Gun powder residues on forearms can be detected by?

ANSWER: (C) Dermal Nitrate TestREF: Parikh 6th edition page 4.39Dermal nitrate test or paraffin test was in use earlier to determint if a suspect has discharged firearm. The blow back powder residue deposits on the back of the palm and web spaces are collected on paraffin cast and tested for nitrates using diphenylamine reagent. This test is now obsolete as it gives false positive result with fertilizers, cigarettes and urine. Modern instrumental methods are used now.Tests to detect gunpowder residues:Paraffin/Dermal Nitrate test (now obsolete)Neutron Activation AnalysisAtomic absorption spectrophotometryScanning electron microscopy with X Ray analyser