoholic content made from various grains, was provided for the samples; it is a high-purity spirit as it contains only small amounts of dissolved components, like typical vodka, gin, and white rum. The hydrogen-bonding structure in shochu containing some acids was found to be different from that of the water-ethanol mixture with corresponding ethanol content.

Solute effects on the interaction between water and ethanol in aged whiskey.

The hydrogen-bonding structure of water-ethanol in whiskey was examined on the basis of (1)H NMR chemical shifts of the OH of water and ethanol. Phenolic acids and aldehydes (gallic, vanillic, and syringic acids; vanillin and syringaldehyde) exhibited their structure-making effects regardless of the presence or absence of 0.1 or 0.

Contamination and biomethylation of organotin compounds in pearl/fish culture areas in Japan.

Uwakai of Japan is famous for pearl and yellowtail fish culture. Recently, pearl culture farming in that region has suffered from a low production of pearls. An illegal use of organotin antifouling paints on fishing nets was reported.