Trace level detection of putrescine and cadaverine in food samples using a novel rhodanine-imidazole dyad and evaluation of its biological properties.

Biogenic amines are important indicators of food spoilage and quality. Food safety is significantly influenced by biogenic amines such as Putrescine and Cadaverine, produced by microbes during food spoilage. Herein, a colorimetric probe for detecting Putrescine and Cadaverine based on a chemo-dosimeter strategy has been proposed. The probe L irreversibly binds with Putrescine and Cadaverine through an aza-Michael addition reaction in which the dicyanomethyl group of the probe is substituted by the primary amine group from the biogenic amines. This chemical reaction rapidly changes color from colorless to pale green. The probe could detect Putrescine and Cadaverine in trace levels of 52 nM and 18 nM, without much interference from other common biogenic amines. The binding mechanism of probe L with biogenic amines was confirmed using H NMR, IR, and DFT studies. The detection procedure is made portable and affordable by using a smartphone camera to capture colorimetric changes and convert them into RGB coordinates. Test paper strips coated with the probe were developed to illustrate its real-world analytical application. The potential application of probe L in real samples was demonstrated using in-vivo models of Prawn and Beef using test paper strips. Probe L showed satisfactory performance for detecting Putrescine and Cadaverine in the vapor phase.