This study sought to identify a person’s age range using dried bloodstains.
Forensic chemistry is an important and rapidly growing branch of analytical chemistry. As a part of forensic practices, phenotype profiling is beneficial to help narrow down suspects. In the current study, attenuated total reflection Fourier transform-infrared (ATR FT-IR) spectroscopy was used to acquire information about the total (bio)chemical composition of a sample. This proof-of-concept study used a diverse pool of donors, including those in newborn (<1), adolescent (11–13), and adult (43–68) age ranges. Different donor age groups were found to have different levels of lipids, glucose, and proteins in whole blood, although the corresponding spectral differences were minor; therefore, the collected data set was analyzed using chemometrics to enhance discrepancy and assist in donors’ classification. A partial least squares discriminant analysis (PLSDA) was used to classify ATR FT-IR spectra of blood from newborn, adolescent, and adult donors. The method showed a 92 percent correct classification of spectra in leave-one-out cross-validation (LOOCV) of the model. Overall, ATR FT-IR spectroscopy is nondestructive and can be an in-field method that can be used for a variety of forensic applications. In general, the developed approach combining ATR FT-IR spectroscopy and advanced statistics shows the potential for classifying (bio)chemical samples that have significant intra-class variations. (publisher abstract modified)