Organic and inorganic discrimination of ballpoint pen inks by ToF-SIMS and multivariate statistics

Denman, John A.; Skinner, William; Kirkbride, K. Paul; Kempson, Ivan M.

doi:10.1016/j.apsusc.2009.09.066

Cited by 73 publications

(43 citation statements)

References 32 publications

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“…The organic signals will be significantly im- proved, for example, utilizing a C 60 [30,31], Bi cluster [32], or Au cluster source [33], and coupled with multivariate statistical techniques [34,35]. Such sources provide greater ionization efficiency and yields of larger and more indicative fragments [36].…”

Section: Discussionmentioning

confidence: 99%

Use of TOF-SIMS to study adsorption and loading behavior of methylene blue and papain in a nano-porous silicon layer

Kempson

Barnes

Prestidge

2010

J. Am. Soc. Mass Spectrom.

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TOF-SIMS was applied to study the cross-sectional distribution of methylene blue and papain in porous silicon layers. Elemental and molecular information were used to study their distributions in the porous region and the chemistry of their adsorption. Methylene blue (MW ϭ 284 Da) [4], and the delivery of active pharmaceutical ingredients [5,6]. The ongoing interest in pSi for use as a therapeutic delivery system is due to the large internal surface area available, the readily modified surface chemistry [7] and, in particular, the excellent in vivo biodegradation and biocompatibility (low toxicity) of the silicon substrate, hydrolysing to form orthosilicic acid, which is readily excreted [8]. The loading dynamics of molecules into a pSi matrix is dependent on wetting and the size of the pores. Likewise, the interaction between a loaded molecule and the pSi substrate is of interest, particularly in the case of protein based therapeutics, whose bioactivity is dependent on remaining in a specific 3D conformation.TOF-SIMS analysis provides information regarding elemental and molecular species present in a sample surface (i.e., within 1-1.5 nm) with high mass resolution (up to ϳ10,000 m/⌬m) and spatial resolution for imaging (ϳ1 micron). Molecular and elemental information is obtained for organic and inorganic materials providing a powerful technique to image organic compounds associated with inorganic substrates or vice versa [9,10]. This has been demonstrated by imaging solid-state pharmaceutical formulations [11][12][13][14], however, to date this has not been extended to porous silicon substrates.In this study, TOF-SIMS was used to map the distribution of methylene blue and papain across porous silicon layers after loading from aqueous solution. Methylene blue (C 16 H 18 N 3 S ϩ , MW ϭ 284.12 g/mol) is a relatively small organic dye molecule commonly used in adsorption studies and can be considered analogous to therapeutic molecules. A molecular mass of 284 g/mol is within a reasonable mass range for a TOF-SIMS' Ga ϩ primary ion beam and can be easily and uniquely identified without interference or confusion from spectral peaks originating from the silicon substrate or in the instance of organic contamination. This molecule was chosen for its convenience, and to assess the ability to use smaller organic fragments to reflect the distribution of the molecule of interest. This is important to be able to extend this work to studying larger molecules, such as proteins and enzymes of pharmaceutical interest, which will not provide a molecular ion in TOF-SIMS. In contrast to methylene blue, papain is a much larger molecule, detailed elsewhere [15], comprising 212 residue units in two domains, giving a molecular weight of 23,406 g/mol. Papain is a cysteine protease hydrolase enzyme present in papaya. This molecular weight is far greater than can be detected with TOF-SIMS, however, fragmentation products can be detected. Smaller organic fragments can be compared with the distribution of methylene blue to investigate si...

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Section: Discussionmentioning

confidence: 99%

Use of TOF-SIMS to study adsorption and loading behavior of methylene blue and papain in a nano-porous silicon layer

Kempson

Barnes

Prestidge

2010

J. Am. Soc. Mass Spectrom.

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“…The three degradation ions that belong to Crystal Violet in Table 2 have resulted from natural aging. A. Denman et al 8 when analyzing a blue BIC pen. 44 Basic Yellow 2 was also confirmed by J.…”

Section: Nanospray Solvent Chemistrymentioning

confidence: 99%

“…The analyses of ink entries on these falsified documents include looking for added ink to the original written ink entry, thus, changing the meaning of the text (e.g., changing the number four into a nine). Denman et al 8 analyzed 24 blue ballpoint pens using time-of-flight (ToF)-SIMS and prepared the samples by drawing a 3 cm line on paper with each spectral analysis performed over a 100 × 100 μm raster area. 1 Material evidence found at crime scenes must be kept in its pristine state in order to preserve its evidentiary value.…”

Section: Introductionmentioning

confidence: 99%

Investigation of falsified documents via direct analyte-probed nanoextraction coupled to nanospray mass spectrometry, fluorescence microscopy, and Raman spectroscopy

