1. You have 1.0 ml of bovine serum albumin (BSA) at a concentration of 10 mg/ml. You want 1.0 ml of BSA at a concentration of 10 ng/ml. Describe the procedure you would use to dilute your sample to 10 ng/ml.

Careful. This is not as straightforward as it appears. Remember that you

cannot measure volumes less than 1 l accurately; therefore a serial dilution is used.

• DF = C2 / C1= 10 ng/ml / 107 ng/ml = 10^-6
• V1 = DF X V2= 10^-6 X 1,000 l = 10^-3 l

• Add 10^-3 l stock to 1.0 ml water.

• The problem we see with this method is that there is no convenient way to measure 10^-3 l accurately.

• Instead, you should perform a series of standard dilutions. For example, could do a series of three consecutive 10 ^-2 dilutions to reach a total dilution of 10^-6.