[Study on amidation reaction between CdS/PAMAM and amino acid and its application to latent fingerprint development]

A new method for the development of latent fingerprints by CdS/PAMAM nanocomposites was explored in the present research. Amidation reaction between terminal carboxylate groups of amino acids and terminal amino groups of PAMAM G4. 5 dendrimers was studied by FTIR spectrometry. The reacting processes under different conditions were monitored by H(1267/1735) (the relative ratio of peak height) in order to find out the optimized condition and developing method. The results indicated that the reacting processes were affected remarkably by the changes in temperature. The reaction was efficient under 90 degrees C within 4 hours, while the reacting speed decreased after 3 hours under 120 degrees C. CdS/PAMAM was utilized as the latent fingerprint developing reagent and compared with the routine one. The results indicated that the fluorescence intensity of the former is 65 times higher than that of the latter. Great predominance in florescence could be observed when CdS/PAMAM and the routine developing reagent were compared. Latent fingerprints on the surface of different objects were developed under 120 degrees C within 0.5-3 h. Good developing results could be obtained under the optimized condition. The method is simple, rapid, highly sensitive, safe and economical.