While performing the assays for the LDH kinetics experiment, you will pipet 25ul of 250 ug/ml LDH into 975 ul of assay buffer (Tris, Lactate, and NAD). What is the final concentration of LDH in the assay?

6.25 μg/mL

Explanation:

When a dilution is made, the mass of the solute is conserved (Lavoiser's law), so the mass pipetted will be the mass in the assay. The mass is the concentration (C) multiplied by the volume (V). If the pipet solution is called 1, and the assay 2:

m1 = m2

C1*V1 = C2*V2

C1 = 250 μg/mL

V1 = 25 μL

V2 = 975 μL + 25 μL = 1000 μL (is the final volume of the assay after the addition of LDH)

250*25 = C2*1000

C2 = 6.25 μg/mL