Determination of the residual organic solvent content in the extracted aqueous phase

Thread Content

The method of \"determining the organic solvent content in the raffinate using ultraviolet spectrophotometry\" was tried, but the results were not satisfactory. After measuring the absorbance, the solution was poured back into the test tube, shaken, and then poured into a cuvette for further measurement; the absorbance value changed significantly. After pouring it back and shaking it again for measurement, the value changed by more than 0.01 once more. This process was repeated several times, but it was not possible to obtain a standard curve. The sample measurements showed the same variation, ruling out instrument-related issues. It was observed that fine particles were floating in the cuvette; this increased after filtration through a 0.22 micron filter. I would appreciate guidance on the reason for this, or suggestions for alternative testing methods