Development and validation of an FT-IR method for quantitative assessment of immature fiber content in cotton samples

Within-sample variation in cotton fiber maturity is crucial in the textile industry for predicting and maintaining the quality of end-use products. Accurate and efficient assessments of maturity variation within and among cotton materials are required to improve the quality of yarns and fabrics. Maturity variation is monitored in terms of immature fiber content (IFC) by a reference microscopy method requiring slow processes and extra cost of analyzing individual fiber properties. Attenuated total reflection (ATR) Fourier-transform infrared (FT-IR) spectroscopy has been proposed as a rapid alternative for monitoring cotton fiber maturity, based on its capacity to differentiate chemical characteristics between mature and immature fibers. Conventional FT-IR method analyzing the spectra by multivariate data analyses lacked the ability to provide quantitative IFC values. Thus, a novel FT-IR algorithm was developed to overcome the limitation of conventional FT-IR methods. This algorithm utilizes spectral regions responsive to the chemical components in immature fibers and formulates a metric denoted as the infrared immaturity ratio (IIR). The efficacy of the IIR algorithm was demonstrated by comparing its performance with the reference microscopy method. It allowed for the quantitative differentiation of a broad range of IFC values (1.50–45.17%) tested from the reference and experimental cotton materials. The newly developed algorithm offers a quantitative, rapid, and noninvasive approach to monitoring maturity variation within and among cotton samples.