Page 6 - The Smoking Gun Gunshot Residue

SAFETY PRECAUTIONS surface, as this solution could cause damage
1. The diphenylamine solution contains a high to any surface. The pipettes are to be used with
concentration of sulfuric acid. Students should the diphenylamine solution. Please dispose of
always wear gloves and be cautious when the pipettes in this kit after use. Additionally,
handling this chemical. Students should take goggles and lab coats are recommended when
care to not allow the solution to drip onto any handling the diphenylamine.

NOTES

❖ This kit includes a powder called called sodium rhodizonate. Before use in the gunshot residue
dection test, the powder in each bottle must be mixed with 5 mL of distilled water. Shake the
bottles to ensure that the powder and water mix into solution. This solution must be used within
3 days of mixing. Teachers may mix this solution the day before the lab or instruct students to
add the water immediately before performing the lab.

❖ During the detection test, emphasize that when students add the diphenylamine solution they
must observe the swab immediately for a blue reaction. The acid present in the solution will
cause the swab to turn black within a short period of time obscuring the original results. Again,
students should use extreme caution when handling the diphenylamine solution. It contains
sulfuric acid, which is highly corrosive. Gloves should be worn and appropriate surfaces used at
all times.

❖ The video clips for this lab may be accessed on the website at www.LyleAndLouise.com. Visit
the “Downloads” page, create/login to an account, and register your product to download the
supplemental material for this module.

6 THE MYSTERY OF LYLE AND LOUISE