FAQ: "I am trying to look through some of the technical literature for both the XE and VIS UltraScan colorimeters. I know that the lab bought VIS instruments because they were supposed to have similar (identical?) optical setups, and we were hoping to transition from one to the other seamlessly. However, I have found that when we had some elevated levels of fluorescent materials in the resins we are testing, I see very strong changes in the instrument bias between XE and VIS instruments. This shouldn't be happening as far as I can tell, and I was wondering if you could speak to any concrete differences between the two models."
The UltraScan VIS and UltraScan XE are very similar sensors and should have very similar measurements on normal samples.
UV fluorescent samples are not normal in that they are optically active and interact with the UV content of the sensor lamp. They require UV control to minimize this effect.
The simplest form of UV control is to insert a UV cut-off filter inserted IN the light path cutting off the UV illumination. Both models have a UV cut-off filter. The UltraScan XE has a 420 nm UV cut-off filter as standard. The UltraScan VIS has a 400 nm UV cut-off filter as standard and an optional D02-1013-749 USVIS-UV Exclusion Filter Kit that consists of a 420 nm UV cut-off filter.
This optional D02-1013-749 USVIS-UV Exclusion Filter Kit places an additional 420 nm UV Filter on the same filter flag as the standard 400 nm UV Filter that comes with the USVIS. EZMQC software is designed to recognize its presence and make it available for 420 nm IN for UV exclusion at 420 nm.
For fluorescent samples, the best option for agreement would be a USXE with standard 420 UV cut-off filter IN the path, and UltraScan VIS with optional D02-1013-749 420 nm UV cut-off filter IN the path. This would result in the closest agreement in UV exclusion.
You would want to test these configurations on your resin samples but they should achieve good inter-sensor agreement between UltraScan XE and UltraScan VIS.