Answer:
6 μL
Explanation:
To prepare a solution by a concentrated solution, we must use the equation:
C1xV1 = C2xV2, where C is the concentration, V the volume, 1 is the initial solution and 2 the final solution.
The final concentration must be 15 μg/mL with a volume of 0.1L or 100 mL. The concentration of the stock solution is 250 mg/mL. 1 mg has 1000 μg, so the concentration is 250000 μg/mL. Then:
250000xV1 = 15x100
V1 = 15/2500
V1 = 0.006 mL = 6 μL