Feasibility study on the evaluation of the dry rubber content of field and concentrated latex of Para rubber by diffuse reflectance near infrared spectroscopy

The analysis of the dry rubber content (DRC) of Para rubber latex, including field latex and concentrated latex, using near infrared spectroscopy was conducted using a Fourier transform near infrared (FT-NIR) spectrometer in diffuse reflection mode over the wavenumber range of 4000-10,000 cm ^-1. The proposed method is useful for industrial purposes. The best model was developed using the partial least square regression (PLSR) from the spectra, which were pretreated using the 2^nd derivative method, where the correlation (r²), standard error of prediction (SEP) and bias were 0.997, 0.3398% and -0.0239%, respectively. The ratio of standard deviation (SD) to SEP of the reference data in the prediction sample set (RPD) was 18.18 and the ratio of the range to the SEP of the prediction set (RER) was 74.4. The model was validated using a new batch of samples and the prediction performance was good with an r² of 0.999, a SEP of 0.3898% and a bias of -0.0008%. Therefore, the NIR spectroscopy technique can be used as an accurate and rapid method for estimating the DRC of Para rubber latex for both field and concentrated latex. © IM Publications LLP 2013. All rights reserved.