A forensic study: Lead determination in gunshot residues

Electrochemical lead analyses of gunshot residues (GSRs) were performed using an acidic solution with a bare gold microelectrode in the presence of chloride ions. GSRs from four different guns (0.38 in. revolver, 12 caliber pump-action shotgun, 0.38 repeating rifle, and a 0.22 caliber semi-automatic rifle) and six different types of ammunition (CleanRange®, normal, semi-jacketed, especial 24g®, 3T®, CBC®, and Eley®) were analyzed. Results obtained with the proposed methodology were compared with those from an atomic absorption spectrometry analysis, and a paired Student's t-test indicated that there was no significant difference between them at the 95% confidence level. With this methodology, a detection limit of 1.7 nmol L− 1 (3σ/slope), a linear range between 10 and 100 nmol L− 1, and a relative standard deviation of 2.5% from 10 measurements were obtained.