Title

Forensic Analysis of Anthraquinone, Azo, and Metal Complex Acid Dyes from Nylon Fibers by Micro-extraction and Capillary Electrophoresis

Department

Chemistry & Biochemistry

Document Type

Article

Publication Date

8-1-2009

Abstract

The extraction and separation of dyes present on textile fibers offers the possibility of enhanced discrimination between forensic trace fiber evidence. An automated liquid sample handling workstation was programmed to deliver varying solvent combinations to acid-dyed nylon samples, and the resulting extracts were analyzed by an ultraviolet/visible microplate reader to evaluate extraction efficiencies at different experimental conditions. Combinatorial experiments using three-component mixture designs varied three solvents (water, pyridine, and aqueous ammonia) and were employed at different extraction temperatures for various extraction durations. The extraction efficiency as a function of the three solvents (pyridine/ammonia/water) was modeled and used to define optimum conditions for the extraction of three subclasses of acid dyes (anthraquinone, azo, and metal complex) from nylon fibers. The capillary electrophoresis analysis of acid dye extracts is demonstrated using an electrolyte solution of 15 mM ammonium acetate in acetonitrile/water (40:60, v/v) at pH 9.3. Excellent separations and discriminating diode array spectra are obtained even for dyes of similar color.

Journal

Analytical and Bioanalytical Chemistry

Journal ISSN

1618-2642

Volume

394

Issue

8

First Page

2077

Last Page

2085

Digital Object Identifier (DOI)

10.1007/s00216-009-2875-9