GPC Operation, Troubleshooting and Maintenance notes

Updated as of February 5, 2003

Running an GPC acquisition

Preparing your sample:
1. concentration: 1mg/ml in THF
2. pass through a 0.2 to 1 micron filter (Teflon).
3. add about 2ml in the vial for autosampler
4. Add flow rate marker if necessary
5. Add a pure THF sample as your last sample to flush out the exhaust tubing on the autosampler


Setting up instrument:
1. Signing in the logbook with your name, sample info.
2. Turn on flow rate to 1ml/min and wait for at least 30 min before injection
3. Before starting injection, flush the RI detector.
4. Load GPC Online acquisition program
5. Choose appropriate workbook(s) for the right detector(s)
6. Ready the detectors by click on the Ready buttons in the program
7. Program the autosampler by inputting the starting and ending vial #.
8. In the GPC acquisition program, create your list of samples with appropriate batch name and sample name
9. Click on Start on the autosampler to start acquisition

During the acquisition:
1. Monitor the THF level in the reservoir
2. Monitor the THF level in the waste bottle
3. Monitor the status of the autosampler and ensure no error has stopped the autosampler.


After your experiment:

1. Process your data using GPC Offline program
2. turn the flow rate down to 0.05ml/min
3. empty the waste bottle
4. Sign out in the logbook and note the operating pump pressure.

 

Troubleshooting

If no sample peak comes out in the detector reading:
1. Check the pump flow rate and make sure it is 1ml/min.
2. Check the pump pressure and make sure it is ON and in a reasonable range, currently 8.x MPa.
3. Check the exhaust tubing of the autosampler and make sure it is not stuck with polymer residue. Clip or exchange the tubing if necessary.
4. Check if you have enough sample in the vial and if the sample level reduces after an injection.

 

Maintenance

For the person-in-charge:
1. THF level. Introduction of air into the columns could be very bad. So keep an eye on the level of THF in the reservoir especially when running long acquisitions.
2. Waste bottle. Make sure it does not overflow. Check periodically.
3. Check the exhaust tubing of the autosampler and make sure it is not stuck with polymer residue. Clip or exchange the tubing if necessary.
4. Calibration. GPC should be calibrated periodically, no less than once per month. Use appropriate standard sample for each column set and discard those points, which have MW larger than the upper limit of the column. For column sets with Mixed-C (or D) AND 100A columns, order 2 should be used for fitting. Calibrant solution should be kept in the Flammable fridge and can be used up to a couple of weeks