Surface‐enhanced Raman spectroscopy enables confirmatory detection of dyes on hair submerged in hypolimnion water for up to twelve weeks

Abstract

Difficulties in the localization of bodies of homicidal or drowning victims in natural water result in their submergence for weeks if not months. Water insects and microbes drastically change the body's appearance, which significantly changes the determination of a victim's identity. DNA analysis is commonly used for identifying the decedent; however, this PCR‐based approach is time‐consuming and destructive of the evidence. Considering that nearly half of the people in the world dye their hair with a variety of permanent and semi‐permanent dyes, one can expect that confirmatory identification of dyes on the body's hair can be used to shed light on the victim's identity. A growing body of evidence suggests that surface‐enhanced Raman spectroscopy (SERS) can be used to detect and identify hair dyes. In this study, we investigated the extent to which SERS could be used to detect black and blue, permanent and semi‐permanent dyes on hair submerged in hypolimnion water for up to twelve weeks. We found that SERS enabled 100% accurate identification of analyzed dyes on hair submerged in hypolimnion water for up to 8 weeks, whereas, on average, 87% accurate identification of the hair dyes could be achieved on hair exposed for 10 weeks and 50% for hair exposed 12 weeks in hypolimnion water. We also found that the aqueous environment caused progressive fading of some dyes, whereas other dyes showed substantial spectral transformations after prolonged submergence. Finally, we found that changes in the intensity of vibrational bands of dyes could be used to predict the duration of submergence of colored hair in hypolimnion water.

Using surface-enhanced Raman spectroscopy to probe artificial dye degradation on hair buried in multiple soils for up to eight weeks

“…In the context of hair, Kurouski and Van Duyne demonstrated how using gold nanoparticles could lead to the strong resonance of colorants found in dyes on dyed hair 10 . Since then, SERS has been used to detect and differentiate over 30 different dyes on hair, as well as probe the degradative effects and still detect the colorant on hair subjected to high heat and weeks of sunlight and lake water exposure 11 – 14 .…”

Non-Destructive Identification of Dyes on Fabric Using Near-Infrared Raman Spectroscopy

“…RS has previously been used to identify urine, sweat, semen, blood, hair colorants, and gunshot residue [14][15][16][17][18][19]. It should be noted that RS is a non-destructive and non-invasive technique [20][21][22]. Therefore, it can be used to identify the origin of highly vulnerable historical fabrics that have dyes or pigments [9].…”