Test Methods

Biuret Assay

The Biuret Assay, also known as the Piotrowski Test, is a biochemical assay that allows one to accurately quantify protein concentration within the range of 5-150 mg/mL. The protein sample, irrespective of its composition, is measured through absorbance spectroscopy at 540 nm in conjunction with a known protein concentration sample. 

Bicinchoninic Acid Assay (BCA)

The Bicinchoninic Acid Assay (BCA), also referred to as the Smiths' Assay, is a biochemical assay designed by Paul Smith in 1985. (Smith, et al., [7])  This assay uses colorimetric detection and quantification to determine the total concentration of protein in a solution by exhibiting a measurable color change. Applications of this assay include studying protein-protein interactions, estimating percent recovery of membrane proteins from cell extracts, high-throughput screening of fusion proteins, measuring column fractions after affinity chromatography and measuring protein covalently bound to agarose supports and protein adsorbed to multiwell plates.

Standard Time-Kill Testing

A Standard Time-Kill, often referred to as STK, Suspension Test, or Time-Kill Kinetics Assay, is an in vitro test which measures the changes in a population of aerobic microorganisms in a pre-determined sampling time while antimicrobial properties are present.  This test method is often used to measure antimicrobial activity in hand sanitizers, antiseptic wound gels, mouth washes, and other products that are expected to have microbiocidal properties [4]. Standard Time-Kill methods are based on the American Society for Testing and Materials method, Standard Guide for Assessment of Antimicrobial Activity Using a Time-Kill Procedure (E2315-16) [1].