Quantify a relate substance with different wavelenght

Discussions about methods, troubleshooting and best practices across both pharmaceutical and biopharmaceutical analysis.

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Hello everybody!

I'm new to the chromatography world and my question must be very easy to solve... But I need some light!

So... I'm following a method in order to monitor some impurities during a stability study of a pharmaceutical product.

The method indicates few impurities, with their RRT, specification, among other information.

All of them are calculated based on the calibration curve obtained with the standard of the API, which is obtained at 254 nm..
But only 2 impurities must be quantified using a 210 nm wavelength...
My struggle is that I'm not able to use Empower in order to quantify these two impurities at 210 nm, using a calibration curve obtained at 254 nm...
I suppose I must create a different processing method for these 2 impurities and I've tried, but unsuccessfully.
Hi michele_k

It is very simple, you have to run your standards at 210 nm and plot a new curve for the impurities.


We have used this approach successfully to quantify THC and CBD in one run in hemp and marijuana extract. Concentrations of both is very different in both - hemp sample has 98%+ CBD and less than 0.1% THC, and marijuana extracts have 90% THC/THCA and less than 0.1% CBD. So for each of the runs we sued one wavelength to monitor THC and another wavelength for CBD in marijuana products, it was switched for hemp analysis. We were able to cover a wide range. We did not want to go to 210 nm with it in order to avoid seeing some of the smaller components which were not critical for the analysis.
Vlad Orlovsky
HELIX Chromatography
My opinions might be bias, but I have about 1000 examples to support them. Check our website for new science and applications
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