This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Death and Investigations, Subject name: Forensic Medicine
Gunshot residue on hands can he detected by which test- 
Select and explain. 
A. Benzidine test, B. Phenolphthalein test, C. Dermal nitrate test, D. Hydrogen activation analysis
C: Dermal nitrate test
Answer: C: Dermal nitrate test 
Explanation: Ans. is 'c' i.e., Dermal nitrate test o Dermal nitrate/ paraffin/diphenylamine test:It is used to detect firearm residues on the hands of the suspectIn this, the hands are coated with a layer of liquid paraffin. After cooling, the casts are removed & treated with an acid solution of diphenvlamine, a reagent used to detect nitrates & nitrites that originate from gunpowder & is deposited on the skin of the person who has fired the shot.A positive test is indicated by the presence of blue flakes in the paraffin.o Benzidine test- most sensitive test for detection of blood,o Phenolphthalein / Kastle Mayer test-screening test for blood stainso Harrison & Gilroy test hydrogen activation analysis- is used to detect heavy metal. These heavy metals are detected from entrance wound where they are components of the residue discharged from the cartridge of a firearm weapon.