What is the Difference Between Assay and Purity?

The main difference between assay and purity is that an assay is the determination of one of the main components in a sample, whereas purity is the determination of impurities in a sample. Both assay and purity are used to measure the components of a sample, but they serve different purposes and are expressed differently.

• Assay: An assay experimentally determines the presence, amount, or functional activity of a target entity (the analyte) in a sample. It aims to measure the analyte or main target component present in the sample, and the measurement may be quantitative, semi-quantitative, qualitative, or functional. Assays can be single target or multiplex, and they can be used in various fields, such as pharmacological, biochemical, and immunological research.
• Purity: Purity refers to the absence of impurities in a sample and is usually expressed as a percentage. It aims to accurately reflect the purity characteristics of the sample. Chromatography is the primary analytical method used to determine the purity of a sample, with both liquid chromatography and gas chromatography being capable of measuring the purity of a sample.

In summary, an assay focuses on measuring the main component or analyte in a sample, while purity focuses on the absence of impurities in the sample. Both measurements are essential in various fields, such as pharmaceuticals, chemistry, and biology, to ensure the quality and accuracy of the samples being analyzed.

Comparative Table: Assay vs Purity

The difference between assay and purity can be understood through the following table:

In summary, an assay is a measurement of the main component or analyte in a sample, while purity is a measurement of the impurities in a sample. Assays can be quantitative or qualitative, and they can measure single or multiple targets. On the other hand, purity is a quantitative measurement, typically determined using chromatography techniques.