Forensic analysis of visually indistinguishable fibers using excitation-emission microscopy combined with multi-way chemometrics

NIRVANI MUJUMDAR, ; ARSENIO MUNOZ DE LA PENA; EMILY C. HEIDER,; HECTOR GOICOECHEA; DAVID MUNOZ DE LA PENA; ANDRES CAMPIGLIA

Congreso; American Chemical Society 67th SERMACS, 2015; 2015

The potential of the non-destructive total excitation-emission fluorescence microscopy combined with multi-way chemometric analysis was investigated for the forensic analysis of textile fibers. The four pairs of visually indistinguishable fibers consisted of nylon 361 dyed with acid yellow 17 and acid yellow 23, acetate satin 105B dyed with disperse blue 3 and disperse blue 14, polyester 777 dyed with disperse red 1 and disperse red 19, and acrylic 864 dyed with basic green 1 and basic green 4. Excitation emission matrices were recorded with the aid of an inverted microscope and a commercial spectrofluorimeter. The information content of excitation-emission matrices was processed with the aid of principal component analysis (PCA), unsupervised parallel factor analysis (PARAFAC), PARAFAC supervised by linear discriminant analysis (LDA), and discriminant unfolded partial least squares (DU-PLS). The ability of the latter algorithm to classify the four pairs of fibers demonstrates the advantage of using the multidimensionality of fluorescence data formats for the non-destructive analysis of forensic fiber evidence.