In the criminal sphere, it is extremely important to identify perpetrators of crimes based on latent fingerprints (invisible to the naked eye) revealed at crime scenes and their corresponding objects. The present work aimed to evaluate four synthetic analogues of curcumin as possible IDL developers, and to compare their results with those of carbon black developer, as well as to reach the most adequate parameters in the use of the LTQ and FT-ICR mass spectrometers with the paper spray ionization (PS) source to study the chemical composition of the endogenous substances contained in the IDL. For this, a 24-1 factorial design was developed, where it was verified that the distance and voltage factors were the most influential for the increase in the response of signals, in the analysis of latent fingerprints by PS. Among the detected substances we can mention around 20 fatty acids, and squalene. Finally, four potential developers, synthetic analogues of curcumin, were compared with carbon black developer. The revelation of latent fingerprints occurred efficiently, allowing the visualization of minutiae, such as bifurcation and end of line, making it possible to classify them, according to the Vucetich Fingerprint Classification System.

Food additives are chemical substances added to improve organoleptic characteristics, in this context, there are several synthetic dyes, such as sunset yellow, tartrazine, erioglaucine, allura red, indigo carmine, and new coccine, that can also be identified through different analytical techniques such as infrared spectroscopy, UV-Vis spectrophotometry, high performance liquid chromatography with diode array detector and mass spectrometry. Therefore, the objective of this work was to compare methods developed for different analytical techniques, in order to identify the one that presents greater efficiency in certain applications. For this, the patterns of the dyes were analyzed, as well as their mixtures and foods that had them. As a result, the CLAE-DAD presents excellent selectivity and linearity of the calibration curves, but it presents higher LD and LQ values when compared to the UV-Vis, in turn the infrared provides information regarding functional groups and bonds. Mass spectrometry showed great capabilities in identifying the molecular formula and better selectivity in the absence of the erioglaucine dye. It is not feasible to indicate the best or worst analytical approach, but it is possible to point out which one is more suitable for each application. Regarding the quantification capacity, chromatography and UV-Vis are good alternatives, but in mixtures containing more than one dye, CLAE-DAD is more suitable due to the better selectivity. Regarding the identification capacity, mass spectrometry, especially FT-ICR MS, is the most appropriate technique to propose molecular formulas due to its high resolution and mass accuracy. The advantage of FTIR was the easier sample preparation, being able to analyze the dyes in the solid state.