7 ago. 2017

Certified Reference Materials for Spectroscopy

A catalogue of “Starna” (www.starna.com) Certified Reference Materials for spectrometers came with the last issue of Spectroscopy Europe.
The materials have a function and a range. The function is:  The purpose of the filter (check Absorbance, check accuracy, check stray light or check the resolution. 
The range can cover the UV, Visible, NIR and FTIR zone of the electromagnetic zones.

In the case of NIR there are some filters like:

NIR Neutral Density Glass References (800 - 3200nm): To check the Absorbance accuracy and linearity pf NIR spectrometers.

Metal on Quartz filters (250 – 3200 nm): With Absorbance and Transmittance values certified at different wavelengths.

NIR Solution References (900 – 2600 nm): With 14 certified peaks for wavelength qualification purposes.

Chloroform Stray Light Cell (at approx. 2365 nm): To check Stray Light.

Polystyrene NIR References (NIR and MIR range): With 14 certified peaks in the MIR spectrum. In addition, eight peaks in the NIR spectrum. These calibration values are traceable to NIST SRM 2065.

Didymium Glass Filter (430 – 890 nm): This filter has 11 peaks covering this range (four peaks over 700 nm).

Wide Range Wavelength Reference (335 – 1945 nm): This filter 20 peaks in this range (nine of them over 700 nm). It is equivalent to NIST SRM 2065.

You can download the catalog from:

1 ago. 2017

Checking Wavelength Accuracy (XDS)

It is important to check the accuracy of the wavelength peaks using if posible a NIST Standard like in this case.

Manufacturer send a file showing the accuracy of the instrument against this standard and we have to verify periodically to see if it shifts.

The verification tell us if the deviation is more than recommend, even if the diagnostics pass. In this case, we perform an Instrument Calibration and the values come closer to the values from which the instrument leaves the factory.
Delta value is the difference between the nominal value and the found value.