Chromatography Forum

Hello,

We have been having a weird issue with our Agilent 6430 MS.
We use the system primarily for toxicology (drug testing) and it has been working fine for years, However, about a month ago most of our analyte ion ratios dropped down to near 0. compounds most affected were morphine, cocaine and fentanyl but pretty much all ion ratios dropped drastically to the point where the system is unusable.

The system does pass autotune but we did notice a steep decrease of abundance in the higher M/Z regions which is not reflected at the lowest masses which seem ok.

We had a tech replace the main board and calibrate the instrument and for about a week afterwards the system worked better but the ion ratios still did not recover to previous values. For example, our ion ratio for morphine used to be close to 100, then it dropped to 0.4. After repair, the ratios recovered to 13. A couple of days ago, the ratios dropped below 0.4 again.

Some of our analytes (Meth or Amphetamine) seem less affected by the ratio drop and they happen to be our lowest mass analytes.

At this point, our tech is confused and it feels like we've tried everything without success. Any direction or suggestion anyone could give would be most appreciated. Thanks.

Seems a the ion optics collected some dirt over the years. Try to clean the High Pressure ion optics funnel and the ion optics assembly. Details found in the Agilent 6400 series triple quad lc ms maintenance guide. Please do not disassemble the ion optics more than described in the manual, very sensitive to the geometry.
The mainboard change was a money waste.

Thank you, the main board replacement took care of some other issues we were having. Mainly High Vac error and "mainboard 1 lens driver power supply cannot maintain the voltage." After that, the warnings went away but we still don't have the ion ratios. We will clean the optics as suggested. Thanks again, Happy Holidays!