Chromatography Forum

I have a LC agilent 1100 system. I have just reinstalled chemstation software. But after finishing installation, the system do not work properly. The UV peak of the same sample is short than before about 10 folds. So I can not detect the small amount of interest subtance like before. What should I do??????

The reinstallation of chemstation should not cause sensitivity issues. Check you have inputted the method conditions correctly, especially the inj volume and the wavelength.

I have inputted the same method and the same wavelength 215nm. What can cause sensitivity issues?

Are you using an external integrator? If so, check that the voltage in the 'Analog Output Range' under the 'Control' menu of the VWD module matches what you had originally - if your are using an external integrator, your detector setting may have reverted to 0.1 volts instead of 1 volt, hence the 10-fold decrease in signal intensity.

I have reverted the detector setting to 1 volt but nothing happen, the signal is still low.

Hi
You must check your UV Lamp Life and it's numbers of Ignitions.
when your HPLC is Online,in Diagnosis Tab(the last tab in left-down corner of chemstation) you can see in shematic in uv update parameter.
Probebly your problem is due to the Low Intensity of Uv Lamp.
Good luck .

Is the peak area also ~10 fold lower?

Try changing the slit size and frequency

There is no slit width adjustment on the 1100 VWD, and sampling frequency shouldn't have that much to do with a 10x decrease in peak height (unless you had an astounding increase in baseline 'fuzziness' due to extreme oversampling and were looking at a very small peak in the first place).. Did you ensure that your lamp type is defined correctly? The VWD allows for the installation of the G1314-60100 or the 2140-0590 lamps, and perhaps you have a different lamp type installed than is currently specified?