Further information regarding solubility can be found here What are the likely impurities in my product?
• The Certificate of Analysis for a product and a particular lot will show what testing is performed in quality control and what impurities are present. Unless there is testing for specific impurities included in the Specification for a product we will not, generally, have any information on what impurities are present. Levels of any impurities that we do not test for, may vary from batch to batch.