Evaluation of Lumicyano cyanoacrylate fuming process for the development of latent fingermarks on plastic carrier bags by means of a pseudo operational comparative trial

There are a number of studies discussing recent developments of a one-step fluorescent cyanoacrylate process. This study is a pseudo operational trial to compare an example of a one-step fluorescent cyanoacrylate product, Lumicyano™, with the two recommended techniques for plastic carrier bags; cyanoacrylate fuming followed by basic yellow 40 (BY40) dyeing and powder suspensions. 100 plastic carrier bags were collected from the place of work and the items were treated as found without any additional fingermark deposition. The bags were split into three and after treatment with the three techniques a comparable number of fingermarks were detected by each technique (average of 300 fingermarks). The items treated with Lumicyano™ were sequentially processed with BY40 and an additional 43 new fingermarks were detected. Lumicyano™ appears to be a suitable technique for the development of fingermarks on plastic carrier bags and it can help save lab space and time as it does not require dyeing or drying procedures. Furthermore, contrary to other one-step cyanoacrylate products, existing cyanoacrylate cabinets do not require any modification for the treatment of articles with Lumicyano™. To date, there is little peer reviewed articles in the literature on trials related to Lumicyano™ and this study aims to contribute to fill this gap

Pseudo-operational trials of Lumicyano solution and Lumicyano powder for the detection of latent fingermarks on various substrates

This study presents pseudo-operational trials comparing a one-step fluorescent cyanoacrylate process with a number of other enhancement techniques on a variety of substrates. This one-step process involves a product, 4% Lumicyano, which is a solution consisting of 4% by weight of a powdered dye (Lumicyano powder) dissolved in a cyanoacrylate-based solution (Lumicyano solution). The cyanoacrylate in the Lumicyano solution may be of a higher quality than that used in the two-step products.One hundred items were collected from the place of work for each trial. Trial 1 involved a comparison of 4% Lumicyano with the conventional two-step cyanoacrylate fuming-dye staining for the detection of latent fingermarks on plastic carrier bags. Trial 2 assessed the quality of the Lumicyano solution (with no powdered dye) but used in a two-step process with basic yellow 40 (BY40). Trial 1, using 4% Lumicyano powder and traditional cyanoacrylate → BY40 detected a similar amount of fingermarks (~295); however, sequential BY40 treatment (i.e., after 4% Lumicyano) detected an additional 30% marks. Trial 2 resulted in the detection of 565 marks after Lumicyano solution → BY40 in comparison to 489 marks after traditional cyanoacrylate fuming and BY40 staining. Trials 3 through 5 compared 4% Lumicyano, 1,2-indanedione-zinc, and ninhydrin on junk mail, magazines, and cardboard used for food or cosmetic packaging; the detection rate was low for all techniques and substrates. Trial 6 on cardboard packaging using 4% Lumicyano, black iron-oxide powder suspension, and magnetic powder also provided a low detection rate. Trial 7, using 4% Lumicyano → BY40, solvent black 3, and iron-oxide powder suspensions on cardboard packaging from a fast food chain, indicated that 4% Lumicyano → BY40 might be a suitable alternative to solvent black 3 and iron-oxide powder suspensions for suspected greasy marks

Bromidotetra­kis­(2-isopropyl-1H-imidazole-κN 3)copper(II) bromide

The CuII atom in the title salt, [CuBr(C6H10N2)4]Br, is coordinated in a square-pyramidal geometry by four imidazole N atoms and one bromide anion that is located at the apex of the pyramid. The cations and the anions form a two-dimensional network parallel to (001) through N—H⋯Br hydrogen bonds

The optimisation of fingermark enhancement by VMD and Lumicyano™ on thermal paper

