Chromatography Forum

I know that typically, we choose the wavelength of max absorbance for analysis when using UV detectors. I am wondering how common it is to choose another wavelength with lower sensitivity to avoid having to perform additional dilution.

I am developing a new method and would like to use this approach, but wondering if there could be any downside that I am not considering assuming that sensitivity is not a problem and there are no interfering peaks.

I guess if you choose a part of the spectrum where the slope is very steep and your detector is not very stable, that could result in increased variability. Any other potential issues?

You can use a lower maximum or use a minimum (if they exist) in the spectrum. It is OK.
An option is to reduce the injection volume.

I should have mentioned, there are two analytes with very different Uv spectra. The original method used a wavelength where one has much higher response than the other so different dilutions were required. So in this case, decreasing injection volume won't help. I am hoping to find a wavelength where both can be in linear range with a single dilution.

I should have mentioned, there are two analytes with very different Uv spectra. The original method used a wavelength where one has much higher response than the other so different dilutions were required. So in this case, decreasing injection volume won't help. I am hoping to find a wavelength where both can be in linear range with a single dilution.

Can't you time-program a wavelength change? I'm retired but our detectors "back in the day" could do that.

Agreeing w/ ^ - so long as there's enough resolution between the peaks, a wavelength switch is frequently a good way to assay things with wildly different absorbtivities.

Do have a look at the spectrum... a local maximum is an ideal target for that non-max absorbance wavelength. The thing to avoid is a region of the spectrum where absorbance is changing rapidly.