Summary and Exam
GC Troubleshooting Course
Course Conclusion
Thank you for participating in our online course, Troubleshooting in Gas Chromatography. We hope the modules have equipped you with practical strategies to maximise instrument uptime, avoid common errors, and efficiently diagnose and resolve issues when they arise.
Over the 12 modules, we’ve covered a wide range of GC troubleshooting topics, including:
- The foundational steps of a successful troubleshooting process — from identifying symptoms to isolating the root cause.
- Causes and solutions for missing peaks, broad or tailing peaks, and how to achieve sharp, symmetrical peak shapes.
- How to address baseline issues such as excessive noise, drift, high background, and random spiking — often caused by contamination.
- Tackling peak shape anomalies like carryover, fronting, split peaks, and peak overlap.
- Strategies for improving peak resolution and separation.
- Identifying and resolving issues behind retention time variability and response variability — two of the most common yet often overlooked challenges in GC.
Key Takeaways: Troubleshooting Principles
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 basics first: Confirm power, gas supply, pressure levels, and method parameters.
2. Compare good vs. bad runs: This can offer valuable clues, especially if a method worked previously.
3. Change only one variable at a time: This isolates the impact of each adjustment and avoids confusion.
4. Keep detailed records: Document every step you take — this helps not just you, but anyone else involved in troubleshooting..
By applying these principles consistently, you’ll gain a deeper understanding of your GC system and become more confident and capable in resolving even complex problems.
Daily Maintenance Checklist
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.
Good luck — and thank you again for choosing this course.
Your Shimadzu GC Team