Development of In-House Standards and the Forensic Analysis of Polymers Using Laser Ablation Inductively Coupled Plasma Mass Spectrometry

This research study sought to develop a method for creating in-house polymer standards with varying elemental composition. A micro-compounder was designed and fabricated that would mix different polymers and additives in order to create a homogeneous standard with any desired elemental composition. These standards could then be used for analyzing polymers with a laser ablation inductively coupled mass spectrometer (LA-ICP-MS). Unfortunately the micro-compounder failed to produce a homogeneous sample due to design issues. Regardless of the micro-compounder, certified polyethylene standards ERM-EC680K and 681K were purchased and used to test the potential of LA-ICP-MS in analyzing polymers. This included studies in homogeneity, quantitative analysis, and comparison of five unknown polymer samples from automobile headlamps. Only semi-quantitative or qualitative analysis could be performed due to the lack of a known internal standard. Comparison of elemental ratios of the same polymer over a number of analyses showed no differentiation, while comparison of the five polymers' elemental profiles proved useful in discriminating each polymer from the others. It's apparent that LA-ICP-MS can potentially be utilized for the forensic analysis of polymers.