Authors: Xinyi Sui
Source: NCSU Libraries Repository (North Carolina State University Libraries) (article, 2020-11-10)
Field: Chemistry — Analytical Chemistry

Qualitative and Quantitative Bio-degradation Study of Dyes and Textile Auxiliaries in Soil. SUI, XINYI.Qualitative and Quantitative Bio-degradation Study of Dyes and Textile Auxiliaries in Soil.(Under the direction of Dr. Nelson Vinueza).Society has been constantly seeking and making cotton fabrics with better quality and functionality.This includes the alteration of color by using natural or synthetic dyes and the enhancement of commercial and aesthetic properties by applying chemical finishes.One excellent example illustrating this kind of innovation is the discovery of reactive dyes by Imperial Chemical Industries in the 1950s.Reactive dyes use a chemical reaction to create a new covalent bond between the cellulose chain and chromogen, giving the cotton fabric better colorfastness against washing and abrasion.Besides coloration by synthetic dyes, another approach to obtain cotton fabrics with enhanced properties and performance is to apply different chemical finishes onto them like anti-wrinkle and anti-microbial agents.The combination of reactive dye application and chemical finishing has resulted in considerable growth in the use of cotton fabrics.Nowadays, landfilling is the common disposal route for textile fabrics (natural or synthetic), generating an important source of potential contamination due to the migration of dyes and finishes onto soil during the decomposition of these chemicals by microorganisms.The biodegradation of cotton fabrics containing dyes and finishings in a compost is not fully understood.Furthermore, what happens to these chemicals under this decomposition environment is still unknown.In this project, the chemical changes that happen to cotton fabrics containing reactive dyes or chemical finishes during a small-scale compost process under ASTM D 5988-18 are studied.Analytical methods that include extraction, liquid chromatography, High-Resolution Quadrupole Time-Of-Flight Mass Spectrometry, and tandem mass spectrometry are used in this fundamental study.First, via a joint forces of modified QuEChERS extraction method and QTOF mass spectrometry, four degradation products were identified based on exact mass measurement after a simulated composting process on cotton fabrics dyed with four commonly used reactive dyes including RO35, RB49, Rblk 5, and RB19.Then a quantification method aiming to measure the concentration of docusate antimicrobial in soil after the simulated composting process was developed through a combination of QuEChERS extraction, quantitative tandem mass spectrometry, and isotopically labeled internal standard.After establishment, this method was validated according to FDA guidelines, and results suggested that this method have good linearity (R 2 > 0.99), good accuracy (mean % error less than 15%), good precision (mean % CV less than 15%), good sensitivity (measured docusate concentration is 400% higher than LOD and 100% higher than LLOQ), satisfying matrix effect, and the concentration of docusate (515 ng/mL) falls within the linear range of calibration.Finally, two degradation products from the aqueous degradation of RB19-dyed cotton fabric were extracted by QuEChERS extraction and identified based on QTOF mass spectrometry and qualitative tandem mass spectrometry against the standard. Textile ; Degradation (telecommunications) ; Qualitative analysis ; Pulp and paper industry ; Waste management ; Environmental science ; Engineering ; Qualitative research ; Archaeology ; Geography ; Sociology ; Social science Analytical chemistry methods development ; Pesticide and Herbicide Environmental Studies ; Dye analysis and toxicity