Disclosed are photometric methods and devices for determining optical pathlength of liquid samples containing analytes dissolved or suspended in a solvent. The methods and devices rely on determining a relationship between the light absorption properties of the solvent and the optical pathlength of liquid...http://www.google.ca/patents/US6404501?utm_source=gb-gplus-sharePatent US6404501 - Determination of light absorption pathlength in a vertical-beam photometer
