A method for the reproducible preparation of a silver colloid with strong surface-enhanced Raman scattering (SERS) properties, good stability with a zeta potential of À55 mV and a shelf life exceeding 1 year is reported. The mean particle size is 20 nm with a narrow size distribution of 10-30 nm. The colloid is produced by the reduction of silver nitrate with hydroxylamine phosphate to give a negatively charged phosphate surface on the silver particles. This is an ultrafast room temperature reaction and with controlled rapid addition and dispersion of reagents, very reproducible batches of colloid can be prepared making it suitable for commercial applications of Surface enhanced resonance Raman scattering(SER(R)S) spectroscopy. The stability of the colloid is attributed to the extremely low solubility product (K sp ) of silver phosphate. Characterisation and stability study data for this colloid have been obtained by ultraviolet-visible spectroscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy, particle size analysis and SERS analyses using a 514 nm laser on a Raman spectrometer. A SERS method to detect and to identify riboflavin in a vitamin B complex tablet is reported to illustrate a SERS application based upon the use of this silver colloid.

A kinetic study of the rhodium complex catalyzed carbonylation of methanol is reported. The reaction was investigated at CO pressures between 1 and 50 atm and in the temperature range 150-225OC. It was discerned to be zero order with respect to the reactants, and first order with respect to the catalyst and promotor. The activation energy was found to be 14.7 kcal/mol, the values for the activation entropy and enthalpy being in good agreement with the assumption that the oxidative addition is the ratedetermining step in the catalytic cycle.

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