Malaysian
Journal of Analytical Sciences Vol 18 No 2 (2014): 226 – 233
FORENSIC ANALYSIS OF BLUE BALLPOINT PEN INKS ON
QUESTIONED DOCUMENTS BY HIGH PERFORMANCE THIN LAYER
CHROMATOGRAPHY TECHNIQUE (HPTLC)
(Analisis Forensik Dakwat Biru Pen
Mata Bulat Atas Dokumen Yang Dipertikai Dengan Kromatografi Lapisan Nipis
Berprestasi Tinggi (HPTLC))
Loong Chuen Lee*, Sitti Mariam
Nunurung, Ab Aziz Ishak
Forensic Science
Programme, Faculty of Health Sciences,
Universiti
Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, 50300 Kuala Lumpur, Malaysia
*Corresponding author: lc_lee@ukm.edu.my
Abstract
Nowadays,
crimes related to forged documents are increasing. Any erasure, addition or
modification in the document content always involves the use of writing
instrument such as ballpoint pens. Hence, there is an evident need to develop a
fast and accurate ink analysis protocol to solve this problem. This study is
aimed to determine the discrimination power of high performance thin layer
chromatography (HPTLC) technique for analyzing a set of blue ballpoint pen
inks. Ink samples deposited on paper were extracted using methanol and
separated via a solvent mixture of ethyl acetate, methanol and distilled water
(70: 35: 30, v/v/v). In this method, the discrimination power of 89.40% was
achieved, which confirm that the proposed method was able to differentiate a
significant number of pen-pair samples. In addition, composition of blue pen
inks was found to be homogeneous (RSD <2.5%) and the proposed method showed
good repeatability and reproducibility (RSD <3.0%). As a conclusion, HPTLC
is an effective tool to separate blue ballpoint pen inks.
Keywords: forensic science,
ink analysis, High
Performance Thin Layer Chromatography,
discrimination power, ballpoint pen
Abstrak
Baru-baru
ini, jenayah yang berkaitan dengan dokumen palsu semakin meningkat. Sebarang
pemadaman, penambahan atau pengubahsuaian dalam kandungan dokumen sering
melibatkan penggunaan alatan tulis seperti pen mata bulat. Oleh itu, ia terdapat satu keperluan yang nyata untuk
membangunkan satu protokol analisis dakwat yang cepat dan tepat untuk
menyelesaikan masalah ini. Kajian ini bertujuan
untuk menentukan kuasa diskriminasi teknik lapisan nipis berprestasi tinggi
(HPTLC) menganalisis satu set dakwat biru pen mata bulat. Sampel dakwat yang
termendap pada kertas diekstrak mengguna metanol dan dipisahkan dengan campuran
pelarut yang mengandungi etil asetat, etanol dan air suling (70:35:30). Dalam
kaedah ini, 89.40% kuasa diskriminasi tercapai, ini mengesahkan kaedah yang
dicadangkan berupaya membeza bilangan pasangan pen yang signifikan. Sebagai
tambahan, komposisi dakwat biru pen mata bulat didapati homogen (RSD < 2.5%)
dan kaedah yang dicadangkan menunjukkan kebolehulangan dan keterulangan yang
baik (RSD<3.0%). Sebagai kesimpulan, HPTLC adalah satu alatan yang efektif
untuk memisahkan dakwat biru pen mata bulat.
Kata kunci: sains forensik, analisis
dakwat, kromatografi lapisan nipis berprestasi tinggi, kuasa diskriminasi, pen
mata bulat
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