Selecting the Solvent in the Determination of Water in Erythromycin

To compare the effects of different solvents on the determination of water in erythromycin and explain why anhydrous methanol solvent makes the experiment result higher, Karl Fisher method is used to determine the water in erythromycin , with anhydrous methanol as solvent or anhydrous pyridine . And the result is compared with that of Weightlessness method. It turns out that experiment result with anhydrous pyridine as solvent is closer to weightlessness method. So it is better to determine the water in erythromycin with anhydrous pyridine solvent.