Aspectrics introduces a new application note: MultiComponent 2750 EP-NIR analyser achieves precise measurement of water in ethanol, particularly when ethanol concentrations are 90% or greater
Determining the percentage of water contained in ethanol is especially important during the purification process of ethanol when the percentage of water needs to be minimized for ethanol to be as absolute as possible.
Designed to respond to scientists' needs working in the process industry, this is an efficient and cost-effective solution for measuring water content in ethanol.
The innovative EP-NIR analyser is showcased at Pittcon 2007, Chicago, February 26 - March 1, 2007.
The application, note entitled 'Measurement of water in ethanol - using an Aspectics MC2750 EP-NIR for concentrations of ethanol greater than 90% v/v', shows how the Aspectrics MultiComponent 2750 EP-NIR analyser, when coupled to an external halogen NIR source and an extended range 2mm pathlength process transmission multimode fibre probe, is able to quantify the percentage volume of water in ethanol.
The findings of this analysis are detailed in the new, free-of-charge application note available to download.
All spectra were collected using Aspectrics's RTSS Chemometrics software package.
Denatured corn-based ethanol samples diluted with distilled water to concentrations ranging from 0.2 to 10.0% were used.
In order to quantitate unknown samples, a multivariate principal component regression (PCR) quant model was developed from the NIR spectra of all samples.
The results of the analysis demonstrated strong correlations between concentrations in the spectral range of 1.4-1.55nm and 1.85-2.00nm and in the C-OH region between 2.00 and 2.2nm.
The precision of the calibration may be ascertained through the RMSEP of the validation set, which was 0.14% v/v.
At the maximum concentration for water, this value is consistent with the precision of the reference method (1.2% relative).
A majority of this deviation originates from the 8.0% sample, which suggests a pipetting error during sample preparation.
Furthermore, the experiment highlighted that the accuracy of study is highly dependent on the precision of the reference method.
The new application further stresses the unique capabilities of the MultiComponent 2750 EP-NIR analyser, which has already demonstrated a high degree of sensitivity due to extremely low instrumental noise, long-term photometric response stability and superior scan to scan wavelength reproducibility.
