油性圆珠笔字迹书写时间鉴定的研究综述

本文追述了油性圆珠笔问世以来,字迹书写时间的检验发展过程;总结了静态法,如标准样品比对法和基准物标记法,动态法,如如溶剂萃取法、色谱法、质谱法和光谱法用于鉴定圆珠笔字迹书写时间的研究成果;展望了非破坏性方法在鉴定书写时间上的发展趋势。     

打印墨水种类鉴别的现状

本文主要论述了喷墨打印机打印墨水的组成和种类的鉴别方法,如溶解性检验、高效薄层谱法、高效液相色谱法、毛细管电泳法、光谱法等,为分析打印墨水的种类提供参考。     

签字笔墨水字迹形成时间研究综述

字迹色痕形成时间检验是法庭科学领域的热点和难点问题之一.签字笔现在已成为最常用的书写工具,签字笔墨水字迹形成时间鉴定成为字迹色痕形成时间鉴定技术的一个重要组成部分.文章对国内有关签字笔墨水字迹形成时间鉴定的文献进行了综述,介绍了用于形成时间鉴定的无损检验和有损检验方法,对各种方法的适用性和检验条件进行了简单的分析总结,以期对相关研究人员提供借鉴作用,并在各类案件的侦查、诉讼和审判中发挥作用.     

铅粉涂抹法显现被书写文字遮掩的压痕文字

对于压痕文字的检验，目前有诸多的方法，如静电吸附法、测光照相法、加强反差法等，以至于使用文检仪、图像处理系统等设备。但是，对于被书写文字遮掩的压痕文字，在不具备更先进设备的情况下，使用目前这些检验方法，并不能完全辨认压痕文字的内容，主要是因为被书写文字遮掩所致。被书写文字遮     

傅立叶变换拉曼光谱法鉴别黑色墨水的研究

采用傅立叶交换拉曼光谱法对6种黑色墨水字迹进行检验分析实验结果表明,能对黑色墨水样品进行有效的鉴别。该方法具有快速、简便、不破坏样品的特点。     

自动褪色魔术笔书写字迹的检验

近期，淘宝网上热卖一种名为“自动褪色魔术笔”的特制签名笔，其外形与普通签字笔无异，只是采用了特殊墨水。该墨水书写出来的字迹与普通签字笔没有差别，但是会因材质、温度、湿度、书写速度等差异在15分钟至3日内自然消失，肉眼在日光下观察看不出字迹。该笔主要用于纺织、手工艺等行业做记号，或用于学生字帖临摹、涂鸦等。但一些不法分子却利用“自动褪色魔术笔”的特殊性在经济领域实施违法犯罪行为。在取证或检验时，褪色后的字迹用常规照相方法较难拍摄，但利用紫外光致发光照相技术可以清晰显现消褪字迹。本文就一案例详细阐述了运用紫外光致发光照相技术拍摄，介绍检验自动褪色魔术笔褪色后的字迹的方法。     

书写时间检验方法

书写时间检验方法潘欣欣在物证检验科学技术中，书写时间的检验具有非常重要的意义。书写墨水的检验为伪造文书的侦破起着巨大的作用。牵涉巨额款项的案件包括医疗事故、虚假存款、逃避税收、遗嘱、版权纠纷、虚假保险、离婚判决、劳务纠纷和合同纠纷等都要用到这种技术确...     

异烟胼及其代谢产物检验一例

<正> 异烟肼在体内迅速被吸收和代谢,因此在这类中毒案件鉴定中,检验异烟肼的代谢产物比检验其原体更为重要。对异烟肼的代谢产物文献中报导不一,主要有乙酰异烟肼、异烟酸、乙酰肼和二乙酰肼等,其中报导最多的是乙酰异烟肼。目前还未见到同时检出这几种代谢产物的报导。异烟肼及其代谢产物的检验方法很多,如紫外吸收光谱法、荧光光谱法、极谱法、原子吸收光谱法、     

化学显色法分析喷墨打印机黑色墨水的种类

目的建立化学显色法检验喷墨打印机字迹色痕的方法。方法选用不同的试剂或混合试剂,对22种不同品牌的喷墨打印黑色墨水的溶解性及与不同试剂的颜色反应进行观察。结果不同品牌的喷墨打印机黑色墨水的溶解性不同,与不同试剂作用会显现不同的颜色。结论化学显色法快速、简便,可用于现场的快速检验。     

薄层色谱法鉴别黑色中性笔色痕的种类

黑色中性笔墨水主要由溶剂、色料、增稠剂、稳定剂和其他添加剂等组成,不同厂家或同厂家不同牌号中性笔墨水的成分不同,尤其是色料差别较大,这为中性笔墨水的种类鉴别提供了依据。本文利用数理统计中的均匀设计法和正交设计法安排试验,建立了一种可用于黑色中性笔色痕种类鉴别的方法:用N,N-二甲基甲酰胺作为黑色中性笔色痕的提取剂,四氢呋喃:甲醇:1,2-二氯乙烷:氯仿=30:15:5:7为展开剂的薄层色谱分析法。     

