ISSN: 0022-1198
CODEN: JFSCA
Page Count: 6

Evaluation of Principal Components Analysis with High-Performance Liquid Chromatography and Photodiode Array Detection for the Forensic Differentiation of Ballpoint Pen Inks
Kher, AA
Materials and Forensic Science, University of Technology, NSW

Green, EV
Materials and Forensic Science, University of Technology, NSW

Mulholland, MI
Materials and Forensic Science, University of Technology, NSW

(Received 20 March 2000; accepted 29 August 2000)

Abstract

Inks from seven black and eight blue ballpoint pens were separated by a high-performance liquid chromatography (HPLC) method utilizing a photodiode array detection (PDA). A classifier flowchart was designed for the chromatographic data based on the presence or absence of certain peaks at different wavelengths to qualitatively discriminate between the inks. The same data were quantitatively classified by principal components analysis (PCA) to estimate the separation between a pair of classes of ink samples. It was found that the black ballpoint pen inks were discriminated satisfactorily utilizing two-dimensional data of the peak areas and retention times at the optimum wavelengths. The blue pens were discriminated by analyzing the chromatographic data at four different wavelengths simultaneously with a cross-validated PCA. The results of this study indicated that HPLC-PDA coupled with chemometrics could make a powerful discriminating tool for the forensic chemist, especially when analyzing extensive and/or complex data.

Keywords:
forensic science, chemometrics, principal components analysis, ballpoint pen inks, classification, high-performance liquid chromatography

Paper ID: JFS15061J
DOI: 10.1520/JFS15061J
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