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Filter Validation System for Kemtrak Photometers

One of the perennial headaches for users of inline photometers is validating that they are working correctly when in process. There are various strategies for this but all require a trained person to correlate and interpret the results.

The Kemtrak solution resolves this headache with a simple, off-the-shelf solution that anyone can use. A good inline photometer will provide absorbance (or transmission) values that relate to actual absorbance at the wavelength they are operating at and not values that are correlated to actual absorbance. As long as this is the case, the same neutral density filter standards that are used to test and adjust laboratory bench top instruments (such as spectrometers and spectrophotometers) can be used to test inline photometers. Simply put, using a high quality inline photometer such as a Kemtrak DCP007 will allow validation in the same way as a bench top unit – you get the exact same measurement from a Kemtrak unit in process as you do with samples in your onsite laboratory or QC lab.

Kemtrak provide two different methods for using standard filters in the light measurement circuit

1) A built-in cuvette holder in the flow cell itself.
2) Where access is difficult, a separate unit for installation in the light circuit is available.

These filters are inserted directly into the light circuit and the absorbance measured can be seen in the analyzer menu screen or through the analyzer software interface. Absorbance is additive, so even if the analyzer is in process and providing the process is stable, the filter can still be inserted and the extra absorbance in the measurement it creates noted. Kemtrak units have a huge range – typically twice that of incandescent or gas lamp powered devices – so even if the process measurement is already quite high (and depending upon the absorbance standard value) the unit can still be validated.

The Kemtrak validation method relies upon independent, third party supplied and certified standard filters to give the utmost confidence in the readings from the unit.