Surface plasmon spectroscopy of serum albumin protected prism‐shaped silver nanoparticles is used as simple and effective sensing tool to detect glutamate salts. The approach does not require any electrochemical setup to detect glutamates, in contrast to common techniques to detect glutamates in general. Experiments reveal that upon presence of high concentrations of glutamate salts, the prism‐shaped nanoparticles are transformed to smaller‐sized nanoclusters, while the remaining nanoparticles are assembled to form aggregates. Control experiments confirm that the interaction is specific to the serum albumin coating, the prism shape of the nanoparticles, and to silver.