Effect of the Near Infrared Spectrum Resolution on the Nitrogen Content Model in Green Tea
YANG Dan1, LIU Xin1*, LIU Hong-gang2, ZHANG Ying-bin1, YIN Peng1
1. Tea Research Institute of Chinese Academy of Agricultural Sciences, Tea Quality and Supervision Testing Center, Ministry of Agriculture, Hangzhou 310008, China 2. Thermo Fisher Scientific (China)，Shanghai 201206, China
Abstract：The effect of different resolutions(2，4，6，8，16 cm-1) on the near infrared spectrogram and nitrogen content model for green tea was studied. Test results showed that instrument resolution could influence the spectra quality. The higher the resolution was, the richer the information would be, but the noise would increase. With lower resolution, spectrogram would be much more smooth, but get seriously distorted, and prediction accuracy would decrease at the same time. The partial least squares model was built after spectral pretreatment. When resolution was 4 cm-1, the RMSEP value of external validation set was 0.054 6, which was obviously lower than others. The Corr.Coeff. was 0.998 2. Its prediction performance was the best and the prediction accuracy better. STDEV and RSD were 0.020 and 0.334 respectively. Resolution 4 cm-1 for near infrared spectrometer collecting green tea samples was the optimal resolution. This research can provide a reference for parameters selection when collecting green tea spectra with near infrared spectrometer，improve the stability and prediction performance of the model and promote the application and promotion of the near infrared spectroscopy for tea.
杨 丹1，刘 新1*，刘洪刚2，张颖彬1，尹 鹏1 . 近红外光谱分辨率对绿茶氮含量模型的影响 [J]. 光谱学与光谱分析, 2013, 33(07): 1786-1790.
YANG Dan1, LIU Xin1*, LIU Hong-gang2, ZHANG Ying-bin1, YIN Peng1 . Effect of the Near Infrared Spectrum Resolution on the Nitrogen Content Model in Green Tea. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2013, 33(07): 1786-1790.
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