Application of the micro-FTIR spectroscopy, Raman spectroscopy and XRF method examination of inks

In routine examination of inks on questioned documents non-destructive analytical methods, such as microscopic and optical techniques are applied first. However, they are often insufficient to identify the inks used for the preparation of the document. In such cases, it is necessary to apply chemical methods that normally cause partial destruction of the examined material. The aim of this work was to evaluate the possibility of discrimination between inks by the use of spectrometric methods, i.e. micro-FTIR spectroscopy, Raman spectroscopy and XRF. About 70 samples of blue and black ballpoint pen and gel inks were examined. It was found that about 90% of the samples of the same type and colour could be distinguished using these methods.     

Application of Raman spectroscopy in forensic investigation of questioned documents involving stamp inks

Stamp pad inks from different manufacturers across India have been analyzed to investigate the feasibility of Raman scattering as a tool for forensic analysis of questioned documents involving stamp inks. Nine different stamping inks were analyzed by both Raman spectroscopic and HPTLC methods. The results demonstrate the effectiveness of these methods in classifying the investigated stamping inks based on their spectral pattern and HPTLC chromatogram. Raman scattering tool was able to determine the sequence of heterogeneous intersection strokes involving a blue stamp pad ink and other writing instruments, such as ballpoint pen ink (red and black), pencil and laser printer toner. However, this method was unable to resolve the exact sequencing for the intersection strokes involving investigated stamp ink and blue ballpoint ink or gel pen ink (all colors).     

Identification of colorants in pigmented pen inks by laser desorption mass spectrometry

Pigments are rapidly replacing dyes as colorants in pen and printer inks, due to their superior colors and stability. Unfortunately, tools commonly used in questioned document examination for analyzing pen inks, such as TLC, cannot be used for the analysis of insoluble pigments on paper. Laser desorption mass spectrometry is demonstrated here as a tool for analyzing pigment-based pen inks. A pulsed nitrogen laser can be focused onto a pen stroke from a pigmented ink pen on paper, and positive and negative ions representative of the pigment can be generated for subsequent mass spectrometric analysis. Targeted pens for this work were a set of Uni-ball 207 pigmented ink pens containing blue, light blue, orange, green, violet, red, pink, and black inks. Copper phthalocyanine was identified as the pigment used to make both blue inks. A mixture of halogenated copper phthalocyanines were identified in the green ink. Unexpectedly, the pink ink was found to contain a red pigment, Pigment Red 12, treated with a mixture of water-soluble dyes. Each sample yielded ions representative of the pigments present.     

Minimum requirements for application of ink dating methods based on solvent analysis in casework

Several ink dating methods based on solvents analysis using gas chromatography/mass spectrometry (GC/MS) were proposed in the last decades. These methods follow the drying of solvents from ballpoint pen inks on paper and seem very promising. However, several questions arose over the last few years among questioned documents examiners regarding the transparency and reproducibility of the proposed techniques. These questions should be carefully studied for accurate and ethical application of this methodology in casework. Inspired by a real investigation involving ink dating, the present paper discusses this particular issue throughout four main topics: aging processes, dating methods, validation procedures and data interpretation. This work presents a wide picture of the ink dating field, warns about potential shortcomings and also proposes some solutions to avoid reporting errors in court.     

An evaluation of matching unknown writing inks with the United States International Ink Library

Utilizing a database of standards for forensic casework is a valuable resource. Undoubtedly, as more standards (and corresponding information about the specimens) are collected, there is a greater certainty of identification when a questioned and a known item cannot be distinguished after a series of analyses. The United States Secret Service and the Internal Revenue Service National Forensic Laboratory jointly maintain the largest known forensic collection of writing inks in the world, which is comprised of over 8500 ink standards collected worldwide, dating back to the 1920s. This study was conducted to evaluate the reliability of matching arbitrarily purchased pens with known inks from a database. One hundred pens were randomly obtained from a variety of sources and their respective ink compositions were compared with standards. Eighty-five of the inks were determined to be suitable for comparison utilizing optical examinations and thin-layer chromatography. Three of the inks did not match any of the specimens on record; one of these inks was similar to an ink from an identical brand of pen that was in the database, but had a modified formulation.     

