Can I make UV-Vis calibrant in the lab? I have a Thermo Nanodrop 1000 spectrometer that I have reason to believe is out of calibration. After consulting the manual, it appears as though there is a way to check the calibration of the spectrometer using a premade CF-1 calibration solution. This solution itself appears to be aqueous potassium dichromate, but I cannot find the concentration and exact specifications of the solution online. I was curious if anyone has attempted to make the calibrant from reagent they had in lab, and if so, what exactly does one use to make the solution?
The last time I calibrated an absorbance spectrometer, it was one I made from parts (for an undergraduate Instrumental Analysis teaching laboratory) and I used a 0.0509 M holmium chloride solution I prepared. The visible region spectrum I obtained is here:



Holmium solutions are well known as UV-Vis calibration standards and you can purchase from, e.g., www.starnacells.com. Below is a screenshot from the Starna Cells web site, indicating that their ready-made sealed holmium reference standard cuvette cells have NIST traceability. Evidently, they are good down to 241.0 nm. I would have purchased one, if I had had the money at the time, but the solution I prepared worked well and was not particularly expensive. Erbium and praseodymium solutions also work well.

Sharp peaks in an aqueous solution at room temperature are always nice. Maybe this will help you!