Certified calibration standards for reliable measurement results
To supply accurate results over the long run, spectrophotometers need to be calibrated in regular intervals. Using UV/Vis calibration standards from the accredited Hellma calibration lab guarantees that the calibration operations performed are traceable to the NIST (National Institute of Standards and Technology) primary standards. This ensures that internal quality requirements are fully met, and that the international comparability of measurement results is guaranteed.

Glass filter: For inspection of the spectrophotometers in respect of:
Photometrical accuracy and wavelength accuracy in the visible spectral range (VIS range). Full set consisting of: Holmium oxide glass filter and 3 neutral glass filters
Filters also available separately.

Liquid filter: Complete set for inspection of the spectrophotometers pursuant to the European Pharmacopoeia in respect of:
Wavelength accuracy, photometrical accuracy, stray light behavior, resolution power.
Complete set consisting of: Potassium chloride and reference filter, toluol in hexane and reference filter; potassium dichromate in HCIO4 and reference filter, holmium oxide in perchloric acid
Filters also available separately.

Regular calibration
Usually, glass filters are recalibrated every 12 months in the frist two years of use, and every 24 months after that. Liquid filters should be recalibrated after 12 months at the latest. The recalibration intervals should be specified by the operating company as they depend upon the actual conditions of use in the laboratory.