User Guide

For an introduction to the application and use of Certified Reference Materials in absorption spectrophotometry


This Reference Material can be used to qualify the wavelength calibration, in the ultraviolet and visible regions of the spectrum (240 nm - 795 nm) of spectrophotometers with spectral bandwidths of 3 nm or less.

Description and Discussion

Holmium oxide and didymium (neodymium & praseodymium) oxide in 10% v/v perchloric acid, permanently sealed by heat fusion into a 10 mm far UV quartz cuvette.

Holmium and didymium (neodymium & praseodymium) oxides in perchloric acid have been separately used for the validation of the wavelength scale of UV and visible spectrophotometers for many years. Now, these materials are available from Starna as a combined reference, providing useful peaks that are interference-free over its whole wavelength range from 240 to 795 nm.

14 peaks are certified, with nominal values: 241, 287, 361, 416, 444, 482, 485, 522, 537, 575, 641, 732, 740 and 794nm.

Note: The above values are for guidance only. Because the absorption bands are asymmetric, measured values will bespectral bandwidth dependent. The Calibration Certificateaccompanying each Reference gives actual values measured at bandwidths of 0.10, 0.25, 0.50, 1.00, 1.50,2.00 and 3.00, 4.00 and 5.00 nm, and only these certified values should be used for instrument qualification. On request, Starna can provide certified values at otherwavelengths and bandwidth values.

Typical spectra



Catalogue Number

COMPOUND Catalogue  Number

Holmium/Didymium liquid cell