The enhancement of fingermarks on thermal paper can be challenging due to background staining caused by polar solvents used in fingermark enhancement techniques such as ninhydrin. This study explored a commercial one-step superglue fuming process, Lumicyano™, and Vacuum Metal Deposition (VMD) to develop fingermarks on this substrate and overcome this issue. Different sequential treatments involving Lumicyano™ and a combination of VMD methods were investigated with varying degrees of success with some sequences being highly sensitive. The VMD processes, however, were observed to generally be more effective at enhancing marks, whereas Lumicyano™ provided little or no benefit on this paper type. The results indicate that Lumicyano™ is only beneficial as a pre-treatment when the entire sequence of gold/zinc and silver/zinc is taken to completion. The gold/zinc and silver/zinc VMD processes were optimised on five different thermal papers, and the optimised techniques were then directly compared to determine which was more successful on each thermal paper type as a single treatment

Bromidotetra­kis­(1H-2-ethyl-5-methyl­imidazole-κN 3)copper(II) bromide

The CuII ion in the title compound, [CuBr(C6H10N2)4]Br, is coordinated in a square-based-pyramidal geometry by the N atoms of four imidazole ligands and a bromide anion in the apical site. Both the CuII and Br− atoms lie on a crystallographic fourfold axis. In the crystal, the [CuBr(C6H10N2)4]+ complex cations are linked to the uncoordinated Br− anions (site symmetry ) by N—H⋯Br hydrogen bonds, generating a three-dimensional network. The ethyl group of the imidazole ligand was modelled as disordered over two orientations with occupancies of 0.620 (8) and 0.380 (8)

An alternative carrier solvent for fingermark enhancement reagents

Solstice® Performance Fluid (PF), trans-1-chloro-3,3,3-trifluoropropene, is presented as an alternative to HFE7100, methoxy-nonafluorobutane, as a carrier solvent in a number of chemical formulations used for the visualisation of latent fingermarks. The supply of HFE7100 may be at riskdue to a recent European Union regulation to control global warming. Laboratory trials using split depletions and a pseudo-operational trial of 1000 porous samples have shown that Solstice® PF is a viable alternative to HFE7100 for the chemical formulations of ninhydrin and 1,2-indanedione. Other preliminary trials have also indicated that Solstice® PF can be used as a carrier solvent for the zinc toning of marks found using ninhydrin as well as the α-naphtholflavone fixative solution for iodine developed marks. Results from the pseudo-operational trial demonstrate that the number of marks detected by ninhydrin and 1,2-indanedione formulations for each carrier solvent is comparable. When compared to HFE7100, advantages of Solstice® PF include a very low global warming potential and atmospheric lifetime in addition to a higher wetting index and lower costs. This study also provides a validation study that supports the potential replacement of DFO with 1,2-indanedione

An assessment of a portable cyanoacrylate fuming system (LumiFume™) for the development of latent fingermarks

The effectiveness and suitability of a portable cyanoacrylate fuming system (LumiFume™) with Lumicyano™ at detecting latent fingermarks was assessed. The first phase of the study compared the LumiFume™ system with traditional cabinet fuming and black/white powder suspension for the development of latent fingermarks on a variety of surfaces (glass, plastic bin bag, laminated wood and tile) by means of depletion series’ from 10 donors and four ageing periods (1, 7, 14 and 28 days). The portable fuming system provided superior quality of developed marks on glass and laminated wood whereas powder suspension was better on bin bags and all three techniques were comparable on tile. A decrease in mark quality was recorded from 1-14 days for the fuming techniques before an increase at 28 days. Lumicyano™ fluorescence stability studies over a 28 day period by means of depletion series’ on glass slides and plastic bin bags revealed better quality marks for the portable system LumiFume™; however, storing marks under light conditions expedited deterioration for both systems. All marks developed with Lumicyano™ were subsequently treated with BY40 resulting in further improvement in mark quality for all substrates and ageing periods, with the exception of laminated wood which absorbed the fluorescent stain reducing the contrast in the process. The second phase of the study consisted of a pseudo-operational trial on 300 various substrates (e.g. glass bottles, aluminium cans, plastic bags) recovered from recycling bins. LumiFume™ and Lumicyano™ yielded 1,469 marks whereas Lumicyano™ cabinet fuming and powder suspension yielded 1,026 and 641 marks respectively. Similar to the first phase of the study, further treatment of the Lumicyano™ treated marks with BY40 resulted in further quality improvement as well as additional new marks. The LumiFume™ system produced results at least equivalent to the traditional cabinet fuming with Lumicyano™ highlighting its potential for implementation into casework to process crime scenes

