高效液相色谱法鉴别蓝色签字笔墨水的种类

目的通过对签字笔字迹成分进行检验，达到对签字笔成分进行分离并对签字笔种类进行鉴定的目的。方法使用高效液相色谱法对蓝色签字笔字迹色痕中的色料成分进行分析，并依据分析结果对墨水的种类划分，同时考察了纸张的背景影响、最小用样量以及实验结果的重现性。结果22种蓝色签字笔样品均可以实现区分。结论本研究对实际应用有较大参考价值。     

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.     

显微分光光度法检验蓝黑墨水字迹形成时间的适用性研究

本文利用显微分光光度法对八种不同品牌的蓝黑墨水字迹随时间变化的规律进行了研究,目的是考察该方法在鉴定蓝黑墨水字迹形成时间方面的适用性。实验分析了自然老化条件下的蓝黑墨水字迹在300~700nm波长范围内的反射光谱曲线,并计算墨迹与纸张的色差(△E),考查了△E与字迹形成时间的相关性,结果表明利用显微分光光度法测定蓝黑墨水字迹形成时间具有一定可行性。     

透射光谱成像技术检验黑色签字笔涂抹掩盖字迹研究

目的 对透射光谱成像技术和反射光谱成像技术检验黑色签字笔间涂抹掩盖字迹进行比较研究,探寻一种无损、高效、直观的黑色签字笔涂抹掩盖字迹的显现方法,提高黑色签字笔间涂抹掩盖字迹显现效率。方法根据不同黑色签字笔油墨物质成分不同,不同物质对光的透射率各异的特征,在相同条件下使用反射光谱成像技术与透射光谱成像技术分别对多个黑色签字笔间涂抹掩盖字迹实验样本进行检验。本文将显现效果分为可显现和不可显现两类。分类标准为从未看过原字迹的非文检人员是否可以辨认出被涂抹掩盖字迹。结果 利用透射光谱成像检验系统检验黑色签字笔涂抹掩盖字迹样本,306个样本中,可显现的有231个,不可显现的75个,显效率为75.49%;反射光谱成像技术检验306个样本,其中可显现的有159个,不可显现的有147个,显现效率为51.96%。实验结果表明透射光谱成像检验黑色签字笔涂抹掩盖字迹的显现率高于反射光谱成像检验的检验。结论 除了无法显现原字迹与涂抹掩盖笔迹的油墨物质成分、浓度以及组成配比相同或相近的样本之外,透射光谱成像技术能检验常规的光谱成像技术无法显现的黑色签字笔间涂抹掩盖字迹,其显现效果和效率都优于反射光谱成像技术,是一种高效的显现方法 ,可以应用于刑事物证检验领域。     

基于银胶表面增强拉曼光谱检验蓝色书写字迹初探

目的用基于银胶的表面增强拉曼光谱技术检验蓝色签字笔字迹。方法取4种常见不同牌号的蓝色签字笔在其字迹上滴加微量银胶,用显微共焦拉曼光谱仪进行检验。结果不同品牌的蓝色签字笔字迹的表面增强拉曼光谱不同。结论基于银胶的表面增强拉曼光谱技术可用于纸张上蓝色签字笔字迹的检验。     

透析法测定钢笔墨水字迹的书写时间

本文通过最新研发的透析液,根据透析的原理,对书写在不同种类纸张上的不同种类的钢笔墨水字迹进行了书写时间测定。在基本保证透析液的浓度、厚度和钢笔字迹色料浓淡一致的基础上,考查了不同种类钢笔墨水字迹和不同种类纸张对透析结果的影响,得出了一般性规律,并介绍了该项新技术的原理和操作方法。     

光谱成像检验同种同色涂抹掩盖字迹研究

目的建立一种无损、灵敏、直观的同种同色涂抹掩盖字迹的显现方法。方法依据涂抹掩盖字迹油墨物质的同色异谱特征,利用可见光滤波型多光谱成像检验系统进行检验。结果黑色圆珠笔、蓝色圆珠笔、黑色签字笔和蓝色签字笔相互涂抹掩盖形成的同种同色涂抹掩盖样本,利用可见光滤波型多光谱成像检验系统进行检验,显效率分别为90.5%、69.1%、49.5%、78.6%,显现效果良好。结论多光谱成像技术可以显现同种同色涂抹掩盖字迹,且具有良好的显现效果。     

基于HPLC的三芳甲烷类染料字迹人为老化的实验研究

目的对蓝色圆珠笔字迹在经过紫外光源老化后的独特特征进行研究,建立确认紫外灯照射的人为老化文件的方法。方法本文以蓝色圆珠笔字迹为研究对象,蓝色圆珠笔中的三芳甲烷类染料在紫外灯的照射下会吸收光子的能量加速其老化脱甲基的反应,通过适当的假设可以推导出其老化程度随时间变化的老化方程,由于目前紫外灯管几乎全部是线型结构,建立合适的坐标系,假设线型灯管能量分布均匀,且紫外线以球面波的形式传播出去,可以计算出纸面上任意一点的能量,通过纸张表面不同位置的三芳甲烷类染料的老化程度的不同来区别自然老化文件与紫外灯人为老化文件的不同。结果经过实验发现对于紫外灯人为老化文件来说甲基紫初始含量比上老化后含量的对数值与紫外灯对于该点的能量的辐出的比值为一个常数K,该K值稳定,浮动范围小,线性关系的置信度大于99%,可以认为两个参数之间存在显著地线性关系,可以证明对于老化方程的推导和能量密度分布函数的推导合理符合实际,对于自然老化文件来说则不存在这种规律。结论可以利用这种特殊的分布规律构建一个衡量这种分布的函数来定量地确认紫外灯照射的人为老化文件。     

