DEVELOPMENT AND USE OF AN ATR/FT-IR SPECTRAL DATAABASE TO IDENTIFY FOREIGH MATTER IN COTTON

Authors: Himmelsbach, David; HELLGETH, JOHN - HEWLETT PACKARD; McAlister Iii, David

Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Proceedings
Publication Acceptance Date: 11/2/2005
Publication Date: 1/6/2006
Citation: Himmelsbach, D.S., Hellgeth, J.W., Mcalister III, D.D. 2006. Development and use of an atr/ft-ir spectral dataabase to identify foreigh matter in cotton. Beltwide Cotton Conferences, National Cotton Council. pp. 2386-2397.

Interpretive Summary: The contamination of cotton with foreign matter reduces the value of cotton in the market place. This “trash” travels with the cotton lint as it is processed and often makes it way into the final product. As cotton goes though the various stages of cleaning and processing these trash particles get smaller and/or redistributed making it difficult to impossible to identify them from their physical appearance. Thus, other means of determining the source of the contamination are required. Most of the foreign matter associated with cotton is organic in nature. Infrared spectroscopy is well suited for this type if analysis. This work has shown that infrared analysis involving pressing a small piece of matter in question onto a diamond crystal and passing infrared light though the crystal can yield a suitable spectrum of these types of material. By comparison of the spectrum of the contaminant to spectra of authentic samples identification of the foreign matter can be made. This information can then used to discover the source of the foreign matter and lead to methods of prevention, remediation or control of the foreign matter that is retained in the final product.

Technical Abstract: The presence of foreign matter in cotton seriously affects the cotton grade and thus the price per bale paid by the spinner, the efficiency of the spinning and ginning operations and the quality of the final woven product. Rapid identification of the nature of the extraneous matter in cotton at each stage of cleaning and processing is necessary permit actions to eliminate or reduce its presence and improve efficiency and the quality. Although several instruments are being successfully employed for the measurement of contamination in cotton fibers based on particle size/weight, no commercial instrument is capable of accurate qualitative identification of contaminants. To this end, ATR/FT-IR spectra of retrieved foreign matter were collected and subsequently rapidly matched to an authentic spectrum in a spectral database. The database includes contaminants typically classified as “trash”: cotton plant parts (hull, shale, seed-coat fragments, bract, cacyx, leaf, bark, sticks and stems) and grass plant parts (leaf and stem), “foreign objects and materials”: synthetic materials (plastic bags, film, rubber, bale wrapping and strapping), organic materials (other fibers, yarns, paper, and leather) plus entomological and physiological sugars and inorganic materials (sand and rust). The spectral matching resulted in consistently high-score identification of the foreign matter based on chemical composition, irrespective of its particle size. The method is envisioned to be employed with stand-alone rugged infrared instrumentation to provide specific identification of extraneous materials in cotton as opposed to only general classification of the type by particle size or shape.