I need to calculate the molarity of Bromothymol Blue (BTB), and I can only use M1V1 = M2V2. I did a dilution, using a pH 8.0 Phosphate Buffer. Before...

I need to calculate the molarity of Bromothymol Blue (BTB), and I can only use M1V1 = M2V2. I did a dilution, using a pH 8.0 Phosphate Buffer. Before dilution, the molarity of BTB is 23.2 µM. 

Volume of BTB = 0.025 L Volume of Phospahte Buffer = 0.005 L