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:
http://www.starna.com/images/reference_material_catalogue2017.pdf

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.

11 jul. 2017

Dror Sharon: This Tiny Molecular Sensor can Identify a Viagra Pill | WIR...


I am a reader of the Wired Magazine, and is nice to see how NIR technology is becoming a part of this digitalized world, so it will be amazing what this technology can bring to the future.

3 jul. 2017

Lid Adjustment - NIRS™ DS2500


The firsts DS2500 (Generation 1) don´t have this system to adjust the gap for the door, and the way to do it is more dificult. If your instrument does not have the 2 screws to remove the cover showed in the video is becouse is a "Generation 1" instrument .
The instrument showed in the video is a "Generation 2".

Considerig and check subsample variation

When analyzing a heterogeneous sample, several subsamples for a large cup are acquired, and finally an average result from all the subsamples is showed as result. Is to the average result to which we give normally importance and we compared to the lab value to know the accuracy of our measurement. Anyway is important to see the several and individual results for the different subsamples.

One reason for this is to check how homogeneous is our sample, looking to the standard deviation of the predictions for each of the constituents. But we can check that depending of the math treatment we have apply in the equation, the standard deviation of the subsample predictions change and in some cases became quite large. This is something we have to consider to make a robust calibration.
 
Remember always to look to the subsample spectra and get conclusions comparing the spectral RMS with the SD for the different subsamples.

22 jun. 2017

How to check the cooling liquid - NIRS™ DS2500


Filter Replacement - NIRS™ DS2500


Lamp Replacement - NIRS™ DS2500


Instrument Calibration - NIRS™ DS2500


Checking Temperatures in DS2500 (Lamp)



 
In order that the performance of the instrument DS2500 be optimal, we have to attend the temperature of the lamp when running the diagnostics. I consider it is fine around 35ºC.
Sometimes we find high temperatures like the one in the picture, and even seeing that the report says that is OK, this temperature can affect to the instrument itself and the results.
One of the causes that this temperature increase is that the tank of the pump has lost water, so it is a good idea to check the level, and fill it in if necessary.

Checking pump level video
Check that the pump is pumping. We should see some turbulences in the water and a small noise in the pump.
Check if the water is to dirty, or with algae’s.
Check that the fan is working, its mission is to keep cold the water and see if the filter is clean so the fan performs better its mission.

Changing the filter

It is important also the temperature of the room or laboratory where the instrument is. A higher temperature will increase also the lamp temperature.

After checking all this points, and being sure that the lamp is fine, maybe is the moment to run an instrument calibration:

Instrument Calibration