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What is Which of the following methods is used for demonstrating old washed up blood-stains: and explain in detail?
B i.e. Luminol spray Luminol (3-aminophthalhydrazide) spray is most common blood reagent used for visualizing/demonstrating weak/ faint blood stains ie old washed up or cleaned up stains and blood stains in areas difficult to see such as outdoor vegetationsQ etc. - Screening tests for detection of blood stain as Benzidine, Phenopthalein Kastle - mayer, Ohotolidine, Leucomalachite green & Guaiacum tests are chemical tests depending upon presence of enzyme peroxidase in blood stain, which in presence of H202 (hydrogen peroxidase), oxidizes reagents to produce coloured compounds. Benzidine test is positive in hematuria, hemoglobinuria and myoglobinuriaQ Species of blood is identified by precipitin & gel diffusion testsQ; benzidine test can detect whether the stain is blood or not; so we are only left with acid dilution test for blood groupingQ