紫外-可见光谱法研究蓝色圆珠笔色痕自然老化规律

目的论述自然老化下蓝色圆珠笔色痕中染料成分的变化规律。方法利用UV-VIS光谱对圆珠笔文字色痕中染料成分相对于铜酞菁的变化进行实验。结果得到染料与铜酞菁吸光度之比随老化时间变化的数据和曲线。结论利用UV-Vis光谱研究文件制成时间是可行的,为书写时间的鉴定拓展了思路。     

中性墨水笔墨迹中甘油成分的气相色谱分析及历时性变化初探

目的对中性墨水笔墨迹中甘油成分和随时间变化规律进行研究。方法利用气相色谱法分析了含有甘油溶剂成分的中性墨水笔字迹墨迹,并对甘油成分含量相差较大的字迹样本的变化规律进行了研究。结果得到了3种字迹墨迹中甘油成分随字迹形成时间变化的关系曲线。结论曲线变化规律表明,书写时间6个月的中性墨水笔墨迹中甘油成分的含量变化出现拐点,6个月以后甘油成分的含量基本趋于不变。     

Changes in composition of ballpoint pen inks on aging in darkness

A method for comparison of the relative age of ink entries written by the same ballpoint pen on documents stored in darkness is presented. Inks were extracted from the document and analyzed by HPLC (high performance liquid chromatography). On aging, changes in the chemical composition of the inks were noted. These changes were similar to those observed when inks were exposed to light or heat. The aging was followed by using ternary diagrams constructed for dyes generally present in blue-colored inks--Crystal Violet, Methyl Violet, and Tetramethyl Para Rosaniline. The procedure is applicable for relative dating of ink entries in diaries, notebooks, etc., where often several ink entries are written by the same ink. However, a prolonged exposure of the document to daylight and/or artificial light (light from fluorescent tubes) as well as to extensive heat will render the whole procedure inapplicable. An example of the use of the proposed method in casework is given.     

HPLC analysis of ballpoint pen inks stored at different light conditions

A method for comparison of ink entries on documents stored in different light conditions is presented. Various blue inks were exposed to light, both daylight and artificial light from fluorescent tubes. Inks were then extracted from the document and analyzed by HPLC (high performance liquid chromatography). Significant changes in composition were noted on exposure to light. These changes were followed by using ternary diagrams constructed for dyes generally present in blue-colored inks--Crystal Violet, Methyl Violet, and Tetramethyl Para Rosaniline. Also, the amount of the various compounds formed by decomposition of these dyes on exposure to light was measured and employed for comparison of inks. An example of the use of the proposed method in casework is given.     

光照人工老化原子印油色痕的分析

通过高效液相色谱法对光照人工老化后的原子印章色痕中的主要组分——颜料与油脂进行分析。寻找研究这些组分随时间变化的规律。为原子印章色痕形成时间的深入研究提供条件。     

文检仪显现同种同色掩盖字迹条件的初探

目的研究运用文检仪显现同种同色掩盖字迹的显出条件。方法以黑色签字笔为例,依据不同型号笔的油墨在不同光源下的荧光性质和红外吸收能力的差异,利用文检仪进行分析检验。结果只有在一定条件下被掩盖字迹才能被显出。结论在LUMI=IR红外荧光（兰光）下,只能显现激发荧光的油墨掩盖不能激发荧光的油墨的字迹和激发荧光能力弱的油墨掩盖激发荧光能力强的油墨的字迹;在红外吸收光和365nm长波紫外表面光下,只能显现颜色浅的油墨掩盖颜色深的油墨的字迹。     

A study to investigate the evidential value of blue gel pen inks

The aim of this project was to investigate the evidential value of blue gel pen inks in Europe. For this purpose, 33 blue gel pen inks, of different brands and models, representative of those available on the European market at the time of the study, were analyzed using three techniques: filtered light examination (FLE), Raman Spectroscopy (RS), and scanning electron microscopy (SEM). First, after visual examination (naked eye and stereo microscope), it was possible to classify the 33 inks into three groups described as: milky, metallic, and normal. This paper describes in detail the results obtained for the normal gel pen group. The ability of the techniques to discriminate gel inks between and within brands varied. The results indicated that RS and SEM were more discriminating than FLE. The greatest degree of differentiation was achieved when using a combination of RS and SEM techniques (discriminating power = 0.91). This study also highlights some problems concerning the identification of the brand of a gel pen from a written text.     

