PRODUCTION OF CERTIFIED REFERENCE MATERIAL OF HOLMIUM(III) OXIDE IN AMPOULES

This work reports the development of a certified reference material (CRM) of holmium(III) oxide Ho2O3 in acidic solution for the wavelength scale calibration of UV-Vis spectrophotometers. A 4.0% Ho2O3 solution was gravimetrically prepared in 10% perchloric acid and bottled in 5.0 mL glass ampoules. Homogeneity, stability and characterization were assessed according to ISO 17034 and ISO Guide 35. The material certification was undertaken by two laboratories by using UV-Vis spectrophotometry for characterization of the 14 peaks of minimum transmittance of Ho2O3, using a spectral bandwidth of 1.00 nm and a scanning speed of 30.0 nm min‒1. The material property values in wavelength (nm) were obtained for these 14 peaks, together with the expanded uncertainty (U) of 0.12 nm, for a coverage factor (k = 2.00) corresponding to a probability of approximately 95%, which took into account the standard uncertainties obtained in each study performed for the certification of the produced reference material.