Updated Model for Fast Dry Rubber Content Determination in Natural Rubber Latex Using Shortwave Near Infrared Spectroscopy

The analysis of dry rubber content (DRC) of Para rubber latex including field latex and concentrated latex, using near-infrared spectroscopy was carried out by a ultra violet/visible/near-infrared (UV/VIS/NIR) Spectrometer in transmittance mode over the wavelength range of 350–1100 nm. The original model provided the best accuracy of prediction was developed using the partial least square regression (PLSR) from the spectra which were pretreated by the smoothing and range normalization in the wavelength range of 700-950 nm. The slope, offset, correlation coefficient (r), standard error of prediction (SEP) and bias were 1.0154, -0.6286, 0.9960, 1.190% and0.0322%, respectively. The updated model was done by adding the 180 samples merged into the 280 original samples. The slope, offset, correlation coefficient (r), standard error of prediction (SEP) and bias were 1.0126, -0.3729, 0.9931, 1.2654% and 0.1103%, respectively. Therefore, it is needed to make more robust updated model by NIRS technique for determining the DRC of Para rubber latex, for both field latex and concentrated latex.

Keywords: Natural Rubber Latex, Dry Rubber Content, Shortwave, Near Infrared Spectroscopy

*Corresponding author: Email: kspanman@kmitl.ac.th