Research On Optimizing The Method Of Indanedione To Develop Latent Fingerprints

Fingerprints,as one of the best forms of evidence for individual identification,appear frequently at the scene of cases.Therefore,developing latent fingerprints is of great significance to the investigation work.There are many ways to develop latent fingerprints,among which indanedione is widely used to develop sweat latent fingerprints due to its high sensitivity and suitability for a variety of permeable objects.However,the indanedione method is difficult to popularize due to the limitations of high operating conditions,unstable development effect,and insufficient equipment configuration.As a result,the application of indanedione in the domestic grass-roots actual combat is limited and the popularization is difficult.Therefore,it is necessary to establish a method for developing latent fingerprints of indanedione with better effect,higher safety and more convenient use.First of all,this paper analyzes the research results at home and abroad and improves the formula of indanedione working fluid on the existing basis to solve the problem that it is difficult to achieve high-temperature conditions above 100 ℃ in the survey site.By adding the humectants glycerol and propylene glycol from skin care products into the working solution and regulating their content,the appearance rate of the sweat latent fingerprints lines on the copy paper is increased from 71% to 93%.A better development effect without high temperature treatment is achieved,the operation process is simplified,and the work efficiency is improved.On this basis,a control experiment was designed to optimize the preparation process of the indanedione working solution by adjusting the components and proportions of acidifying reagents,polar solvents,carrier solvents,and zincating reagents.The methanol content in the working solution was reduced by 78%,from 45 m L to 10 m L.It not only improves the safety of reagents and protects operators,but also reduces background fluorescence interference and further enhances the development effect.Experiments were carried out with the working fluid prepared with the optimized formula to explore the relationship between environmental humidity,operation method,object of bearing marks and development effect.Finally,the optimization method of indanedione to develop the latent fingerprints was established to a provide reference for follow-up research.Finally,based on practical needs,this paper applies the optimization method to various types of latent fingerprints.The validity period,stability and sensitivity of the optimized formulation were tested,and the feasibility of combining multiple methods was explored.It is confirmed that the indanedione development method has a wide range of applications and high application value.The research also proves that the optimization method not only shows the latent fingerprints well,but also has less impact on the follow-up inspection.It provides a new idea for the application of indanedione in physical evidence identification.In this paper,a large number of samples were collected to carry out the above experiments,aiming to give full play to the evidence value of latent fingerprints,improve the work efficiency of front-line technicians,and establish an optimization method for indanedione to develop latent fingerprints with superior performance.This method can not only improve the sensitivity of reagents and enhance the development effect of fingerprints,but also has high safety,strong operability,wide application range,and little impact on subsequent tests.It provides a new strategy for the application and the promotion of indanedione development methods.