Near Infrared Measurement of Cotton Fiber Micronaire by Portable Near Infrared Instrumentation

In the U. S. A., cotton is classed (primary quality parameters) by the Uster (R) High Volume Instrument (HVI), which must be maintained under tightly controlled laboratory environmental conditions. Improved and fast response quality measurement systems and tools are needed to rapidly assess the quality of cotton. One key area of emphasis and need is the development and implementation of new fast-response quality measurements that can be used not only in the laboratory but which also can be adapted to field and at-line quality measurements. A program was implemented to determine the ability of portable near-infrared (NIR) instrumentation to monitor critical fiber properties of cotton samples in the laboratory, at-line, and in the field, with initial emphasis on the laboratory measurement of cotton fiber micronaire. Micronaire is a key cotton property, and it is an indicator of the fiber's maturity and fineness. Distinct NIR spectral differences between samples with varying micronaire were observed. A comparative evaluation was performed to determine optimum instrumental conditions for laboratory cotton micronaire measurements. The comparative evaluation established that the optimum instrumental conditions for laboratory measurements of micronaire was obtained with the use of a glass-covered sampling port and increased instrumental gain, with high R-2 values, low residuals, and with <= 12% outliers. For a NIR measurement with potential for multiple simultaneous analyses and non-laboratory measurements, the micronaire measurement was fast (< 3 min per sample) and easy to perform. The rapid and accurate laboratory measurement of cotton fiber micronaire with portable NIR instrumentation was demonstrated.