Summary and Exam
GC Troubleshooting Course
Course Conclusion
Thank you for participating in our online course, ‘Troubleshooting in GC’. We hope it has equipped you with practical tools to maximise system uptime, prevent errors, and quickly diagnose and resolve issues. In the past 12 course modules, we’ve covered a wide range of troubleshooting topics:
- We learnt about the basic steps that should be part of every troubleshooting process and found out what causes no peaks to appear at all.
- We discovered what lies behind broad peaks and tailing peaks, and how to resolve them to get your peaks looking narrow and symmetrical.
- We dealt with the various contamination issues that typically give rise to baseline issues, including a high baseline and an unstable baseline (including spiking, excessive noise and baseline drift).
- We learnt about the main causes of carryover, and what to do about fronting peaks.
- We covered the ways to overcome poor peak resolution and peak overlap, as well as how to deal with split peaks.
- And finally, we learnt about the numerous causes of response variability and retention time variability.
However, troubleshooting is an ongoing learning process, and it’s always possible that you might encounter challenges that we’ve not addressed here.
Therefore, to ensure that you give yourself the best chance of success, always follow the key troubleshooting principles:
1. Check the essentials such as power, protocols and gases.
2. Determine exactly what’s going wrong – comparing ‘good’ and ‘bad’ runs may give you useful clues.
3. When it comes to implementing troubleshooting tips, only change one thing at a time!
4. Write down everything, to help yourself and anyone you may later decide to ask.
By applying these strategies, we think you’ll develop a deeper understanding of your GC system and gain valuable hands-on experience – making future challenges all the easier.
Daily Maintenance Considerations
To complement the troubleshooting principles you’ve learned, adopting a few simple daily checks can go a long way toward preventing problems before they arise. Here are five quick things to review at the start of each day:
1. Gas lines – is there sufficient carrier/detector gas availability and pressure? Check pressure gauge on the cylinder or manifold to ensure gas is being supplied to the instrument within the specified range (usually 300 – 900 kPa). If using a hydrogen generator, does this have sufficient deionised water?
2. Injection – is the syringe in good condition? Check that the syringe is moving freely without sticking and if required, clean with fresh solvent (ideally with polar and non-polar variants). Check that the solvent wash vials are sufficiently filled to reduce possible carryover.
3. Consumables – when were the septum and liner last replaced? Some software’s have counters to help you to schedule regular maintenance. If this is not available, check your maintenance log. It is recommended that septa and liners are changed after 100 sample injections. If this limit is exceeded, then it may be worth checking the condition of the septum and liner and replacing if required.
4. Column – have I been seeing higher baselines in my recent sample analysis? A column condition/clean-up/bake-out should help. Raise the column oven temperature to 10 degrees lower than the column’s recommended max temperature and hold for an hour to see improvement. The inlet/detector ends of the column could also be trimmed and re-fitted with new ferrules.
5. Test injection – regularly analysing a standard containing a known compound, will give useful information on the state of the instrument. Record and trend parameters such as retention time, peak response and peak shape to help you to plan preventative maintenance.
Incorporating these checks into your daily routine will reduce downtime and help maintain consistent performance.
Thank you again for taking part in our course! If you now feel ready to take the test, then click below to start. To pass and gain your completion certificate, you’ll need to gain 75% of the total available points. We wish you the best of luck!
Please note that certificates are issued periodically and may take 2-3 weeks to arrive.
Your Shimadzu LC Team
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