Total Protein Reagents

Total Protein Reagents

Colorimetric method
ENDPOINT

PRINCIPLE

In the biuret reaction, a chelate is formed between the Cu2+ ion and the peptide bonds of the proteins in alkaline solutions to form a violet colored complex whose absorbance is measured photometrically. The intensity of the color produced is proportional to the concentration of protein in the sample.

REAGENT COMPOSITION

R1 Biuret reagent: Cupric sulfate 6 mmol/L, sodium-potassium–
tartrate 21 mmol/L, potassium iodide 6 mmol/L, sodium
hydroxide 0.75 mol/L. C R:34. Contents: 4 x 100ml
CAL Protein standard: Bovine serum albumin 7 g/dL (70 g/L).
Concentration value is traceable to Standard Reference
Material 927. Contents: 1 x 3ml

STORAGE AND STABILITY

Store at  2-8ºC.

REAGENT PREPARATION
The Reagent and Standard are ready-to-use.
SAMPLES
Serum or heparinized plasma.
Total protein is stable in serum and plasma for 1 week at room
temperature, for at least 1 month refrigerated at 2-8ºC, and for up
to 2 months at –20ºC.

MATERIALS REQUIRED

• Photometer or colorimeter capable of measuring absorbance at
  540 ± 20 nm.
• Constant temperature incubator set at 37ºC.
• Pipettes to measure reagent and samples

Total Protein Reagents per box