TMI (Trace Metallic Impurity)

TMI – (Trace Metallic Impurity) - TMI analysis is a test often performed to determine the cleanliness of products like starting materials or reagents. This is a very extensive and in-depth analysis of (typically) low concentration elements that are not expected or intended in the chemical and could have the potential to disrupt certified values if used to manufacture products. For example, if we want a CRM with 1ppm lead but our acid has an impurity of 1ppm lead, the product will contain twice as much analyte as intended.

• This type of analysis is particularly time consuming and difficult due to the large concentration gap between the trace level impurity elements and the bulk or primary analyte(s) in the starting material. For example, we may analyze a 50,000 ppm aluminum solution in search of part per billion level contaminants – low level contaminants are difficult to detect, relative to the high concentration of Al.