The relationship between instrumental leaf grade and Shirley Analyzer trash content in cotton lint

Authors: Liu, Yongliang; Delhom, Christopher - Chris

Submitted to: Textile Research Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/3/2017
Publication Date: 3/10/2017
Citation: Liu, Y., Delhom, C.D. 2017. The relationship between instrumental leaf grade and Shirley Analyzer trash content in cotton lint. Textile Research Journal. 88(10):1091-1098. https://doi.org/10.1177/0040517517697641.
DOI: https://doi.org/10.1177/0040517517697641

Interpretive Summary: Commercial cottons contain some degree of non-lint related contaminant (or trash) that compromises cotton market value and requires further cleaning steps. With the increasing acceptance of HVITM instrumental leaf grade index in both domestic and international trading, there is a continued interest in the relationship between instrumental leaf grade and equivalent trash content in gravimetric percentage from cotton customers and regulators. Due to the complexity of not only trash type, size, and its weight distribution but also the nature of HVITM and gravimetric methods, it is an on-going challenge to unravel such a relationship. This study examined the relationships between three Shirley Analyzer trash readings (SAvisible, SAinvisible, and SAtotal) and respective leaf grade categories, and also compared the SAvisible trash content in current study to that in earlier studies. The outcome provides cotton fiber / textile engineers and regulators a new sight in understanding the relationship among different cotton trash measurements.

Technical Abstract: With the increasing acceptance of high volume instrument (HVITM) instrumental leaf grade index in both domestic and international trading, there is a continued interest in the relationship between instrumental leaf grade and equivalent trash gravimetric content (% percent by mass) from cotton customers and regulators. Due to the complexity of not only trash type, size, and its weight distribution but also the nature of HVITM and gravimetric methods, it is an on-going challenge to examine such a relationship. In this study, the Shirley Analyzer (SA) was used to determine the gravimetric cotton trash in percent by mass (%). This system is the traditional cotton trash reference method which is still utilized as a routine tool in cotton industry, despite being a destructive process that is both labor-intensive and time-consuming. This study first investigated the correlations between three SA trash readings (SAvisible, SAinvisible, and SAtotal) and respective leaf grade categories, and it revealed a general trend of increasing SAvisible and SAtotal trash content with elevating leaf grade. Then, comparison of SAvisible trash content in current study to that in separate studies indicated a good agreement for low leaf grade cottons (< 4). Next, principal component analysis (PCA) of near infrared (NIR) spectra from SAvisible trash portions revealed a different pattern in PC1 score between low leaf grade (1 to 4) and high leaf grade (5 and 6) SAvisible remains, implying a general transition of chemical and compositional components in trash from low to high leaf grade cottons.