|MEASUREMENT (UDY Colorimeter)|
The UDY Colorimeter is used for the final measurement step in Protein measurement
The UDY Colorimeter uses a LED light source. Light passes through the cuvet, dye solution then through an Interference Filter to a Photodiode detector. The photodiode detector generates a small current proportional to the light intensity reaching it. Protein tests are made using a 480 nm narrow-band-pass interference filter. Acid Orange 12 dye peak absorption is near 480 nm. Because the dye absorbs 480 nm light very strongly, a special flow-through short-light path cuvet is used. This eliminates the time needed to dilute solutions 50-fold or more after the protein-dye reaction is complete. It also eliminates the dilution error and the need to wash and exchange cells (cuvets).
Setting the UDY Colorimeter to obtain the correct readings for all products is done by using a 0.660 Standard Reference Dye. Thus, the colorimeter measures the difference in the amount of dye present (unbound) in the Sample Solution after the Reagent Dye has reacted with proteins. The amount of dye remaining in the equilibrium solution (after it has reacted with proteins) is filtered into the Cuvet then the signal of light into the photodiode is converted to a direct digital readout for percent protein. Since the readings are set using Standard Reference Dye Solutions, long term calibration dependencies are eliminated. The display resolution is 0.1 and 0.01% Protein depending on how each channel is set at the factory (high and low protein ranges, respectively). Also, refer UDY Factory Colorimeter Set Up Sheet in the front of the Manual. The protein measurements follow the form, %P = A(CI - C),where A and CI are constant for specific test conditions and sample type, and C is the dye concentrating in g/L. Values for A and CI are given in tables.
The colorimeter can be used immediately after it is turned on, but it normally should be allowed to warm up about 30 minutes. Settings will be more stable after it has been warmed up.