Coupling constants ammonium compounds

Baranski and Lu [209] have carried out, applying microelectrodes, voltammetric studies on ammonium amalgam in propylene carbonate solutions at room temperatures. The sweep rates up to 80 V s were appropriate for the analysis of the formation kinetics of this compound. Experimental and numerical simulation results have shown that ammonium amalgam was formed via fast charge-transfer process and its first-order decomposition was characterized by the rate constant of about 0.6 s . Diffusion coefficient of NH4 radical in mercury was estimated to be about 1.8 X 10 cm s k The formal potential of NH4+ (aq)/NH4(Hg) couple was determined as—1.723 V (SHE). 

Capillary electrophoresis-ESI-MS (CE-ESI-MS) was proposed for identification and simultaneous quantification of several 5 -monophosphate ribonucleotides in infant formula samples [26], The BGE was a 30 mM ammonium formate-ammonia medium (pH 9.6). Electrophoretic separation was achieved with a voltage of 30 kV (positive CE mode), with an initial ramp of 7 s. The temperature of the capillary was kept constant at 25 C. The mass spectrometer was operated in the negative-ion mode. The optimized fragmenter voltage was 100 V for all analytes. For quantification, SIM mode was selected. The miz values corresponding to the [M-H] ions were 346 for AMP, 322 for CMP, 362 for GMP, 323 for UMP, and 347 for IMP. The results indicated that CE coupled to MS offered an alternative to other chromatographic methods for analysis of nucleotides and related compounds in infant formula samples. 

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