1. From the 0.25% stock solution of Bromophenol Blue(BPB), prepare 8mL of 0.1% BPB working solution in a large test tube. When preparing solutions, always transfer water to the tube first, then add any additional reagents.

2. Prepare six dilutions of the 0.1% BPB working solution as indicated in the table below. Be sure you actually watch the liquid gets transferred to the tube from your pipette tip, especially when manipulating small volumes. Mix the diluted dye samples well by vortexing.

3. Once the dilutions have been prepared, transfer each solution to a cuvette and use the UV spectrophotometer to measure the absorbance at 590nm.

4. Complete the table with your calculations and measurements of the dye solution.

 

% Volume Volume Total % Absorbance BPBinitial Dilution of 0.1% of H20 Final BPBinal (590 nm) Volume 0.1% BPB 0.1% BPB 0.1% BPB 0.1% 0.1% BPB 0.1% BPB 1:10000 1:50 1:100 1:250 1:500 1:1000