An evaluation of the effect of incorporating metal salts into 1, 8 diazafluoren-9-one (DFO) formulations for fingermark enhancement. Issue 3 (May 2019) - Mayse, Kelly
Abstract: A study into the modification of 1, 8-diazafluoren-9-one (DFO) formulations by the additions of metal salts into the working solution is reported. Similar additions have been found to increase the fluorescence of marks developed using other amino acid reagents including 1, 2-indandione and the ninhydrin analogue 5-methylthioninhydrin. It was found that adding zinc chloride to give a 1:1 ratio of zinc ions:DFO molecules gave optimum fluorescence, and improvements in performance over the standard DFO formulation were achieved. Attempts to produce equivalent formulations with iron, nickel and palladium chlorides were unsuccessful. In a comparative trial with a 1, 2-indandione-zinc formulation on brown paper and cardboard substrates, 1, 2-indandione-zinc gave superior results and it was decided to focus further research on this reagent instead of DFO-zinc. Highlights: The effect of additions of different metal salts to DFO solutions is investigated. Enhanced fluorescence can be achieved by additions of zinc salts in a 1:1 M ratio with DFO. Comparisons with 1, 2 indandione – zinc shows that DFO-zinc formulations are less effective. 1, 2 indandione-zinc remains the most effective of the amino acid reagents tested to date.