Technology
Application of Ratiometric Photometry
ARTEL's core technological strength is our proprietary Ratiometric Photometry measurement technology. While using Ratiometric Photometry for volume verification is scientifically complex, ARTEL has integrated it into easy-to-use, robust, and rapid measurement systems for liquid handling equipment. These systems, which produce traceable, standardized results, include the PCS® (Pipette Calibration System) and the MVS® (Multichannel Verification System). Laboratories use these products on a day-to-day basis to
- rapidly verify liquid transfer performance for pipettes and automated liquid handlers
- verify step-wise accuracy of serial dilution steps in microtiter plates
- train employees and evaluate operator skills
- strengthen confidence in assay results and enhance data quality
- standardize liquid handling performance assessment between methods, laboratories, and sites
- reduce instrument downtime and associated downstream costs.
Ratiometric Photometry combined with ARTEL’s expertise in dye chemistry, metrology, and low-volume liquid handling provide the foundation for our extremely accurate and precise volume verification systems. ARTEL scientists perfected this measurement platform to overcome limitations of gravimetric, fluorometric, and single-dye photometric volume verification methodologies.
Understanding the Science
ARTEL’s volume verification systems employ Ratiometric Photometry through dual-dye, dual-wavelength absorbance measurements to determine a target volume of sample solution dispensed from a pipette or liquid handler. Two colorimetric dyes, with distinct absorbance maxima at 520 nm (red) and 730 nm (blue), are used to make this measurement possible. Volume measurements are determined by applying the Beer-Lambert Law, which states that the measured absorbance of a dye is proportional to the concentration of a dye, the molar absorptivity of the dye, and the pathlength of the sample holder. If both the molar absorptivities and concentrations of the dyes are known and closely controlled, which is the case with ARTEL Sample Solutions, the law can be used to determine an unknown pathlength traversed by a photometric light beam. By measuring the pathlength through the solution and by knowing the dye concentrations in the ARTEL Sample Solutions, the unknown volume can be calculated through a series of equations.