The present invention includes methods of determining the volume of liquid dispensed by a dispenser. Initially, a refractive index analysis is preformed on a first liquid that has been dispensed from the dispenser in question. From the refractive index analysis, information is obtained about the volume of first liquid dispensed. The invention also includes methods for verifying the volumetric accuracy of a dispenser. The methods include dispensing a first liquid having a known refractive index into a vessel having a second liquid with a known volume and a known refractive index to form a test mixture. The refractive index of the test mixture is measured and then correlated with the refractive index of the first liquid to obtain information about the volume of first liquid dispensed. The dispensed volume is then compared to the theoretical volume of liquid dispensed by the dispenser.