The Importance of Thin Layer Chromatography in the Analysis of Reactive Dyes Released from Wool Fibers

Abstract

Samples of reactively-dyed wool were obtained from a range of manufacturers and distributors and “digested” by alkaline hydrolysis to yield colored solutions. Results demonstrate that thin layer chromatographic analysis of reactive dyes yields important additional information, over and above that obtained from techniques such as comparison microscopy and visible light microspectrophotometry. Colored solutions obtained from single fibers were analyzed by thin layer chromatography (TLC) and reproducible results were obtained from a range of fiber lengths.

Forensic comparison of synthetic fibers

“…[63] The use of UV-vis together with thin-layer chromatography (TLC) is a long-standing practice and is well studied and reported in the literature. [64][65][66] UV-vis is a technique complementary to TLC. In some cases, UV-vis distinguishes pairs of fibers that are not discriminated by TLC.…”

“…However, numerous solvent mixture systems have been documented for this purpose. [60] Studies of dye extraction and TLC have been published for dyes on cotton, [69,70] wool, [71][72][73][74] and various other synthetic fibers. [69,75,76] TLC is able to identify the extracted dyes and dye mixtures, but most of the textile fibers contain complex dye patterns.…”

Extraction and Analysis of Disperse Dyes from Colored Polyester Single Fibers Using Liquid Chromatography/Linear Ion Trap Tandem Mass Spectrometry

“…1,2 Many studies have been conducted to analyze the dyes in colored fibers using microspectrophotometry, [3][4][5][6][7][8][9][10] TLC, [11][12][13][14][15][16][17][18][19] HPLC, [20][21][22][23][24][25] and LC/MS, [26][27][28][29][30] because these dyes can provide significant information in forensic analyses.…”

“…31 Dye-extractions are performed by heating colored fibers in various solvents and solvent mixtures, [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] including the recommended pyridine/water (4:3, v/v) mixture by the SWGMAT guidelines. 32 We reported a method for extracting a residual surfactant from threads using centrifugal filtration of a methanol solution extracted into a glass capillary.…”

Analysis of Disperse Dyes Using Liquid Chromatography/Linear Ion Trap Mass Spectrometry (LC/LIT-MSn) and Database Construction

“…Standard dye database constructed based on these methods would make it possible to provide useful information for a criminal investigation by the identification of subtypes of dyes collected at the crime scenes without reference fibers to compare with. Analytical techniques for the dyes in single fibers can be classified into spectroscopic methods, including microspectroscopy; Raman spectroscopy and MSP; [3][4][5][6][7][8][9][10][11][12][13][14][15] and chromatographic methods, such as thin-layer chromatography (TLC), [16][17][18][19][20][21][22][23][24] high-performance liquid chromatography (HPLC), [25][26][27][28][29] and liquid chromatography mass spectrometry (LC/MS). [30][31][32][33][34] As described below, the above methods are known to have some drawbacks.…”