Three-Fibre-Based Diffuse Reflectance Spectroscopy for Estimation of Total Solid Content in Natural Rubber Latex

Abstract

It is shown that three-fibre-based diffuse reflectance spectroscopy, based on spatially resolved near infrared spectroscopy in the wavelength range 850–1060 nm, is a promising method for the measurement of quality in natural rubber latex samples. Absorbance ratios were defined as the ratio of light intensity detected at distances ρ and ρ + Δ from the emitter fibre. A relative absorbance ratio γ was then calculated using the absorbance ratios at three wavelengths. Parameter γ had a strong linear correlation with total solid content in latex (range 0.3′-0.6 g g−1) with a coefficient of determination value of 0.98 and root mean square error for total solid content of 0.014 g g−1. Although the near infrared spectra measured by conventional transmission or reflectance spectroscopy were highly affected by the scattering coefficient in the sample, simulation results in this study showed that the effects of scattering in the samples on γ can be reduced.