Thesis-2009-Alsuidan.pdf (6.42 MB)
Identification of ink degradation products by LC–MS
thesis
posted on 2018-08-15, 10:33 authored by Abdulelah AlsuidanThe aging processes of ink dyes in ballpoint inks were determined using
modem chromatographic and spectrometric methods with their possible application.
Two main methods were applied IP–HPLC method with photodiode array detection
for ink dyes separation and LC–MS method for the identification of ink degradation
products as a function of age, for this purpose the two methods were developed and
validated. The aging processes of standard dyes as reference substances at different
conditions (light and heat) were investigated. These processes were used then on ink
entries on paper. Dye components and their degradation products were successfully
separated and identified by their retention time, UV-visible absorption profiles and
mass spectra. Different blue ballpoint inks were identified and discriminated by
comparing their relative peaks areas (RPA) to obtain the aging profiles. Moreover,
other types of ink (gel pens, fibre tips and different colours) were also analysed and
discriminated successfully by the developed method. In addition, several months’
entries from multiple inks entries exposed to normal sunlight and samples stored in
the dark were compared. A typical and expected degradation of ink dyes was
characterized by the de-alkylation process (loss of CH2– or CH2–CH3 groups). Crystal
violet and Victoria blue dye groups, two major dyes used in ballpoint ink industries
were thoroughly investigated.
In this work, mass spectrometric methods were developed and validated to describe
the ageing mechanism of ballpoint ink dyes. Furthermore, factors influencing the
aging process (heat, light, natural aging factors) were studied. For real forensic cases
the storage conditions of the paper and type of pen used should be known.
Funding
Saudi Arabia, Ministry of Interior, Forensic Science Department.
History
School
- Science
Department
- Chemistry
Publisher
© Abdulelah AlsuidanPublisher statement
This work is made available according to the conditions of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) licence. Full details of this licence are available at: https://creativecommons.org/licenses/by-nc-nd/4.0/Publication date
2009Notes
A Doctoral Thesis. Submitted in partial fulfilment of the requirements for the award of Doctor of Philosophy at Loughborough University.Language
- en