Paint chips transferred in a fatal hit-and-run are examined in the laboratory. Colour and layer sequence have been documented by stereomicroscopy. Which instrumental method is specifically used to identify the resin or binder component of each paint layer?

• A Pyrolysis gas chromatography ✓
• B Atomic absorption spectrophotometry
• C X-ray diffraction crystallography
• D Polarised light microscopy

Explanation

Automotive paint consists of pigment particles dispersed in an organic binder. Pyrolysis gas chromatography heats microgram quantities of the paint, volatilising the organic binder whose fragmentation pattern identifies the resin system and helps discriminate paints of similar colour. Atomic absorption and X-ray diffraction address metallic elements and crystalline pigments respectively, while polarised light microscopy is a screening tool for pigment and layer features, not the binder.

Reference: Parikh's Textbook of Medical Jurisprudence, Forensic Medicine and Toxicology, 7th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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