Method

Prior to fingerprint deposition the brass samples were first ultrasonically cleaned in micro 90 solution for 15 minutes.

Following this the samples were then cleaned ultrasonically in acetone for 5 minutes, rinsed in distilled water,  then sonicated in iso-proponal, rinsed again, sonicated in ethanol, and rinsed for a last time, before being dried in nitrogen.

Finger prints were deposited by pressing onto the metal surface for 1-2 seconds. The samples were then left in air at room temperature for a set amount number of hours to corrode.

After the designated hours were up, the particular sample was washed using the method previously used by bond et al. in 0.5 L of warm water containing 3-4 drops of commercial detergent.

The samples were then placed in an XPS machine.

Results