| Natural colored cotton is the main material of healthy and environmental friendly textiles.As the natural colored cotton has more complicated planting process and lower yield,its price is much higher than the ordinary white cotton.Thus,fake natural colored cotton is often made through adulteration and counterfeiting.More and more enterprises and consumers pay attention to the authenticity identification technology and methods of natural colored cotton.In this study,natural colored cotton and dyed colored cotton were used as test subjects,the spectra of cotton samples were collected by Antaris?FT-NIR spectrometer,and NIRSA4.0 and MATLAB R2016 b were used as the data processing platforms to process the spectra.The methods of discriminating adulteration and fraud of natural colored cotton were studied.The two-dimensional correlation near-infrared spectroscopy technique with concentration disturbance(white cotton as external disturbance)was used to study the quality inspection method of natural colored cotton,providing a scientific basis for inspection and supervision for the import and export of natural colored cotton.The implementation of this research project has important practical significance to improve the international market competitiveness of China's natural colored cotton and its products,to break the barriers of foreign trade,and to enhance the export of China's cotton and textile products.The main achievements of the study are as follows:(1)To realize the rapid detection of natural colored cotton,natural colored cotton was taken as the test object,the near-infrared spectra of the samples were collected using the Antaris?FT-NIR spectrometer in the spectral range of 10 000~4 000 cm-1,and NIRSA 4.0 and MATLAB R2016 b software platforms were used for studying multiple pattern recognition methods.The results showed that unsupervised pattern recognition analysis could separate natural colored cotton and dyed colored cotton,and the supervised discrimination model established by the SIMCA method had best recognition effect to cotton samples.Therefore,near infrared pattern recognition analysis method can achieve the purpose of rapid identification of natural colored cotton.(2)To study the practical method for quality analysis of natural colored cotton by two-dimensional correlation near-infrared spectroscopy,four groups of cotton samples(i.e.pure natural colored cotton,natural colored cotton adulterated with 30% and 50% dyed colored cotton,and pure dyed colored cotton)were used as the test objects.Near-infrared spectroscopy and two-dimensional correlation analysis technology were integrated to realize further identification of the quality of natural color cotton.It was found that the one-dimensional near-infrared spectra of all the samples were similar.Therefore,it was difficult to recognize the doping samples based on these spectra.However,the use of two-dimensional near-infrared spectroscopy could effectively improve the resolution of the spectrum and improve the correctness of recognition,providing a more intuitive and accurate method for distinguishing the quality of natural colored cotton.(3)In order to verify the chemical basis of the near-infrared spectroscopy method in identification of the authenticity of the natural colored cotton,natural green cotton was used as the example.The natural green cotton and the dyed green cotton were pretreated by microwave digestion.The inductively coupled plasma emission spectroscopy(ICP-OES)and inductively coupled plasma mass spectrometry(ICP-MS)were used to determine chemical elements in the samples.The results showed that there were significant differences in the composition and content of chemical elements between natural green cotton and dyed green cotton,showing that the authenticity identification of natural colored cotton by near infrared spectroscopy is based on difference of chemical elements in test samples. |
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