The article presents the results of studies on the method of sensibilizing dactyloscopic traces directly from the gaseous phase. The detection of dactyloscopic traces on absorbtive surfaces requires specific revealing methods, whose essential aspect is the need to deliver reagent to the place of occurrence of the corresponding component of trace forming substance. In practice, for many years, various types of solutions have been used for this purpose, such as DFO, ninhydrin and 1,2-indanedione. Within the framework of this study, research was carried out on revealing fingerprints on absorptive surfaces with the use of genipin, under reduced pressure conditions and in order to compare against the liquid phase. Based on the results of the tests carried out and results obtained, it should be stated that the genipin vacuum sublimation technique can be successfully used to reveal fingerprints on absorptive surfaces. The traces revealed are visible both under white light and fluorescence illumination. The effectiveness of the dactyloscopic trace sensibilization method in the gaseous phase has been demonstrated with regard to such substances as ninhydrin and genipin.

This article provides the results of research on the uniformity of amino acid test strips used with fluorescent DFO method. Ready to use amino acid test strips made of the absorptive material containing four reactive fields of exponentially decreasing amino acid concentrations, designed for DFO, ninhydrin, 1,2-indanedione methods were used in the study. The test strips were treated with DFO solution in order to measure the fluorescence emission level of DFO-amino acid reaction product for respective reaction fields. Based on the obtained results, the repeatability of emitted fluorescence measurements was observed, thus confirming the usability of test strips in DFO method verification of newly prepared reagents as well as the use of this method in routine laboratory work. Based on the findings, it should be assumed that test strips are also effective and suitable for verification of correctness of preparation of working solutions for the remaining amino acid based fingerprint visualization methods such as: ninhydrin, 1,2-indanedione, and 1,2-indanedione with zinc chloride.

The study shows the results of fluorescence emission intensity measurements of the reaction products of selected amino acids with DFO, 1,2-IND and 1,2-IND - zinc chloride on absorptive surfaces. Conducted research addressed the following variables: type of developing reagent, type of surface, type of amino acid and sample storage time. It was confirmed that the above factors affected the fluorescence intensity of developed fingerprints. Furthermore, the studies proved that fluorescence intensity of reaction products between amino acids and 1,2- IND stored for 1 or 7 days increased for the majority of samples upon addition of zinc chloride to the developing reagent. For samples stored for 4 months the highest fluorescence emission intensity was observed for DFO. No significant differences were found in fluorescence spectral characteristics of tested compounds, depending on the type of surface.