Huynh

Williams

Golden

et al. 2015

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Microscopy with direct analyte-probed nanoextraction coupled to nanospray ionization mass spectrometry (DAPNe-NSI-MS) is a direct extraction technique that extracts ultra-trace amounts of analyte. It has been proven to extract ink from documents with little to no physical or chemical footprint. In this study, DAPNe has been coupled to Raman spectroscopy, fluorescence microscopy, and NSI-MS to determine if an ink entry from a document was falsified. A handwritten number was altered using a different ink pen to test if the aforementioned techniques could discriminate the original number from the altered number, qualitatively and/or quantitatively. Chemical species from part of the original number, altered number, and a point at which both inks intersect were successfully differentiated by all techniques when using different pens. DAPNe coupled to fluorescence microscopy and Raman spectroscopy was not able to discriminate the forged ink entry when the exact same pen was used to modify the text (due to the same ink formula). However, DAPNe-NSI-MS successfully discerned that the pen was dispensed on different days by quantitating the oxidation process.

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“…Around 80 % of the questioned documents contain ballpoint pen ink [2]. On the other hand, the forensic analysis of ballpoint pen inks is a frequently encountered at questioned documents examination and its contribution towards solving crimes is significant.…”

Section: -2506mentioning

confidence: 99%

Fast and Simple Forensic Red Pen Ink Analysis Using Ultra-Performance Liquid Chromatography (Uplc)

Lee¹,

Ying²,

Fuad³

et al. 2016

MJAS

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Ultra-performance liquid chromatography (UPLC) is more effective than high performance liquid chromatography in terms of analysis speed and sensitivity. This paper presents a feasibility study on forensic red pen inks analysis using UPLC. A total of 12 varieties of red ballpoint pen inks were purchased from selected stationary shop. For each variety, four different individual pens were sampled to provide intra-variability within a particular variety of pen. The proposed approach is very simple that it only involved limited analysis step and chemicals. A total of 144 chromatograms were obtained from red ink entries extracted with 1.5 mL 80 % (v/v) acetonitrile. Peaks originated from pen inks were determined by comparing the chromatograms of both blank paper and blank solvent against that of ink samples. Subsequently, one-way ANOVA was conducted to discriminate all 66 possible pairs for red pen inks. Results showed that the proposed approach giving discriminating power of 95.45 %. The outcome of the study indicates that UPLC could be a fast and simple approach to red ballpoint pen inks analysis.Keywords: forensic ink analysis, ballpoint pen inks, ultra-performance liquid chromatography Abstrak Kromatografi cecair berprestasi Ultra (UPLC) adalah lebih berkesan dari kromatografi cecair berprestasi tinggi dari segi kelajuan analisis dan kepekaan. Kertas ini mempersembahkan kajian kebolehlaksanaan pada analisis dakwat pen merah menggunakan UPLC. Sebanyak 12 jenis dakwat pen mata bulat merah dibeli dari kedai alat tulis yang terpilih. Untuk setiap jenis, empat batang pen telah disampel untuk memberi maklumat tentang intra-variasi bagi suatu jenis pen. Pendekatan yang dicadangkan adalah mudah kerana ia hanya melibatkan langkah analisis dan bahan kimia yang terhad. Sejumlah 144 kromatogram telah diperolehi dari dakwat tulisan merah yang diekstrak dengan 1.5 mL 80 % (v/v) asetonitril. Puncak yang berasal dari dakwat pen ditentukan melalui perbandingan antara kromatogram kertas kosong dan pelarut kosong dengan yang diperolehi dari sampel dakwat. Seterusnya, ujian ANOVA sehala telah dijalankan untuk membezalayan kesemua 66 pasangan dakwat pen merah yang terbentuk. Keputusan menunjukkan pendekatan yang dicadangkan memberi 95.45 % kuasa pembezalayan. Hasil kajian ini menunjukkan UPLC dapat dijadikan satu pendekatan yang cepat dan mudah untuk analisis dakwat pen mata bulat merah.

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Organic and inorganic discrimination of ballpoint pen inks by ToF-SIMS and multivariate statistics

Cited by 73 publications

References 32 publications

Use of TOF-SIMS to study adsorption and loading behavior of methylene blue and papain in a nano-porous silicon layer

Use of TOF-SIMS to study adsorption and loading behavior of methylene blue and papain in a nano-porous silicon layer

Investigation of falsified documents via direct analyte-probed nanoextraction coupled to nanospray mass spectrometry, fluorescence microscopy, and Raman spectroscopy

Fast and Simple Forensic Red Pen Ink Analysis Using Ultra-Performance Liquid Chromatography (Uplc)

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