Enhanced imaging of developed fingerprints and its contaminated substance using ToF-SIMS

[Display omitted] •Enhancing fingerprints on surfaces poorly visualised by conventional methods.•Demonstrating improved fingerprint imaging effects on challenging textiles systematically.•Analyzing morphological changes of fingerprints within 3 months.•Investigating the unstable fingerprint pore characteristics on porous objects.•Detecting exogenous contamination of developed fingerprint by TOF-SIMS. Fingerprint is a common form of evidence utilized in crime cases, providing crucial information for suspect identification and the proof of key facts. However, traditional development methods are often ineffective for challenging fingerprints due to variations in information and surface characteristics, potentially causing damage to the fingerprint substance. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) offers a non-destructive approach that combines spatial imaging with mass spectrometry capabilities. This study employed ToF-SIMS to enhance natural fingerprints that showed poor visualization when treated with 1,2-indandione and ninhydrin on porous surfaces such as printing paper, kraft paper, newspaper, and thermal paper, especially on challenging textiles. We also imaged fingerprints on nonporous surfaces that were deposited over 30 days ago using ToF-SIMS, like aluminum foil, express packaging bags, and slides. We then extended the age of fingerprint detection to 3 months to explore the relationship between the aging of fingerprints and the morphological characteristics of sweat pores. Furthermore, the study examined the detection capabilities of ToF-SIMS on fingerprints contaminated with compound econazole nitrate cream after being interfered with by development agents, illustrating its effectiveness in extracting comprehensive fingerprint information.