书写材料的无损检验系统研究

本研究运用显微分光光度仪、文件检验仪和傅立叶变换拉曼光谱仪三种方法,分别对在中国市场上收集的不同厂家、牌号、型号的35种黑墨水、20种蓝黑墨水、22种蓝墨水、49种黑色墨水笔、30种蓝色墨水笔、45种黑色圆珠笔、和50种蓝色圆珠笔等七组样品进行非破坏检验。结果表明:(1三种非破坏检验方法都能单独对七组样品进行不同程度的鉴别,区分率在50%—94.4%之间;(2)三种方法联用后对黑墨水、蓝黑墨水、蓝墨水、黑色墨水笔、蓝色墨水笔、黑色圆珠笔和蓝色圆珠笔的区分率可分别提高到93.4%、97.3%、99.1%97.2%、97.2%、95.6%和91.8%。通过三种非破坏检验方法的联用,证明它们之间有较强的互补性,最大限度地提高了检验效应,可建立系统的非破坏检验方法。     

Identification and dating of the fountain pen ink entries on documents by ion-pairing high-performance liquid chromatography

A novel approach for the identification and dating of the fountain pen ink entries on paper has been established by ion-pairing high-performance liquid chromatography (IP-HPLC). Twelve black and six red fountain inks have been collected, and their ink entries have been prepared by drawing lines on paper. The chromatographic conditions for separation of their dye components after extraction with solvents were optimized. Under the optimized conditions, the 18 fountain pen inks were differentiated individually by comparing the number of detectable main or minor dye components, and the relative peak intensities of each component. The ink entries were artificially and naturally aged, and the analysis results showed that the ink dye components were significantly decomposed when exposed to UV or fluorescent light compare to those of inks stored under natural condition. The changes of the relative peak height for the dye components were linearly related to the aging time, especially under natural aging conditions. The degradation characteristics of the dye components under different aging conditions provide scientific evidences for dating of the suspicious fountain pen ink entries on document.     

Raman spectroscopy of blue gel pen inks

Raman spectroscopy is becoming a tool of major importance in forensic science. It is a non-invasive, non-destructive analytical method allowing samples to be examined without any preparation. This paper demonstrates the use of the technique as a general tool for gel pen inks analysis. For this purpose, 55 blue gel pen inks, of different brands and models representative of gel pen available on the world market at the time of this study, were collected. A preliminary solubility test in methanol allowed separating them into two classes: 19 dye-based and 36 pigment-based gel inks. The latter were analysed by Raman spectroscopy (RS) using two wavelength laser sources (514.5 and 830 nm). Two main pigments were identified, pigment blue 15 and pigment violet 23.     

Experimental Research on Class Identification with a New Type of Erasable Gel Pens

A new type of erasable gel pen ink is becoming increasingly popular because of the modifiable characteristics for writing on documents. This study attempts to distinguish 12 types of blue and black erasable gel pens produced by mainstream stationery manufacturers using infrared (IR) visual analysis, Fourier transform infrared (FTIR) analysis, fluorescence analysis, and microspectrophotometry. The results demonstrate that IR visual, FTIR, and fluorescence analysis can be used to help distinguish each type of erasable gel ink. While microspectrophotometry can be used to effectively differentiate the blue gel inks in this study, there are limitations with respect to distinguishing black erasable gel pens. When these four optical analyses methods were used in combination, the gel inks could be accurately distinguished.     

Effect of electron beam irradiation on forensic evidence. 2. Analysis of writing inks on porous surfaces

The effect of electron beam irradiation on a series of different writing inks is described. As the anthrax-tainted letters were discovered in October 2001, the U.S. government began to experiment with the use of the electron beam irradiation process for destroying such biological agents. Plans initially considered a large-scale countrywide use of this technology. However, over time the scope of this plan as well as the radiation dosage were reduced, especially when some adverse consequences to mailed items subjected to this process were observed. Little data existed at the time to characterize what level of damage might be expected to occur with common items sent through the mail. This was especially important to museums and other institutions that routinely ship valuable and historic items through the mail. Although the Smithsonian Institution initiated some studies of the effect of electron beam irradiation on archived materials, little data existed on the effect that this process would have on forensic evidence. Approximately 97 different black, blue, red, green, and yellow writing inks were selected. Writing ink types included ballpoint, gel, plastic/felt tip, and rollerball. All noncontrol samples were subjected to standard mail irradiation conditions used by the U.S. Postal Service at the time this experiment was performed. A video spectral comparator and thin-layer chromatography (TLC) analysis were used to evaluate both the control and the irradiated samples. Some published studies reported changes in the presence/absence of dye bands in the chromatograms of irradiated writing inks. Some of these studies report the formation of additional dye bands on the chromatogram while others report missing dye bands. However, using standard testing guidelines and procedures, none of the 97 irradiated inks tested were found to show any significant optical or chemical differences from the control samples. In addition, random testing of some of the ink samples using a second solvent system did not reveal any changes. However, one control ink did show some minor changes in optical properties and dye characteristics over time (but not TLC) while the irradiated sample remained stable. Significant changes in the ultraviolet fluorescence characteristics of the irradiated paper samples themselves (not inks) were also observed.