The Colorimetric Identification of NO2− in Latent Fingerprints by Hydroxypropyl‐β‐cyclodextrin

Abstract

AbstractNitrate (NO2−) is a common explosion residue, whose identification is conducive to the detection of explosion cases. Herein, the chemical reaction of o‐phenylenediamine (OPD) with NO2− and the inclusion action of hydroxypropyl‐β‐cyclodextrin (HP‐β‐CD) are successfully used to visualize the latent fingerprint with attached NO2−. Furthermore, we have realized the semi‐quantitative analysis of NO2− in latent fingerprints by processing the color information of fingerprint images digitally according to the HSV color space, which is constructing the data relationship between the hue (H), saturation (S), value (V), and NO2− of the fingerprint image. This method is fast, non‐invasive, and convenient to operate. It realizes the simultaneous identification of the form of latent fingerprints. And its chemical composition(NO2−) provides a reference for the rapid detection of explosive residues of ammonium nitrate explosive in latent fingerprints.