The molar absorbance coefficient for PNP is 18,000 M-1cm-1. If the absorbance of PNP is 0.629 at pH 10 and a wavelength of 400 nm, what is the concentration (in µM) of this sample? Remember the path length is 1 cm and this sample was not diluted.
Say you set up another PNP standard curve and then measured the absorbance of a sample of PNP of unknown concentration. The absorbance value of this sample was 0.362. This sample was not diluted, so DF = 1. If the equation of the standard curve's line was y = 0.0092x + 0.0471, calculate the concentration of PNP in this sample.
Calculate how you would make a 4-fold dilution of stock PNP solution (200 mM). The final volume of the diluted solution must be 4.0 mL. What are the volumes of stock PNP and buffer required to make this dilution?