We place a dissolved sample of a mixture in the autosampler unit and pump it through the analytical column. By analyzing printed HPLC plots, we can verify proper ingredient ratios in a given mixture. We also use HPLC to examine the purity and potency of raw materials. For example, we use liquid chromatography to measure the parthenolide content in Feverfew and the ephedra content in Chinese Ephedra. Any ash that remains after the burn is mineral content or dirt, and this is weighed.
Every herb has a characteristic mineral content and a corresponding typical ash content.
If, in testing, we find an ash content that is significantly higher than the typical ash content, we suspect the presence of dirt or some other foreign inorganic material. Dirt is a common problem, especially with herbs harvested from plant roots. If harvesters do not take the time to completely clean the dirt from their tools, NSP will reject their herbs. A high AIA value may indicate that the herb sample is contaminated with metal particles. Some raw materials that come from eastern Europe may be contaminated with radiation from the Chernobyl nuclear power plant disaster.