Level: Intermediate
Ashur Rael, Graduate Assistant, Indiana University–Purdue University Indianapolis
John V. Goodpaster, Associate Professor, Department of Chemistry and Chemical Biology; Associate Director, Forensic Sciences Program at IUPUI, Indiana University–Purdue University Indianapolis
Magnus Rydberg, Undergraduate Assistant, Indiana University–Purdue University Indianapolis
Courtney Cruse, Graduate Assistant, Indiana University–Purdue University Indianapolis
Zackery Roberson, Graduate Assistant, Indiana University–Purdue University Indianapolis
In the simplest of terms, a forensic chemist seeks to accomplish two tasks: 1) the identification of an unknown sample and 2) the comparison of an unknown sample to a known exemplar. Instrumental methods lie at the heart of the modern forensic examination of ignitable liquids, controlled substances, explosives and other forms of physical evidence.The search for instrumentation that offers the requisite sensitivity, selectivity and specificity for analytes does not end, even when established methods exist. Knowing the strengths and weaknesses of established methodologies is crucial for forensic chemists.To that end we apply JMP to both method development and spectral analysis.GC/VUV is a recent technique with great promise that we are currently exploring. Developing methods one factor at time is time-consuming and difficult to manage when multiple responses are important. Using JMP for design of experiments methods such as factorials and response surfaces allows simultaneous optimization of multiple experimental conditions while considering multiple responses. Understanding of the spectral data is difficult or impossible using visual or direct analysis. Using JMP for clustering and multivariate analysis readily elucidates the underlying spectral characteristics that drive differentiation and provides quantification of the method's ability to positively identify a compound.