Thonglon Thatsanee, Chaikum Nopadol
Faculty of Science, Forensic Science Graduate Programme, Mahidol University, Bangkok, Thailand.
J Forensic Sci. 2010 Sep;55(5):1343-6. doi: 10.1111/j.1556-4029.2010.01432.x.
A study was conducted to investigate whether natural magnetite (Fe3O4), which is an abundant mineral in Thailand, could be used as a magnetic powder in the detection of latent fingerprints. Because of the presence of impurities, powdered magnetite is only weakly attracted by a magnet and cannot be used as a magnetic fingerprint powder by itself. Mixing a small amount of magnetite powder with nickel powder greatly enhances the magnetic attraction. A mixture of magnetite powder and nickel powder in a mass ratio of approximately 1:100 was found to be suitable for use as a magnetic fingerprint powder. Fingerprints developed using the magnetite/nickel mixture on nonporous surfaces were found to exhibit good adherence and clarity. Using an automated fingerprint identification system, the number of minutiae detected in fingerprints developed by using the prepared powder on nonporous surfaces was found to be comparable to those detected in fingerprints developed by using a commercial black magnetic powder. The cost is lowered by more than 60%.
开展了一项研究，以调查泰国储量丰富的天然磁铁矿（Fe3O4）是否可用作检测潜在指纹的磁性粉末。由于存在杂质，粉末状磁铁矿仅被磁铁微弱吸引，不能单独用作磁性指纹粉。将少量磁铁矿粉与镍粉混合可大大增强磁吸引力。发现磁铁矿粉与镍粉质量比约为1:100的混合物适合用作磁性指纹粉。在无孔表面上使用磁铁矿/镍混合物显影的指纹具有良好的附着力和清晰度。使用自动指纹识别系统，发现在无孔表面上使用制备的粉末显影的指纹中检测到的细节特征数量与使用商业黑色磁性粉末显影的指纹中检测到的相当。成本降低了60%以上。
