Determination of Trace Elemental Concentrations in Document Papers for Forensic Comparison Using Inductively Coupled Plasma–Mass Spectrometry

Abstract:  With improvements in manufacturing procedures, comparing physical characteristics of paper samples may not offer sufficient discrimination among different vendors. In this work, the potential to differentiate paper samples based on trace element concentrations was investigated. Paper samples from two different vendors were microwave-digested and trace element concentrations (Mg, Al, Mn, Fe, Sr, Y, Ba, Ce, and Nd) were determined using inductively coupled plasma–mass spectrometry. Differences in concentration were assessed statistically using two-way ANOVA and Tukey's honestly significant differences test. Elemental concentrations were shown to be consistent across a single sheet as well as within a single ream of paper for each vendor. Reams from vendor A were differentiated based on Al and Ba concentration while reams from vendor B were differentiated based on Mg, Mn, and Sr concentrations. Paper was differentiated according to vendor based on significant differences in Ba, Sr, Ce, and Nd concentrations.     

汶川地震相关的若干刑事问题研究

"5.12"汶川地震发生后,出现了很多疑难刑事法律问题,如建筑物毁损责任追究问题、趁灾造谣、非法经营、灾民哄抢救灾物资等行为的定性问题等,对于这些问题,应当区分不同情形,作出相应处理。     

利用暗记特征鉴别彩色激光打印、复印文件

目的探讨激光打印机的暗记特征,为鉴别彩色激光打印、复印文件找到一种有效的方法。方法根据不同物质对光的反射特性及蓝色与黄色互补特性的原理,采用420nm左右蓝光照射方法,对部分品牌彩色激光打印、复印文件进行了初步分析研究,总结了暗记点阵形态特征、小点形态特征、出现位置特征和排列含义等特征。结果此方法对彩色激光打印、复印机具的种类鉴别和个体鉴别简便、有效。     

同性恋违法行为及其成因分析

同性恋是一种社会现象,同性恋群体是社会群体中的特殊群体。近年来,同性恋违法行为日益突出,对社会管理造成了一定的影响。产生同性恋违法行为的原因主要在于：对同性恋的违法行为,法律界定不明确;社会对同性恋者存在歧视和偏见;同性恋者心理脆弱,缺乏安全感。     

红外线合成图像在变造文件检验中的应用与分析

在文件检验中,黑白红外线照相是一种检验变造文件的方法,然而,在某些情况下效果欠佳。为了提高检验的准确性,不妨可以应用红外线合成图像的方法。应用Photoshop图像处理方法,根据红外线彩色照相的感光原理和色彩再现过程,对数码照相机拍摄的可见光图像和红外线图像进行适当处理,即可生成红外线合成图像。这种图像可以反映字迹对可见光和红外线的吸收与反射情况,通过判断字迹颜色有否改变来检验书写色料的异同。由此可见,利用红外线合成图像方法检验某些变造文件,可以获得黑白红外线照相无法得到的检验结果,这对提高鉴定结论的准确性具有实际应用价值。     

合同诈骗抑或合同欺诈？

合同诈骗与合同欺诈是两类既相似又不相同的合同行为。司法实践中对包含有欺骗事实的合同行为的性质认定一直是个难点,这两者往往容易被混淆,导致许多判决结果存在争议,所以,应对两者之间的区别进行全面把握,以利于司法实践。     

运输毒品罪的法律辨析

运输毒品的行为往往是其他毒品犯罪的辅助行为,运输毒品罪往往与其他毒品犯罪交叉和竞合。为了更准确地定罪,必须认识到运输行为的本质是：在国（边）境内,转移明知的毒品的地理位置。对于该罪的既未遂形态,应当根据运输方式的不同分别认定;与转移毒品罪和非法持有毒品罪的区别必须依赖于行为人的主观方面;运输毒品罪与走私毒品罪的根本区别在于移动毒品的地理位置的不同。     

Age determination of ballpoint pen ink by thermal desorption and gas chromatography-mass spectrometry

Two main approaches can be used for determining the age of an ink: indirect dating and direct dating. Indirect dating is based on the chemical analysis of an ink followed by comparison with known samples in a reference collection. The collection should contain information about the inks including the market introduction dates. This approach may allow for an anachronism to be detected. The second concept is based on measuring ink components that change with age. The analysis of solvents in ballpoint inks may be a useful parameter for determining the age of ink on paper. In a previous study, the authors demonstrated that thermal desorption of ink directly from paper, followed by chemical analysis using gas chromatography-mass spectrometry (GC-MS), is a promising procedure for characterizing ink-binder resins and solvents. Preliminary tests showed that monitoring the evaporation of ink solvent from ink on paper is not a suitable method for ink dating. Thermal analysis of ink on paper in two steps revealed that fresh ink releases a relative amount of solvent at a certain low temperature in a defined period of time, which decreases as the ink ages. As a consequence, this relative amount of solvent released at a certain low temperature, and its decrease with time, can be used to estimate ink age. This age-dependent parameter was studied in 85 different inks ranging in age from 1 week to 1.5 years. It was found that some inks showed a significant decrease of this parameter up to an age of several months, and that the aging process can be monitored within this period. For other inks, however, the age-dependent parameter decreases relatively fast, e.g., within a few days, to a constant level, which can be too fast for casework. Based on these results, a general procedure for assessing the age of ballpoint pen inks on paper was developed.     

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.     

试析巨额财产来源不明罪

巨额财产来源不明罪自其创设起就是一个颇有争议的罪名 ,通过分析该罪的构成要件 ,认为“司法机关无法查清巨额财产的真实来源”不是本罪客观要件的内容。分析了本罪在现实中出现的尴尬境况 ,认为前置制度的缺乏是导致其尴尬境况的深层次原因 ,并对本罪的完善提出了建议