Application of PAMAM dendrimers for detecting latent fingerprints on adhesive tapes

Photoluminescent PAMAM dendrimer was studied as a fluorescent marker for developing latent fingerprint deposited on adhesive tapes in the conditions of different pH values and excitation wavelengths. The results show: When the pH value of PAMAM dendrimers solution was more than 7, the impactful composition of fingerprints can be eroded and the detecting effect decreases; treated fingerprints emitted strong visible blue fluorescence with clear lines and characters and the detecting effect was good when the pH value was within the range of 4-7.The blue fluorescent emission of PAMAM was easily disturbed by the blue visible light emitted from impurities in adhesive tapes in the irradiation of 365 nm UV light, thus the contrast between fingerprint residue and background was only 28.8%; it could be enhanced to about 90% by changing the UV exciting light into visible narrow-band light or nature white light because of the elimination of effect of impurities in adhesive tapes, which could also reduce the harm of UV light to people. PAMAM was an environmental-friendly, effective reagent for latent fingerprints on sticky side of adhesive tapes.