Holmium Oxide Liquid Filter
| Description | Holmium oxide filter, liquid filter, certified |
| Use | Assessment of wavelength accuracy in both UV and visible range from 240 nm to 650 nm, at a spectral bandwidth between 0.1 nm and 3 nm |
| Material | Holmium oxide dissolved in perchloric acid and sealed in Hellma precision cells made from quartz SUPRASIL® |
667-UV5 Holmium oxide dissolved in perchloric acid
Holmium oxide dissolved in perchloric acid is highly suitable for checking the wavelength accuracy of spectrophotometers both in the UV and the visible range. It shows a spectrum with a multitude of highly defined peaks. The heights and positions of these peaks are dependent on and will vary with the chosen slit width of the measuring instrument.
Typical spectrum of holmium oxide dissolved in perchloric acid, measured with a slit width of 1 nm.
The filter with the holmium perchlorate solution is placed into the beam path of the measuring instrument. The smallest slit width has to be used for this measuring (e.g. 1 nm). The smoothing (damping) has to be adjusted to a relatively high level. Alternatively the average of several measurements can be calculated to avoid evaluation errors. The precise peak positions at 241.15 nm, 287.15 nm, 361.5 nm and 536.3 nm are measured and compared with the values given in the certificate. Deviation should not be more than ±1 nm in the ultraviolet range or more than ±3 nm in the visible range. If available the reference filter 667-UV14 filled with perchloric acid can be placed in the reference beam path.
This suppresses the background of the spectrum without influencing the peak position. Ideally the measurement is performed with the slit width specified in the certificate. If this is not possible, choose the smallest possible slit width.
| Type | Substance | Theoretical Wavelength (nm) According to Pharm. Eur. |
| 667-UV5 | Holmium Perchlorate in Perchloric Acid | 241.15, 287.15, 361.5, 536.3 |