Protonated Water Clusters / Eigen Cation / Zundel Cation / 1 H NMRIn a previous publication by Kalish et al. (J. Phys. Chem. A 115 (2011) 4063) the existence of well defined small protonated water clusters in acetonitrile has been established by IR spectroscopy. Here we report on a 1 H NMR study of triflic acid, CF 3 SO 3 H, in acetonitrile-water solutions. Using NMR we are able to corroborate the general solvation scheme we have proposed for the hydrated proton in acetonitrile as a function of the molar ratio between the strong mineral acid and water, n = [H 2 O]/[acid]. According to this scheme, backed now by both IR absorption spectroscopy and NMR measurements, the very strong triflic acid completely dissociates in acetonitrile/water solutions to yield the aqueous proton and the triflate anion when n > 1. Furthermore, increasing n results in the proton solvated in increasingly larger water clusters formed within the acetonitrile solution.Clearly distinguishable by NMR are the smallest protonated water clusters, the protonated water monomer, H + 3 O, and the protonated water dimer, H + 5 O 2 , which dominate the solution for n = 1,2,3. For larger n the NMR study indicates the gradual increase of the average protonated water cluster size as a function of n while the proton inner solvation core more closely retaining the characteristics of a deformed protonated water dimer, (H 2 O-H + · · ·OH 2 ) s than that of the protonated water monomer (H + 3 O) s .

An ETAAS method was developed to determine the platinum group elements and gold in copper-nickel ores using a single sample. It is based on an approach involving interconnected consideration of the main components of analytical procedure (autoclave decomposition of sample; collective extractive preconcentration of metals with a mixture of alkylaniline hydrochloride and petroleum sulfides; and atomic absorption spectrometric analysis of the extract). The concentrations of elements determined in standard reference materials (lode and impregnation copper-nickel sulfide ores) were found to be in accordance with the certified values, within experimental error. The relative standard deviation varied between 2 and 17% at 0.05-10 mg kg-1 element concentrations. The determination limits were 0.001-0.06 mg kg-l for a 5 g sample and an extract volume of 5 ml.