A comparison between atmospheric/humidity and vacuum cyanoacrylate fuming of latent fingermarks

A number of pseudo-operational trials were set up to compare the atmospheric/humidity and vacuum cyanoacrylate fuming processes on plastic carrier bags. The fuming processes were compared using two-step cyanoacrylate fuming with basic yellow 40 (BY40) staining and a one-step fluorescent cyanoacrylate fuming, Lumicyano 4%. Preliminary work using planted fingermarks and split depletions were performed to identify the optimum vacuum fuming conditions. The first pseudo-operational trial compared the different fuming conditions (atmospheric/humidity vs. vacuum) for the two-step process where an additional 50% more marks were detected with the atmospheric/humidity process. None of the marks by the vacuum process could be observed visually; however, a significant number of marks were detected by fluorescence after BY40 staining. The second trial repeated the same work in trial 1 using the one-step cyanoacrylate process, Lumicyano at a concentration of 4%. Trial 2 provided comparable results to trial 1 and all the items were then re-treated with Lumicyano 4% at atmospheric/humidity conditions before dyeing with BY40 to provide the sequences of process A (Lumicyano 4% atmospheric - Lumicyano 4% atmospheric - BY40) and process B (Lumicyano 4% vacuum - Lumicyano 4% atmospheric - BY40). The number of marks (visual and fluorescent) was counted after each treatment with a substantial increase in the number of detected marks in the second and third treatments of the process. The increased detection rate after the double Lumicyano process was unexpected and may have important implications. Trial 3 was performed to investigate whether the amount of cyanoacrylate and/or fuming time had an impact on the results observed in trial 2 whereas trial 4 assessed if the double process using conventional cyanoacrylate, rather than Lumicyano 4%, provided an increased detection rate. Trials 3 and 4 confirmed that doubling the amount of Lumicyano 4% cyanoacrylate and fuming time produced a lower detection rate than the double process with Lumicyano 4%. Furthermore, the double process with conventional cyanoacrylate did not provide any benefit. Scanning electron microscopy was also performed to investigate the morphology of the cyanoacrylate polymer under different conditions. The atmospheric/humidity process appears to be superior to the vacuum process for both the two-step and one-step cyanoacrylate fuming, although the two-step process performed better in comparison to the one-step process under vacuum conditions. Nonetheless, the use of vacuum cyanoacrylate fuming may have certain operational advantages and its use does not adversely affect subsequent cyanoacrylate fuming with atmospheric/humidity conditions

1-Dimethyl­amino-9,10-anthraquinone

In the crystal structure of the title compound, C16H13NO2, adjacent mol­ecules are linked through C—H⋯π and π–π [centroid–centroid distances = 3.844 (2) Å] contacts. The anthracene ring system and dimethyl­amino group are oriented at a dihedral angle of 38.4 (1)°. In the crystal, the mean planes of adjacent anthracene units are inclined at angles of 59.3 (1), 75.7 (1) and 76.0 (1)°

2,9-Di-3-pentyl­anthra[1,9-def:6,5,10-d′e′f′]diisoquinoline-1,3,8,10-tetrone

The asymmetric unit of the title compound, C34H30N2O4, contains four independent half-mol­ecules, the complete mol­ecules being generated by inversion symmetry. The mol­ecules each have planar (within 4σ) perylene­tetra­carb­oxy­lic diimide fragments with bent side chains. In one of the independent mol­ecules, each 3-pentyl fragment is disordered over two conformations in a 7:3 ratio. In the crystal, π–π inter­actions link mol­ecules into stacks propagated in [010]. The crystal packing also exhibits weak inter­molecular C—H⋯O hydrogen bonds