Evaluation of reagents for the chemical enhancement of fingermarks on porous surfaces : optimisation and characterisation of the 1,2-indanedione technique

University of Technology, Sydney. Faculty of Science.There is a continual search for new and improved reagents to detect fingermarks on a variety of surfaces. With increased technology and resources the possibilities are continually expanding. 1,2-Indanedione is a relatively new reagent for the development of fingermarks on porous surfaces. Its boundaries have not been completely explored nor has the method of reaction with fingermarks been determined. The initial aim of this project was to investigate the fingermark reagent 1,2-indanedione and determine if it was a viable reagent for routine use in Australia. The secondary aim was to study the reaction that occurs between 1,2-indanedione and amino acids and the subsequent reaction with metal salts to gain further insight into the reaction than has been previously published. Additionally the fingermark reagent 5-methylthioninhydrin, which although had shown good results in detecting fingermarks in the early 1990’s, did not seem to be widely used or studied since its commercial manufacture began. A new reagent for the problematic and increasingly encountered thermal paper, ThermaNin, was also evaluated and compared to other proposed methods for the development of fin germ arks on thermal paper. The investigation of 1,2-indanedione as a fingermark reagent for use in Australia was performed by comparing a number of formulations and development procedures, encompassing all published recommendations as well as some novel approaches. 1,2-indanedione formulations were compared with respect to initial colour, fluorescence, concentration of the reagent, acetic acid concentration and the effect of different carrier solvents. Numerous development conditions were also investigated, including a conventional oven, a heat press and humidity. Further enhancement using metal salts and liquid nitrogen was also evaluated. The heat press set at 165°C for 10 s proved to give the best initial colour and most intense luminescence. Secondary metal salt treatment improved initial colour and luminescence and was found to provide consistent results despite different environmental conditions. It is for this reason that it is recommended that metal salt treatment consistently be performed after treatment with 1,2-indanedione or included in the formulation of 1,2-indanedione. The Polilight, the VSC 2000, and the Condor Chemical Imaging macroscope have been used to detect fingermarks developed with 1,2-indanedione on a variety of high- and low- quality porous and semi-porous surfaces with impressive results overall. Laboratory and field tests were conducted to compare 1,2-indanedione with DFO and ninhydrin as well as to investigate the position of 1,2-indanedione in the sequence of reagents for fingermark detection on porous surfaces. Overall 1,2-indanedione proved to be a viable alternative to tradition methods for the detection of fingermarks on porous surfaces, with more fingermarks being developed using this reagent on real samples than both DFO and ninhydrin and a combination of the two reagents. The isolation of a single pure product from the reaction of 1,2-indanedione with several different amino acids was not achieved. The study was able to establish that 1,2-indanedione reacts differently with different amino acids with some reactions, such as those with alanine and cysteine, following a similar pathway. A study performed by nuclear magnetic resonance spectroscopy and colour reactions showed that increasing the content of water in the reaction retarded the kinetics of the reaction and thus it is possible that the concentration of water in the reaction may influence the path the reaction takes. Solid state nuclear magnetic resonance spectroscopy indicated that the product of the reaction is ionic, which may help explain the problems encountered on separation and isolation of the product. Thermal and elemental analysis provided some information on the by-products released by the reaction, whilst mass spectroscopy provided information on the possible pathway of the reaction. The results of this study support the proposal made by Petrovskaia (1999) that the main reaction product of 1,2-indanedione and amino acids is a Ruhemann’s purple type product with a molecular mass of 275. A study of the reaction between metal salts and the 1,2-indanedione/amino acid product was also performed on a crude reaction mixture. This was due to the inability to provide a pure starting materials as well as the unsuccessful separation of the complex by thin layer chromatography. The information gained; however, from a study via nuclear magnetic resonance spectroscopy, mass spectroscopy, UV-visible spectroscopy and infrared spectroscopy indicates that two 1,2-indanedione molecules react with the nitrogen atom in the amino acid forming a tridentate ligand which then complexes with the metal ion. The evaluation of 5-methylthioninhydrin found that the reagent is superior to ninhydrin; however, 1,2-indanedione exhibits much stronger luminescence when used to treat latent fingermarks. The high cost of the reagent accompanied by the fact that 1,2-indanedione was found to be a superior reagent and is already in use in many laboratories precludes a recommendation for its routine use. ThermaNin was evaluated against other recommended reagents for the development of fingermarks on thermal paper. ThermaNin itself was found to be extremely sensitive to water and humidity and must be made fresh before its use due to poor stability. Once again a 1,2-indanedione formulation, albeit without acetic acid, was found to be the optimal method to detect fingermarks on this particular surface

Use of dichloromethane in fingerprint reagent formulations

Letter to the edito

Evaluation of 5-Methylthioninhydrin for the Detection of Fingermarks on Porous Surfaces and Comparison

The chemical 5-methylthioninhydrin was developed in the early 1990s for treating fingermarks on porous surfaces. Although many researchers showed the promise of this chemical during the years between 1990 and 1997, current research indicates that this reagent is sill not commonly used in casework. The current study assessed the commercially produced 5-methylthioninhydrin and compared it to the more commonly used reagents for detecting fingermarks on porous surfaces. The study found that 5-methylthioninhydrin is superior to ninhydrin; however, 1,2-indanedione produced a much stronger luminescence when used to treat latent fingermarks. Comparable fluorescence was produced with 5-methlthioninhydrin after metal salt treatment to DFO; the high background detracts from the ridge detail, however. The study concludes that although the cost of 5-methylthioninhydrin is higher than for conventional reagents, its use may be justified in some circumstances. The second article begins with an illustrated step-by-step demonstration of the technique for blending two exposures of the same scene. It involves the use of layers within Adobe Photoshop CS and then placing one exposure overtop of another exposure. The best qualities of each exposure are then used in the final print. The article then examines a few applied forensic applications of the blending of two exposures, including a technique for rescuing underexposed images. This issues section on Society Business (Canadian Identification Society) addresses Society awards, the Presidents message," the 29th CIS Educational Conference, guidelines for authors, a listing of award winners and past presidents, and a listing of staff member

Regional specialization within the intestinal immune system.

The intestine represents the largest compartment of the immune system. It is continually exposed to antigens and immunomodulatory agents from the diet and the commensal microbiota, and it is the port of entry for many clinically important pathogens. Intestinal immune processes are also increasingly implicated in controlling disease development elsewhere in the body. In this Review, we detail the anatomical and physiological distinctions that are observed in the small and large intestines, and we suggest how these may account for the diversity in the immune apparatus that is seen throughout the intestine. We describe how the distribution of innate, adaptive and innate-like immune cells varies in different segments of the intestine and discuss the environmental factors that may influence this. Finally, we consider the implications of regional immune specialization for inflammatory disease in the intestine

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These guidelines are a consensus work of a considerable number of members of the immunology and flow cytometry community. They provide the theory and key practical aspects of flow cytometry enabling immunologists to avoid the common errors that often undermine immunological data. Notably, there are comprehensive sections of all major immune cell types with helpful Tables detailing phenotypes in murine and human cells. The latest flow cytometry techniques and applications are also described, featuring examples of the data that can be generated and, importantly, how the data can be analysed. Furthermore, there are sections detailing tips, tricks and pitfalls to avoid, all written and peer-reviewed by leading experts in the field, making this an essential research companion