The morphology and particle size distribution of reaction precipitation systems is very sensitive to mixing. This is due to very fast reaction rate, making nucleation and growth to be controlled by micro and meso mixing. In this work a stopped flow system is used to study the reaction rate, induction time and growth rate for the formation of Ag2S nanoparticles. The stopped flow reactor has the capability of mixing in milliseconds thus separating the kinetic phenomena from the mixing phenomena. The kinetic of particle formation is studied using fluorescence technique. The solution is irradiated at 230 wavelengths and the fluorescence spectrum followed as function of time. The reaction rates are determined using conductivity measurements, which is correlated to the concentration of the ionic species in solution. Both measurements are combined to estimate induction time. Possible applications of Ag2S particles are in sensing, including chemical and warfare agent detection as well as environmental monitoring.