Chromatography Forum

If I remember we use caffeine for this, as both low and high wavelength maxima are available, but I don't remember going under 200 and over 280

I think we do flow rate accuracy at two levels too

These test are done not more than once a year if everything runs smooth (system suitabilty tests of various methods are ok)

Still when I think about it you guys have some good points

one comment I want to make - "assuming your method(s) have good system suitability requirements" - which should be done on well functioning system, so I think that here in tha validation stage we have to make sure that system is doing all right

Hi guys,
This is Stephen, Wavelength accuracy is an important factor of LC detection which can have serious effects on detector response, analytical results, and inter-laboratory reproducibility. Current wavelength accuracy test procedures for LC detectors have serious limitations or are very elaborate. These new test methods are fast, simple, applicable to any detector, and cover the spectral regions most frequently employed in LC detection.

For our annual PQ we ran a series of Caffeine injection with an increasing wavelength (2 nm increments) between 228 and 300 nm.

We plotted Peak response (absorbance, y) against wavelenth (x) and located the max and min values if these were within ± 2 nm of the literature values then the instrument passed.

We have methods that use wavelengths as low at 205nm. Our PQ verifies wavelength accuracy at 205nm, 244nm, 272nm using a caffeine standard. Until now, we have been performing our PQ test each time we are replacing a lamp. Because we never saw our PQ test fail, we are considering eliminating this test in the case of lamp replacement and use the instrument built-in wavelength accuracy test instead. Doing so will minimize instruments downtime considerably; it seems to be a rational risk base approach, and our vendor seems to think that it would be sufficient testing. Of course, the performance of our detectors will continue to be evaluated during the initial validation, and re-evaluated yearly and in case of major repair using our PQ. Does that seem acceptable in a compliance point of view? What is everybody doing?

What about using holmium perchlorate for wavelength accuracy?