Folin & Ciocalteu's phenol reagent

Concentration: 1.9-2.1 N.
Applicability:Suitable for determination of total protein by Lowry method.

Association.
The product is also used as part of the Folin protein concentration determination kit.

Other considerations.
Folin phenol reagent does not contain phenol. On the contrary, the reagent will react with phenolic and non-phenolic reducing substances to form chromophore that can be detected by spectrophotometry.

Application.
Folin phenol reagent is the most commonly used reagent for the determination of protein concentration in Lowry method. In this method, the protein was pretreated with copper (II) in an improved biuret (alkaline copper solution stabilized with sodium potassium tartrate). The addition of phenolic reagents produces chromoplasma that increases the absorbance between 550A and 750nm. Typically, the absorbance at the peak (750nm) or acromion (660nm) is used to quantify the protein concentration between 1 and 100mg/ml, while the absorbance at the 550nm is used to quantify the higher protein concentration. In the absence of copper, the color intensity is mainly determined by the content of tyrosine and tryptophan, and to a lesser extent by cysteine and histidine. Copper (II) has no effect on the color formation of tyrosine, tryptophan or histidine, but reduces the color formed by cysteine. Many modifications to the original determination methods have been published, including enhanced coloration, determination of the concentration of insoluble proteins, and methods to automate the experimental process. Compounds including many buffers, chelating agents, detergents and cyclic organic compounds may interfere with the detection of proteins by Lowry. Folin phenol reagent can also be used as a chromogenic agent in chromatographic operation.