HPLC-Agilent 1100 problems

Discussions about HPLC, CE, TLC, SFC, and other "liquid phase" separation techniques.

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Hello everyone, we have an Agilent 1100 system with a quaternary pump and we have been having a lot of problems with it during the last month. The major problem is that sometimes the equipment is not running the mobile phase composition selected by us, but is running another solvent/solvents (we checked that by introducing air into the system and obsrving the bubbles in the tubing). Sometimes, the equipment is running the mobile phase composition selected , however, the injected sample is either eluted with the mobile phase w/o being retained in the column, or some peaks are missing from the chromatogram (using samples that we have run many times before and know what exactly to expect) - we know that there is no problem with the column since we tried 3 different columns with the same results. Another problem we are having is that the solvent bottles show empty every time the equipment is turned off and have to be refilled when it is turned on, even though the method is saved before turning the instrument off (it only shows the solvent bottles are empty...the actual volume of the solvents in the bottles are unchanged). This is something that started all of a sudden w/o any changes in the instrument setting made by us and we could not fix it so far. We are not sure if those are software- or hardware- related problems, or maybe both, but we think that this might have something to do with several recent power glitches we had in the building, or defect in the multi-channel gradient valve. Has anybody experienced any of those or have a suggestion on what these poblems might be due to and how to fix them? Thanks!
Did I get this right: The pump is turned off using the switch on the front, but the solvent bottles get emty anyway? Then you have a really big leak somewhere. Look for a puddle somewhere near the instrument.
If it is a software issue: See the reference manual, page 223 ff. for how to cold start the pump to erase non-volatile memory (in short: Note the DIP switch configuration, then power off, set the DIP switches to the configuration shown on page 226, power on and off the instrument, then set the DIP switches back to the original setting).
Last possibility is that your control software is corrupted and sends wrong instructions. If you have a spare PC and some hours of time, set up a the data system on the spare PC and see if it works with this one.

Good luck
I am sorry I was not clear...it only shows the solvent bottles are empty...the actual volume of the solvents in the bottles are unchanged. Thanks!
You need to physically enter the approximate amount of solvent in the reservoir bottles (and the size of the reservoir bottles) using the software (there is no sensor).

If you have that window command selected to shut off the pump when the solvent levels get low, the software uses CALCULATIONS based upon your flow rate and amounts that you had entered as present in the reservoirs, got it?

As to other issues with Quat Pump, be sure to purge ALL FOUR channels, even though you might only be using two.
I know that the volumes have to be physically entered, but once they are entered they are not supposed to reset to zero every time the instrument is turned off (even though there is still solvent in the bottles), which is what is happening. The volumes used to start from where it left before turning the equipment off, now they don't, they reset to zero volume and I have to enter the volumes every time I turn the equipment on - not a big problem, but suggests that there is smth wrong with the equipment, especially when it is happening concurrently with the other more serious problem I described.

Thanks a lot for the help and suggestions!
Sounds like a dead battery somewhere. Instead of powering them off, try just shutting the lamp & degasser off and zeroing the pump flow rates. Does it reset if you do that?
DR wrote:
Sounds like a dead battery somewhere. Instead of powering them off, try just shutting the lamp & degasser off and zeroing the pump flow rates. Does it reset if you do that?

I tried it, it does not reset them. Only when the entire instrument is turned off, the volumes are reset. Thanks for the suggestion !
So, you've got a bad battery or capacitor serving in that same capacity (I suspect).
It like a firmware problem or application problem. Be sure not to accept ` if the solvent fnish pump shutdown`
I think it's a matter of a firmware problem !
find a word
What you describe is NOT a firmware or "instrument" problem at all. The GUI bottle filling system is a software app and has nothing to do with any hardware modules, nothing. It is software only. It sounds like you are very new to HPLC, plus purchased a USED HP/Agilent 1100-series system so are starting up a very long basic learning curve. Be patient. No one learns the basics in a few months as it takes years, with training, just to get an understanding of the systems.

Bottle filling "reset". This sounds like a training or software bug issue. The feature is not being used/set-up correctly. When you have not had professional training in how to use the ChemStation for LC software, features like this (which you do not need) can easily be mis-configured resulting in it showing empty bottles each time (would be easy to show you in person, not via the fourm). The quick answer is turn the feature OFF in the system. Which ChemStation Rev # are you using? You can check Agilent's bug report for any issues too. Make sure you have applied ALL of the patch files to your software Rev. Many bugs are fixed this way. BTW: It is separate from the methods, but you need to use "save as", never "Save", to save new methods with the new settings used.
If you have changing mobile phase composition during a run that IS NOT programmed (esp when you see bubbles), then the number 1 reason for this on a QUAT pump would be one or more leaking MCGV channels. On a used system that was not properly serviced/maintained, this is very common. Esp as the market is flooded with many broken, used/abused HP/Agilent 1100 and 1200-series system that equipment flippers and resellers push out for a quick profit. Those "refurbished" labels means nothing when the seller has no experience. To troubleshoot the MCGV as the issue, please refer to this free article for more info: "HPLC Gradient Valve / Proportioning Valve / MCGV Leaks. How to Identify Them"; https://hplctips.blogspot.com/2021/08/h ... valve.html
For the first problem, solvent moving on channels where there should be no solvent moving, that is a leaking MCGV. This can be replaced or rebuilt. New from agilent is about $2400. G1311-67701

For the solvent bottle filling resetting in the software with power cycle, I have repaired this by swapping mainboards. I did observe the battery on the old board was dead and the replacement board battery was not dead. Most likely replacing the battery will resolve. They are soldered on, so not a quick swap like waters.

If the bottles are emptying physically with pump off, could be siphoning off from an open purge valve. I always leave purge valve closed.
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