text: # Prepare standard concentrations of protein of 1, 5, 7.5 and 10 µg/mL. Prepare a blank of NaCl only. Prepare a series of sample dilutions.
  # Add 100 µL of each of the above to separate tubes (use microcentrifuge tubes) and add 1.0 mL of Coomassie Blue to each tube.
  # Turn on and adjust a spectrophotometer to a wavelength of 595 nm, and blank the spectrophotometer using 1.5 mL cuvettes or use a mobile smartphone camera (RGBradford method).
  # Wait 2 minutes and read the absorbance of each standard and sample at 595 nm.
  # Plot the absorbance of the standards vs. their concentration. Compute the extinction coefficient and calculate the concentrations of the unknown samples.