水性印油印迹中时间性特征物质筛选及降解机理研究

Screening and degradation mechanism of dating substances in water-based stamp ink imprints

针对水性印油印迹,采用液质联用仪、气质谱联用仪等综合分析方法,明确了该类印迹中主要色料成分为酸性红R、水溶曙红Y、酸性橙Ⅱ、金光红、金光红C、罗丹明B、颜料红112等,主要溶剂成分为1,2-丙二醇、甘油、二甘醇、四甘醇、五甘醇、六甘醇等。结合人工老化和自然老化方法发现:溶剂成分中五甘醇、六甘醇可检出时间在6~12月;以罗丹明B和其系列副产物随时间变化明显,其降解机理为脱乙基为主。结合罗丹明B类物质和六甘醇类物质,可以作为该类印油盖印时间检验的物质指针,为相关专业检验者提供检验依据。

This paper focuses on the imprint of new water based stamp-pad ink,and by using liquid chromatography-mass spectrometry（LC/MS） and gas chromatography-mass spectrometry（GC/MS）.It is determined that the pigments in this kind of imprints mainly consist of acid red R,water soluble eosin Y,acid orange Ⅱ,golden light red,golden light C,rhodamine B,pigment red 112,and so on,while the main volatile matters are 1,2-propanediol,glycerol,diethylene glycol,tetraethylene glycol,pentaerythritol,hexaethylene glycol and the like. Furthermore,combined with artificial aging and natural aging methods, it should take 6 to months to detect the auxiliary ingredients such as pentaethylene glycol and hexaethyleneglycol,which can be used to determine whether the file is formed recently. The amount of rhodamine B in the pigments and its by-product,generated by the main mechanism of the degradation is the removal of ethyl,changes obviously with time,which can be used to determine whether the file is formed long time ago. Rhodamine B and alcohol ingredients were used as the target to determine the formation time of the imprint of water-based stamp-pad ink,which will provide guidance for those working for examining questioned documents.