What is difference between assay and purity?

04/06/2019 Off By admin

What is difference between assay and purity?

The main difference between assay and purity is that an assay is the determination of one of the main component in a sample whereas purity is the determination of impurities in a sample. Assay and purity are two types of measurements used to determine the components of a sample.

What is chromatographic purity?

Simply, chromatographic purity is a test ( usually TLC or HPLC ) where the sample is compared to some standards, and the spots/peaks of any impurities detected must not exceed the prescribed limits for size and number.

What is the difference between potency and purity?

Purity includes but is not limited to relative freedom from residual moisture or other volatile substances and pyrogenic substances. The word potency is interpreted to mean the specific ability or capacity of the product, as indicated by appropriate laboratory tests, to yield a given result.

What is chromatographic assay?

A chromatographic immunoassay is a technique in which an antibody or antibody-related agent is used as part of a chromatographic system for the isolation or measurement of a specific target.

Why we do assay by HPLC?

HPLC methods help analyze drug concentration in biological fluids to evaluate ADME (absorption, distribution, metabolism, and excretion) profile of the drug. The drug discovery phase also involves pharmacology and toxicology assessments of the drug compounds.

How do you calculate purity?

Percentage purity of a substance can be calculated by dividing the mass of the pure chemical by the total mass of the sample, and then multiplying this number by 100.

What is purity in HPLC?

High Performance Liquid Chromatography (HPLC) We use this method to determine the purity of our products. The ratio of the desired product to that of the combined impurities is expressed as a % purity. We will typically state that a product is say >99% (by HPLC).

How is standard purity calculated?

The purity of the standard is calculated to 95.55% (purity = 100% – (2.5% x 0.98) – 2%).

What is the best chromatographic method?

Chromatography methods based on partition are very effective on separation, and identification of small molecules as amino acids, carbohydrates, and fatty acids. However, affinity chromatographies (ie. ion-exchange chromatography) are more effective in the separation of macromolecules as nucleic acids, and proteins.

Can assay be more than 100%?

Assay values that exceed 100% are not uncommon in the Pharmaceutical industry where formulators use pure API drug substances to which they add inactive ingredients, referred to as an excipient, to arrive at a target concentration of a formulated drug product.

How are gas and liquid chromatography used to determine purity?

Both gas chromatography (GC) and liquid chromatography (LC) are capable of determining the purity of s sample. However, analytical standards are not available to measure most types of impurities. Therefore, it can be difficult to determine or quantify the exact amount of those impurities in the sample.

How are chemical assays used to determine purity?

Chemical assays are done using techniques like chromatography, titrations, etc. Assays are done to determine the purity of metals in an ore. One such method is the wet method where the sample is dissolved in an acid to extract the metal. Sometimes a dry method can also be used where the metal is mixed with a substance to reduce the melting point.

How is the potency of an assay calculated?

It is calculated against standard. It may be of following types: 1) On as is basis = (Area of sample / Area of standard) x (conc. of standard / conc. of sample) x potency or assay of standard. 2) On anhydrous basis = (Assay on as is basis / 100 – moisture) x 100. 3) On dried basis = (Assay on as is basis / 100 – LOD) x 100. Potency:

Which is used to determine the purity of a sample?

One of the main analytical method used to determine the purity of a sample is chromatography. Both gas chromatography (GC) and liquid chromatography (LC) are capable of determining the purity of s sample.