This article describes an exploration of the use of surface-enhanced Raman spectroscopy for the detection and identification of black and blue dyes hair dyes, on hair submerged in hypolimnion water for up to twelve weeks, providing insights relevant to forensic scientists and other practitioners for the determination of a victim’s identity.
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, the authors 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. The authors found that SERS enabled 100 percent accurate identification of analyzed dyes on hair submerged in hypolimnion water for up to eight weeks, whereas, on average, 87 percent accurate identification of the hair dyes could be achieved on hair exposed for 10 weeks and 50 percent for hair exposed 12 weeks in hypolimnion water. The authors also found that the aqueous environment caused progressive fading of some dyes, whereas other dyes showed substantial spectral transformations after prolonged submergence. Finally, they 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. Publisher Abstract Provided