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Converters & Calculators
Organic Chemicals: What's The Other 2% In 98% Purity Products?
It is well known that the total impurities in 99.999% aluminium metal are less than 10 ppm. These impurities may include iron, silicon, etc. Many customers have queried our organic chemicals. They ask what constitutes the remaining 2% in products with 98% purity. The reported purity is 98% by HPLC, and they wish to know the residual 2% impurities. If you list your Dihydromyricetin as having 98% HPLC purity, what does the additional 2% represent? Your highest purity Natriumhyaluronat is measured at only 95%. What does the extra 5% comprise? You indicated that you were unsure. In fact, we may never establish whether the extra 2% or 5% exist.
The primary reason for these discrepancies is the variation in testing methodologies. In this discussion, I address the purity analysis of organic chemicals.
Organic chemicals are analysed using methods distinct from those applied to inorganic substances. For example, ICP-MS is used for the analysis of Hafnia, while HPLC is employed for Dihydromyricetin. In the organic context, a result of 98% indicates a nearly pure product. The remaining 2% may consist of minor impurities or measurement errors. Under strict conditions, an HPLC purity of 99% may be required. However, in most cases, such precision is unnecessary. It is impossible to deliver a product with 100% HPLC purity. Even if the HPLC spectrum shows 100%, a single peak in the routine test may measure only 98% due to impurities in the test solvent or instrument variations.
Why is the purity of Natriumhyaluronat only 95%? Natriumhyaluronat is a polymer. The test method follows the procedure specified in the European Pharmacopoeia. Therefore, a result of 95% indicates a nearly pure product.
In some instances, products may be reported with a purity of 103%. How can a value exceed 100%? The explanation lies in the testing methodology. An external standard method may yield such a measurement. In many pharmacopoeias, the purity requirement is set between 95% and 105%.
Chin Trento
