Discrimination Between Infant and Adult Bloodstains Using Micro-Raman Spectroscopy: A Preliminary Study

In the present study, we used micro-Raman spectroscopy with high-resolution analysis to discriminate between bloodstains from infants and bloodstains from adults. Raman peaks were detected at 674, 754, 976, 1002, 1105, 1127, 1176, 1248, 1340, 1368, 1390, 1560, and 1611 cm^-1 ; these peaks were derived from hemoglobin, albumin, and glucose. However, a peak was obtained at 1105 cm^-1 , which was assigned to histidine; this peak was observed only for bloodstains from adults. Human adult hemoglobin (HbA) is composed of an α₂ β₂ tetramer structure, whereas human fetal hemoglobin (HbF) is composed of an α₂ γ₂ . Therefore, the lack of a Raman peak at 1105 cm^-1 in bloodstains from infants indicates the possibility of two histidine substitutions (His116Ile and His143Ser) in the γ chain of HbF. This study discriminates between bloodstains from infants and bloodstains from adults using micro-Raman spectroscopy, with beneficial implications in forensic science.