Quantification of cotton content in textiles by near-infrared spectroscopy

Significance of the topic

The accurate determination of cotton content in textile blends is essential for quality control, regulatory compliance and sustainable material use. Traditional methods for fiber composition analysis are laborious, time-consuming and often destructive. Near-infrared spectroscopy (NIRS) offers a rapid, non-destructive, reagent-free alternative capable of delivering reliable results in seconds, benefiting manufacturers, laboratories and end-users alike.

Objectives and study overview

This study aimed to develop and validate a quantitative NIRS method to determine the percentage of cotton in cotton/polyester textile blends. A calibration model was built using a representative set of samples, and its predictive performance was assessed through cross-validation.

Methodology and Instrumentation used

A total of ten textile samples with varying cotton and polyester ratios were analyzed. Spectral data were acquired in the visible-near-infrared range (400–2500 nm) using a DS2500 Solid Analyzer equipped with a large sample cup and matching lid to ensure consistent sample positioning. Data acquisition and chemometric model development were performed with Vision Air 2.0 Complete software.

• DS2500 Solid Analyzer
• DS2500 large sample cup
• DS2500 lid for large sample cup
• Vision Air 2.0 Complete software

Results and Discussion

Vis-NIR spectra of the ten samples were used to build a partial least squares regression model correlating spectral features to reference cotton percentages. Key performance metrics:

• Coefficient of determination (R²): 0.9975
• Standard error of calibration: 1.2 % cotton
• Standard error of cross-validation: 1.4 % cotton

The high R² and low errors demonstrate excellent predictive accuracy and precision. Spectral regions assigned to O–H and C–H overtone bands provided the main contrast between natural and synthetic fibers. The method’s rapid measurement (under 30 s) and non-destructive nature make it suitable for routine quality control.

Practical benefits and applications

The NIRS approach offers multiple advantages:

• Speed: results in less than 30 seconds per sample
• Non-destructive testing: textiles remain intact for further use or analysis
• Chemical-free operation: no reagents or sample pre-treatment required
• Cost efficiency: reduced labor and material consumption

These features support rapid throughput in production environments, on-site quality assurance and compliance with labeling standards.

Future Trends and Applications

Advancements likely to enhance textile NIRS include:

• Integration of portable and handheld NIRS instruments for in-field testing
• Implementation of machine learning algorithms for improved calibration robustness
• Expansion to other fiber types and complex multi-material blends
• Coupling with hyperspectral imaging for spatially resolved composition mapping
• Real-time monitoring of production lines to enable inline quality control

Conclusion

This application demonstrates that NIRS using the DS2500 platform provides a fast, accurate and non-destructive solution for quantifying cotton content in textiles. The high correlation between predicted and reference values confirms its suitability for routine analysis, offering significant improvements over traditional methods in speed, cost and sustainability.

Reference

AN-NIR-118: Quantification of cotton content in textiles by near-infrared spectroscopy