Forensic discrimination of blue ballpoint pen inks based on thin layer chromatography and image analysis

This article aims to provide a new and fast method for differentiation of inks on a questioned document. The data acquisition was carried out by designing specific image analysis software for evaluating thin layer chromatograms (TLC-IA). The ink spot was extracted from the document using methanol and separated by TLC using plastic sheet silica gel 60 without fluorescent indicator, and a mixture of ethyl acetate, ethanol, and water (70:35:30, v/v/v) as mobile phase. To discriminate between different pen inks, new software was designed on the basis of intensity profile of red, green, and blue (RGB) characteristic. In practice, after development of chromatogram, the chromatograms were scanned by ordinary office scanner, intensity profiles of RGB characteristics on the development straight of each sample were produced and compared with the mentioned software. RGB profiles of ballpoint inks from various manufacturers showed that the patterns in most cases were distinctly different from each other. This new method allowed discriminating among different pen inks with a high reliability and the discriminating power of 92.8%. Blue ballpoint pen inks of 41 different samples available on the local market were successfully analyzed and discriminated.     

Systematic analysis of bulk blue ballpoint pen ink by FTIR spectrometry

A classifying method on bulk blue ballpoint pen ink has been studied by Fourier transform infrared (FTIR) spectroscopy. By using this method, a total of 108 blue ink samples have been divided into two groups depending on their main component. Spectral characteristics of these inks such as frequency and absorbance are described by way of artificial intelligence of pattern recognition, and 35 subgroups from the 108 inks are distinguished by their correlation coefficient (lambda). Under heat or exposure to ultraviolet light a mode of change in the age of the inks has been obtained. This approach has provided a reliable and nondestructive method for the characterization of bulk ballpoint writing ink, and more importantly, it might be a basis for dating of the blue ballpoint pen ink.     

Dynamic of the ageing of ballpoint pen inks: quantification of phenoxyethanol by GC-MS.

The ageing process of some inks were studied to evaluate whether it is possible to date them. We used gas chromatography coupled with mass spectrometry to measure the evaporation of volatile components. The selected approach thus follows the disappearance of one ink volatile component (phenoxyethanol) as a function of time. The ink ageing curve represents the ratio of an evaporating compound to a stable compound of ink according to time. The results obtained are thus independent of the quantity of ink sampled for analysis. We obtained for two pens, containing two different inks, a curve highlighting an exponential decrease of the evaporating compound. By fitting these curves we determined the limitations of dating a ballpoint pen ink. Two distinct behaviours were observed in two distinct modes, the first called 'fast mode' and the second called 'slow mode'. In order to try to explain the phenomenon, the studies were based on solvent diffusion theory in complex matrix (such as polymer on varnish). Calculations from certain parameters showed an extremely fast evaporation of ink solvents, as well as varying behaviour depending on the paper used. The results showed that it is not possible to date ballpoint pen inks with this method in document examination casework.     

The detection of multiply charged dyes using matrix-assisted laser desorption/ionization mass spectrometry for the forensic examination of pen ink dyes directly from paper

Abstract:  Laser desorption mass spectrometry (LDMS) is emerging as a technique for questioned document examination. Its use is limited to detecting ink dyes that are neutral or singly charged. Several inks contain dyes that are multiply charged and LDMS cannot be employed for their identification. We have successfully detected >20 polyionic dyes that can be used in the manufacture of inks using matrix-assisted laser desorption/ionization (MALDI) MS, directly from paper, with the matrix, 2-(4-hydroxyphenylazo)benzoic acid (HABA), and the additive, diammonium hydrogen citrate (DAHC). For example, Acid Violet 49, a charged dye containing one positively-charged site and two negatively charged sulfonate groups, cannot be detected by LDMS, but forms intact, singly charged ions in the MALDI MS experiment. The method described is also useful for identifying multiply charged dye mixtures that are used in modern pen inks.     

Analysis of Indian blue ballpoint pen inks tagged with rare-earth thenoyltrifluoroacetonates by inductively coupled plasma-mass spectrometry and instrumental neutron activation analysis

Characterization and assessment of inks on sensitive documents for absolute/relative age determination is the challenging forensic problem in spite of practical difficulties. Tagging of ballpoint pen ink with suitable taggant(s) is a unique method to come out with definitive inferences on the detection of forgery in documents written with ballpoint pens. Selection of a proper taggant primarily depends on sensitivity of analytical determination and their absence in normal varieties of ink used for document writing. Rare-earth elements, from all technical considerations can be potential taggant(s) for inks. To ensure more compatibility with ink, 13 rare-earth thenoyltrifluoroacetonate chelates were prepared and characterized. The ballpoint pen inks were tagged with rare-earth thenoyltrifluoroacetonate chelates individually at about 1-100 ppm level depending on sensitivity of element under suitable optimized experimental conditions and instrumental sensitivity. Aliquots of such tagged ink having varying amounts of taggants were analyzed by ICP-MS and INAA. Satisfactory recoveries and a good linear relationship of intensity (signal) against concentrations/amounts were observed. Under the optimized experimental conditions, the detection limits were worked out. This study of tagging metal ions in combination with ICP-MS and NAA as an analytical tool can allow to draw various combination options based on different rare-earth chelates as suitable materials for tagging of ballpoint pen inks for absolute/relative age determination to aid in document related crime examination. The advantages and limitations of proposed analytical techniques are discussed.