Forensic Discrimination of Steel Wire by Determination of Trace Elements with ICP-AES

The application of inductively coupled plasma atomic emission spectrometry (ICP-AES) to the determination of trace elements in steel wires was investigated for the forensic discrimination of wires produced by different manufacturers based on comparing the elemental composition. About 50 mg of a wire sample was accurately weighed and dissolved into a mixture of 1 mL of HCl and 1 mL of HNO3 by heating at 80°C for 30 minutes, followed by dilution to 10 mL after the addition of a Y solution as an internal standard. Five elements (P, Cr, Mn, Ni and Cu) in the solution of samples prepared as described above were determined using standard solutions for calibration containing the same concentration of Y and reagents as the sample solution. The analytical results of the five elements in NIST Standard Reference Material 16f (Steel Basic Open-Hearth) showed satisfactorily good agreement with the certified values, having relative standard deviations from 0.6% for Ni to 1.2% for P. All of 21 pairs among 7 kinds of wire samples could be discriminated by comparing the concentrations of five elements obtained by the present method.