[kjmccarthy]

I need to find the concentration of a sorbic acid after it has been mixed with propionic acid. I have 135microliters of 1500ppm of propionic acid and 135microliters of 50ppm of sorbic acid. Once placing both of these in a well with a max volume of 270microliters, the sorbic acid should be diluted to some degree, decreasing the concentration. I am unsure of how to go about finding the new concentration of the sorbic acid because it is more complicated then M1V1=M2V2.

[Arkcon]

You can still figure it out.  Consider:  If you mixed 135 uL of a propionic acid solution with water, you'd know exactly how to calculate the dilution.  Just perform the calculation individually for each, and you'll have your answer.