BCA stands for Bicinchoninic Acid Assay, which is a protein quantification method based on the biuret principle. Under alkaline conditions, the protein peptide bond reduces Cu²⁺ in copper sulfate to Cu⁺, and then BCA chelates Cu⁺ to form a purple complex that strongly absorbs light at a wavelength of 562 nm. The color of the chelate is related to the protein concentration, and the amount of Cu²⁺ or Cu⁺ obtained is proportional to the amount of protein present in the solution, so the protein concentration to be measured can be obtained by measuring the protein absorbance value.

This kit is characterized by ease of operation, high stability, high sensitivity, and high compatibility. The lower limit of detection concentration was 25 μg/mL, the minimum amount of detected protein was 0.5 μg, and the volume of samples to be measured was 1-20 μL. There is a good linear relationship in the concentration range of 50-2000 μg/mL.