Albumin Assay, BCG Method
Bromocresol green is a dye that is found to form a blue-green complex
when reacted with albumin.
Procedure:
1. Label 8 clean, dry, large test tubes as indicated in the table below, and place them into
a test tube rack.
2. Fill each of the tubes as indicated in the table. Vortex the tubes to mix their contents.
mL
BCG
2% Std
4% Std
6% Std
8% Std
10% Std
Unk T1
Unk T2
Total
0%
5
2%
5
0.02
4%
5
6%
5
8%
5
10%
5
Unk T1
5
Unk T2
5
0.02
0.02
0.02
0.02
0.02
5.0
5.02
5.02
5.02
5.02
5.02
5.02
3. Iincubate for 10 minutes at room temperature.
4. Set the wavelength of your spectrophotometer to 637nm.
5. Obtain 8 rectangular cuvets/spectronic 20 tubes. Label them appropriately, and
fill them with the appropriate solution from you large test tubes.
7. Read and record the absorbances/%T’s for each tube, using the saline tube as the
blank.
Tube
BCG
2%
4%
6%
8%
10%
Unk T1
Unk T2
Results :
Abs.
%T
The following should be contained in your lab report:
Your Unknown Number
A graph of Absorbance vs. Standard Concentration
Record the concentration for each trial of the unknown, then average them.
0.02
5.02
Calculate the % difference for each unknown sample:
100 x [unk. value - average]/average
Any observations/anomalies encountered during the performance of this experiment.