Is it possible to calculate the molar extinction coefficient from a single absorbance measurement on one solution of known concentration?

Yes, it is possible to calculate the molar extinction coefficient (ε) from a single absorbance measurement if you have a solution of known concentration. According to Beer-Lambert Law, the relationship is given by A = εcl, where A is the absorbance, c is the concentration, and l is the path length of the cuvette. Rearranging this equation, you can derive ε by using the formula ε = A / (cl), provided you know the absorbance, concentration, and path length.