A reagentless and rapid method to measure water content in oils

Nondestructive Detection of Moisture Content in Palm Oil by Using Portable Vibrational Spectroscopy and Optimal Prediction Algorithms

Rapid and nondestructive measurement of moisture content in crude palm oil is essential for promoting the shelf-stability and quality. In this research, micro NIR spectrometer coupled with a multivariate calibration model was used to collect and analyse fingerprinted information from palm oil samples at different moisture contents. Several preprocessing methods such as standard normal variant (SNV), multiplicative scatter correction (MSC), Savitzky-Golay first derivative (SGD1), Savitzky-Golay second derivative (SGD2) together with partial least square (PLS) regression techniques, full PLS, interval PLS (iPLS), synergy interval PLS (SiPLS), genetic algorithm PLS (GAPLS), and successive projection algorithm PLS (SPA-PLS) were comparatively employed to construct an optimum quantitative prediction model for moisture content in crude palm oil. The models were evaluated according to the coefficient of determination and root mean square error in calibration (Rc and RMSEC) and prediction (Rp and RMSEC) set, respectively. The model SGD1 + SiPLS was the optimal novel algorithm obtained among the others with the performance of Rc = 0.968 and RMSEC = 0.468 in the calibration set and Rp = 0.956 and RMSEP = 0.361 in the prediction set. The results showed that rapid and nondestructive determination of moisture content in palm oil is feasible and this would go a long way to facilitating quality control of crude palm oil.

A new approach for measuring water concentration in oil using copper sulfate powder and infrared spectroscopy

An approach for measuring water concentration in oil, based on the use of CuSO₄ particles and infrared spectroscopy, is described. The particles interact with both dissolved water and water droplets to form the monohydrate, CuSO₄·H₂O. These particles are collected on an infrared transparent membrane and then an infrared spectrum in transmission mode is recorded. Strong interaction of the water with the CuSO₄ shifts and intensifies the water bending mode to produce a unique band at 1743 cm^-1. The method provided values which are equivalent to those measured by Karl Fischer titration over the range of 10 to 3500 mg L^-1 with a linearity R² value of > 0.99 and an average %RSD for all measurements was 6%. No matrix specific calibrations are required.