Nondestructive Total Excitation–Emission Fluorescence Microscopy Combined with Multi-Way Chemometric Analysis for Visually Indistinguishable Single Fiber Discrimination

Abstract

The potential of total excitation-emission fluorescence microscopy combined with multiway chemometric analysis was investigated for the nondestructive 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 full information content of excitation-emission matrices was processed with the aid of 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 nondestructive analysis of forensic fiber evidence.

Modeling second-order data for classification issues: Data characteristics, algorithms, processing procedures and applications

“…processes, storage, harvest or variety). Other relevant works have been orientated to more specific research, such as the forensic analysis of textile fibers [40,41], the characterization of organic constituents of soils [42], discrimination of geographical origin and detection of adulteration of burdook and kudzu roots [43,44], and for the identification of biodiesel and petroleum oils with environmental purposes [7,45,46]. Several recent reviews have been published about this ever increasing research field where relevant applications can be found [47][48][49][50][51][52][53].…”

“…Accordingly, the simplest implemented strategies, when the affected areas do not contain relevant information, are reducing the areas of analysis, previously to the measurements, selecting the wavelength range from which the scattering effects are not produced [40,41]. However, important information about some sample fluorophores can be lost [41].…”

“…An interesting application of PARAFAC followed of LDA was presented by Muñoz de la Peña and co-workers [40]…”

“…LDA CV scores (3 components PARAFAC model) for 40 samples of the dyes AY17 and AY23 on nylon-361 fibers. The three dimensional projection of the 95%M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPTconfidence ellipse of the data collected from each type of fiber is included to facilitate visualization of the obtained results[40].…”

Excitation–emission matrix fluorescence spectroscopy combined with MCR-ALS as a tool for the forensic analysis of similar and dissimilar sets of textile fiber extracts

“…Recently, single ber identication with nondestructive excitation-emission uorescence spectroscopy combined with different chemometric techniques has been reported by our group. [9][10][11] This subject is of current interest, as is reported in a recent review on forensic comparison of synthetic bers. 12 Our approach takes room temperature uorescence (RTF) spectroscopy to a higher level of selectivity.…”