The Analysis of Ballpoint Inks with APCI-MS after Fading with Light, Hydrogen Peroxide and Sodium Hypochlorite Bleach by Claire Williamson A thesis submitted in partial fulfilment for the requirements for the degree of Doctor of Philosophy at the University of Central Lancashire September 2015 Table of Contents Table of Figures ............................................................................................. iv Acknowledgments ......................................................................................... xii Abstract ........................................................................................................ xiv Introduction ..................................................................................... 1 1.1 Forensic Science ................................................................................... 1 1.1.1 Document Analysis .......................................................................... 1 1.2 History of Writing Ink ................................................................................. 4 1.2.1 Ballpoint Pen Ink Composition ............................................................ 5 1.3 Ink Aging ................................................................................................. 11 1.3.1 Dye Degradation ............................................................................... 12 1.3.2 Ink Dating .......................................................................................... 15 1.4 Ink Analysis ............................................................................................. 18 1.5 Instrumental ............................................................................................. 23 1.5.1 Filtered Light Examination ................................................................ 23 1.5.2 Mass Spectrometry ........................................................................... 25 1.5.3 Atmospheric Pressure Chemical Ionisation ...................................... 27 1.6 Aims ........................................................................................................ 30 Experimental Techniques .............................................................. 31 2.1 Sampling ................................................................................................. 31 2.1.1 Sample Preparation .......................................................................... 33 2.2 Filtered Light Experimental Details .......................................................... 35 2.2.1 Filtered Light Materials and Methods ................................................ 35 2.3 APCI – MS Experimental Details ............................................................. 35 2.3.1 APCI-MS Materials and Methods ...................................................... 35 Identification of Ballpoint Ink Dyes................................................. 38 3.1 Fresh Dye Standards .............................................................................. 38 3.2 Fresh Ink Samples .................................................................................. 40 i 3.3 Validation of Instrumentation ................................................................... 48 3.4 Discussion and Conclusions .................................................................... 50 Analysis of Blue Inks ..................................................................... 52 4.1 Degradation Products .............................................................................. 52 4.2 Photodegradation .................................................................................... 56 4.2.1 Photofading of Dye Standards in Solution ........................................ 56 4.2.2 Photofading of Dye Mixtures in Solution ........................................... 61 4.2.3 Photofading of Inks on Paper ............................................................ 70 4.2.4 Comparison of Fading with No Light ................................................. 77 4.3 Bleaching with Hydrogen Peroxide .......................................................... 78 4.3.1 Bleaching of Dye Standards ............................................................. 78 4.3.1.1 In the Dark ..................................................................................... 78 4.3.1.2 In the Light ..................................................................................... 83 4.3.2 Bleaching of Dye Mixtures in Solution ............................................... 89 4.3.3 Bleaching of Inks on Paper ............................................................... 95 4.4 Bleaching with Sodium Hypochlorite ..................................................... 104 4.4.1 Bleaching of Dye Standards ........................................................... 104 4.4.1.1 In the Dark ................................................................................... 104 4.4.1.2 In the Light ................................................................................... 114 4.4.2 Bleaching of Inks on Paper ............................................................. 124 4.5 Discussion and Conclusions .................................................................. 129 4.5.1 Photofading ..................................................................................... 129 4.5.2 Bleaching with Hydrogen Peroxide ................................................. 131 4.5.3 Bleaching with Sodium Hypochlorite. .............................................. 135 Analysis of Black Inks .................................................................. 138 5.1 Degradation Products ............................................................................ 138 5.2 Photodegradation .................................................................................. 139 5.2.1 Photofading of Dye Standards in Solution ...................................... 139 ii 5.2.2 Photofading of Dye Mixtures in Solution ......................................... 143 5.2.3 Photofading of Inks on Paper .......................................................... 148 5.2.4 Comparison of Fading with No Light ............................................... 154 5.3 Bleaching with Hydrogen Peroxide ........................................................ 157 5.3.1 Bleaching of Dye Standards ........................................................... 157 5.3.1.1 In the Dark ................................................................................... 157 5.3.1.2 In the Light ................................................................................... 161 5.3.2 Bleaching of Dye Mixtures in Solution ............................................. 167 5.3.3 Bleaching of Inks on Paper ............................................................. 171 5.4 Bleaching with Sodium Hypochlorite ..................................................... 179 5.4.1 Bleaching of Dye Standards ........................................................... 179 5.4.1.1 In the Dark ................................................................................... 179 5.4.1.2 In the Light ................................................................................... 186 5.4.2 Bleaching of Inks on Paper ............................................................. 192 5.5 Discussion and Conclusions .................................................................. 197 5.5.1 Photofading ..................................................................................... 197 5.5.2 Bleaching with Hydrogen Peroxide ................................................. 199 5.5.3 Bleaching with Sodium Hypochlorite Bleach ................................... 202 Discussion and Conclusions ....................................................... 206 iii Table of Figures Figure 1.1 Cellulose Structure............................................................................. 3 Figure 1.2 Positions of Functional Groups .......................................................... 9 Figure 1.3 Structures of Solvents found in Ballpoint Pen Inks43 ........................ 10 Figure 1.4 Structures of Resins found in Ballpoint Pen Ink44 ............................ 11 Figure 1.5 Mechanism of Demethylation of a Triphenylmethane dye ............... 13 Figure 1.6 Oxidative Cleavage of Basic Violet 3 by Singlet Oxygen ................. 14 Figure 1.7 Energy Level diagram showing Fluorescence Emission .................. 24 Figure 1.8 Schematic of APCI system .............................................................. 28 Figure 1.9 Photograph of APCI-MS equipment used ........................................ 29 Figure 2.1 Schematic of Sample preparation .................................................... 36 Figure 3.1 APCI-MS Spectra for Dye Standards ............................................... 39 Figure 3.2 APCI-MS Spectra of Blue Ballpoint Pens ......................................... 43 Figure 3.3 APCI-MS Spectra of Black Ballpoint Pens ....................................... 44 Figure 3.4 APCI-MS Spectra of Red Ballpoint Pens ......................................... 46 Figure 3.5 APCI-MS Spectra of Green and Purple Ballpoint Pens.................... 47 Figure 4.1 Aging Curves for dye standards a: Basic Violet 3 b: Basic Violet 1, c: Benzophenones for BV3 d: Benzophenones for BV1 during Photofading ........ 57 Figure 4.2 Aging Curves for Benzophenone Products from Basic Violet 3 and Basic Violet 1 during Photofading ....................................................................