Problems of Forensic Sciences 2013 Vol. 96 (XCVI) 689-701
INVESTIGATING WITHIN-GROUP VARIATIONS OF BLACK BALLPOINT PEN INKS BASED ON DATA OBTAINEDBY MICRO-ATTENUATED TOTAL REFLECTANCE / FOURIER TRANSFORM INFRARED SPECTROSCOPY
Loong Chuen LEE1, Abdul Aziz JEMAIN 2
1Faculty of Health Science, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia
2School of Mathematical Sciences, Faculty of Science & Technology, Universiti Kebangsaan Malaysia, Bangi, Malaysia
Streszczenie
Currently, micro-ATR, one of the simplest nondestructive sampling techniques for FTIR spectroscopy, is continuously being investigated for its forensic applications to the examination of pen inks. This study aimed to explore the utility of micro-ATR/FTIR for distinguishing among models produced by a specific manufacturer (brand). A total of 14 black ballpoint pen varieties representing three separate brands were collected and analyzed. IR spectra were compared using the Pearson correlation coefficient after standardization. Then, a modified correlation coefficient was calculated to assist in evaluation of intra- and inter-variability present in inks. In general, the within-model variability was slightly higher than the within-brand variability. And pen models that differed only in terms of pen point sizes could contain a highly similar ink formulation. The within-brand variations varied depending on the manufacturer. In conclusion, micro-ATR FTIR spectroscopy is reproducible and can potentially be used to differentiate pens of the same make, but different models.
Słowa kluczowe
Forensic inks analysis; FTIR spectroscopy; Within-group variation; Differentiation index