Patent ID: 8637319

Claim:
A method of detecting human or animal blood on a surface, comprising the step of applying to the surface to be investigated a liquid luminol composition comprising a luminol compound, hydrogen peroxide or other peroxidic oxidising agent and an alkaline agent in an amount providing a pH within the range of 10 to 14, characterised in that, prior to said liquid composition, a suspension of inorganic powder selected from the group consisting of silicas, aluminas, titanias, alkaline metal oxides, alkaline earth metal oxides, zinc oxides, zirconias, water insoluble phosphates, micro- and nano-particles of oxide or non oxide semiconductors, functionalised derivatives thereof and mixtures containing varying proportions thereof is applied onto the surface to be investigated, wherein the inorganic powder or the functionalised derivative or the mixture are suspended in an aqueous solvent or in an organic solvent; and wherein the blood comprises haemoglobin which contains iron ions.