Nowadays, crimes related to forged documents are increasing. Any erasure, addition or modificatio... more 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.
This manuscript aims to provide a new and non-destructive method for systematic analysis of inks ... more This manuscript aims to provide a new and non-destructive method for systematic analysis of inks on a questioned document. Ink samples were analyzed in situ on the paper substrate by micro-ATR-FTIR spectroscopy and the data obtained was processed and evaluated by a series of multivariate chemometrics. Absorbance value from wavenumbers of 2000-675 cm-1 were first processed by cluster analysis (CA), followed by principal component analysis (PCA) to form a set of new variables. Subsequently, the variables set was used for classification, differentiation and identification of 155 sample pens that comprise nine different brands. Results show that nine black ballpoint pen brands could be classified into three main groups via discriminant analysis (DA). Differentiation analyses of nine different pen brands performed using one-way ANOVA indicated only two pairs of brands cannot be differentiated at 95% confidence interval. Finally an identification flow chart was proposed to determine the brand of unknown pen inks. As a conclusion, the proposed method for extracting and creating a new variable set from infrared spectrum was evaluated to be satisfactory for systematic analysis of inks based on their infrared spectrum.
The counterfeiting of documents written with a ballpoint pen is a common phenomenon in the modern... more The counterfeiting of documents written with a ballpoint pen is a common phenomenon in the modern world. The aim of the presented study was to investigate the feasibility of applying high performance thin layer chromatography (HPTLC) to the forensic analysis of red ballpoint pen inks. Inks were extracted from writings on white office paper using methanol. The separation was performed using a solvent mixture of ethyl acetate, methanol and distilled water (70:35:30, v/v/v) as the mobile phase. The writing inks were first classified according to their main dye component. Differentiation was then attempted by taking other minor dyes into account. The results showed that the ink samples could be divided into three groups, even though similarities between the chromatograms were very high. The greatest diversity of chromatogram profiles was revealed for ink entries written using pens of different brands. The results showed that HPTLC could be an effective and reliable tool for characterizing and identifying red ballpoint pen inks.
a non-destructive method for the classification and identification of black ballpoint pen inks on... more a non-destructive method for the classification and identification of black ballpoint pen inks on a questioned document was developed. Micro-aTR-FTIR spectroscopy allowed ink samples to be analysed in situ on a paper substrate. a total of 155 sample pens encompassing forty models of nine different brands were sampled from stationary shops at Subang Jaya, Malaysia. IR spectra data was processed by a number of multivariate analysis techniques, including cluster analysis (Ca), principal component analysis (PCa) and discriminant analysis (Da). The proposed method gave satisfactory results relating to classification and identification of pen inks at the level of the brand as well as the model.
Currently, micro-ATR, one of the simplest nondestructive sampling techniques for FTiR spectroscop... more 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.
Nowadays, crimes related to forged documents are increasing. Any erasure, addition or modificatio... more 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.
This manuscript aims to provide a new and non-destructive method for systematic analysis of inks ... more This manuscript aims to provide a new and non-destructive method for systematic analysis of inks on a questioned document. Ink samples were analyzed in situ on the paper substrate by micro-ATR-FTIR spectroscopy and the data obtained was processed and evaluated by a series of multivariate chemometrics. Absorbance value from wavenumbers of 2000-675 cm-1 were first processed by cluster analysis (CA), followed by principal component analysis (PCA) to form a set of new variables. Subsequently, the variables set was used for classification, differentiation and identification of 155 sample pens that comprise nine different brands. Results show that nine black ballpoint pen brands could be classified into three main groups via discriminant analysis (DA). Differentiation analyses of nine different pen brands performed using one-way ANOVA indicated only two pairs of brands cannot be differentiated at 95% confidence interval. Finally an identification flow chart was proposed to determine the brand of unknown pen inks. As a conclusion, the proposed method for extracting and creating a new variable set from infrared spectrum was evaluated to be satisfactory for systematic analysis of inks based on their infrared spectrum.
The counterfeiting of documents written with a ballpoint pen is a common phenomenon in the modern... more The counterfeiting of documents written with a ballpoint pen is a common phenomenon in the modern world. The aim of the presented study was to investigate the feasibility of applying high performance thin layer chromatography (HPTLC) to the forensic analysis of red ballpoint pen inks. Inks were extracted from writings on white office paper using methanol. The separation was performed using a solvent mixture of ethyl acetate, methanol and distilled water (70:35:30, v/v/v) as the mobile phase. The writing inks were first classified according to their main dye component. Differentiation was then attempted by taking other minor dyes into account. The results showed that the ink samples could be divided into three groups, even though similarities between the chromatograms were very high. The greatest diversity of chromatogram profiles was revealed for ink entries written using pens of different brands. The results showed that HPTLC could be an effective and reliable tool for characterizing and identifying red ballpoint pen inks.
a non-destructive method for the classification and identification of black ballpoint pen inks on... more a non-destructive method for the classification and identification of black ballpoint pen inks on a questioned document was developed. Micro-aTR-FTIR spectroscopy allowed ink samples to be analysed in situ on a paper substrate. a total of 155 sample pens encompassing forty models of nine different brands were sampled from stationary shops at Subang Jaya, Malaysia. IR spectra data was processed by a number of multivariate analysis techniques, including cluster analysis (Ca), principal component analysis (PCa) and discriminant analysis (Da). The proposed method gave satisfactory results relating to classification and identification of pen inks at the level of the brand as well as the model.
Currently, micro-ATR, one of the simplest nondestructive sampling techniques for FTiR spectroscop... more 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.
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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.
nine different brands. Results show that nine black ballpoint pen brands could be classified into three main groups via
discriminant analysis (DA). Differentiation analyses of nine different pen brands performed using one-way ANOVA indicated only two pairs of brands cannot be differentiated at 95% confidence interval. Finally an identification flow chart was proposed to determine the brand of unknown pen inks. As a conclusion, the proposed method for extracting and creating a new variable set from infrared spectrum was evaluated to be satisfactory for systematic analysis of inks based on their infrared spectrum.
minor dyes into account. The results showed that the ink samples could be divided into three groups, even though similarities between the chromatograms were very high. The greatest diversity of chromatogram profiles was revealed for ink entries written using pens of different brands. The results showed that HPTLC could be an effective and reliable tool for characterizing and identifying red ballpoint pen inks.
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.
nine different brands. Results show that nine black ballpoint pen brands could be classified into three main groups via
discriminant analysis (DA). Differentiation analyses of nine different pen brands performed using one-way ANOVA indicated only two pairs of brands cannot be differentiated at 95% confidence interval. Finally an identification flow chart was proposed to determine the brand of unknown pen inks. As a conclusion, the proposed method for extracting and creating a new variable set from infrared spectrum was evaluated to be satisfactory for systematic analysis of inks based on their infrared spectrum.
minor dyes into account. The results showed that the ink samples could be divided into three groups, even though similarities between the chromatograms were very high. The greatest diversity of chromatogram profiles was revealed for ink entries written using pens of different brands. The results showed that HPTLC could be an effective and reliable tool for characterizing and identifying red ballpoint pen inks.