These specifications are for the Go Direct® Mini GC™ (GDX-GC)
Specifications and User Guide
If you have the original Mini GC, the specifications are listed here: Specifications and User Guide and Mini Gas Chromatograph Troubleshooting and FAQs
If you have the Mini GC Plus, the specifications are listed here: Specifications and User Guide and Mini GC Plus Gas Chromatograph Troubleshooting and FAQs
Troubleshooting
General Use Tips
- Use Approved Compounds Only: Always refer to the list of acceptable compounds in the user guide before injecting new samples.
- Avoid High-Water Samples: Do not inject samples that contain more than 5% water. Water can damage the detector.
- Hamilton Syringe Note: The syringe shipped with the device has a brown bumper on the needle. Do not remove this bumper—it protects the injection port.
Also see Best Practice Techniques for Vernier gas chromatographs
Troubleshooting Common Issues
- Inconsistent Flow:
- Likely Cause: Worn or damaged septum.
- Solution: Replace the septum.
- Inconsistent Peak Areas:
- Likely Cause: Irregular injection volume or worn septum.
- Solution: Check your injection technique and replace the septum.
- No Communication:
- Likely Cause: Software mismatch or cable/Bluetooth connection.
- Solution: Be sure you’re using Instrumental Analysis software. Check USB cables or verify Bluetooth pairing.
- No Power:
- Likely Cause: Power cord or switch issue.
- Solution: Confirm that power plugs are fully inserted and the switch is turned on.
Top Questions
1. What detector does the Go Direct Mini GC use?
The Go Direct Mini GC uses a chemiresistive carbon nanotube (CNT) detector. This is different from the MEMS or thermal conductivity detectors used in older models. The CNT detector offers high sensitivity to both polar and nonpolar organic compounds.
2. Why is the y-axis labeled “Normalized Response” instead of mV?
Because the CNT detector measures resistance change rather than voltage output, the signal is displayed as “Normalized Response”, not millivolts. This allows for comparison of peak shapes and retention times, but it is not intended for quantifying absolute concentration values without calibration.
3. Can I display the signal in millivolts?
No. The output from the CNT detector does not translate directly to millivolts, so the system does not support mV display like the older Mini GC Plus.
4. I’m seeing some baseline drift—what should I do?
Baseline drift is expected with chemiresistive detectors, but here are some tips to manage it:
- Pay attention to the Y-Axis scale: If your sample has a low signal, even small baseline drift will appear more significant. Try increasing the injection volume or adjusting your temperature and pressure settings to improve peak size.
- Use an isothermal temperature profile: If you’re analyzing a single compound, there’s no need for a temperature ramp. A constant temperature minimizes drift. Only use a ramp when separating complex mixtures.
- Subtract the baseline: If your signal contains consistent electronic noise or drift, using the baseline subtraction feature in the software can improve the clarity and accuracy of your chromatogram.
5. How can I improve peak shapes?
- Review the temperature and pressure settings. These may need to be optimized for the Go Direct unit (they differ from Mini GC Plus settings).
- Start with our published experiments and example profiles in the Go Direct Mini GC Compound Library
- Use injection volumes between 0.1–0.3 μL and ensure consistent injection technique.
- Replace the septum regularly if you’re seeing split peaks or tailing.
6. What’s the best way to inject a gas or volatile sample?
All samples—liquid or gas—must be injected using a syringe through the septum.
Can I inject a gas into the Vernier gas chromatographs?
7. How do I maintain the unit?
- Septum: Replace regularly (every ~40–50 injections).
- Column: Run a high-temp clean cycle with a volatile like acetone to remove residue.
- Power: Use a short USB cable or a powered USB hub if you’re experiencing communication issues.
8. What software do I use?
The Go Direct Mini GC usesLabQuest 2 or LabQuest 3 or Instrumental Analysis, our free software compatible with Windows, macOS, iOS, Android and Chrome. It is not supported in Logger Pro.
9. Can I use Logger Pro with this GC?
No. Logger Pro is not compatible with the Go Direct Mini GC. Use Instrumental Analysis or LabQuest 2 or 3 instead.
10. My Mini GC is not reaching the set pressure.
This could indicate a clogged column or septum leak. Try:
- Replacing the septum.
- Running a cleaning cycle with acetone at high temperature.
- Checking the power connection and USB cable.
11. Can students use Go Direct Mini GC alongside older Mini GC Plus units?
Yes, but the column and detector are different, so this may cause confusion. Review our guide:
How is the Go Direct Mini GC different than previous versions of the Mini GC?
RELATED TIL ENTRIES
How is the Go Direct Mini GC different than previous versions of the Mini GC?
Go Direct Mini GC Compound Library
Best Practice Techniques for Vernier gas chromatographs
Can I inject water into Vernier gas chromatographs?
Can I inject a gas into the Vernier gas chromatographs?
What size needle do Vernier gas chromatographs require?
Where can I order the syringe for Vernier gas chromatographs?
The peak heights on my Vernier gas chromatograph are lower than they were previously.
My Vernier gas chromatograph pressure won't get above 15 kPa.
I need to ship a Vernier gas chromatograph to Vernier for repair. How should I package it?
Can I purchase a replacement power supply for my Vernier gas chromatograph?
My Go Direct Mini GC displays "Error 2"
RELATED VERNIER PRODUCTS
GC Septa (package of 4) (GC-SEP)
Mini GC 1 μL Hamilton Syringe (GC-SYR-MIC)
Replacement Power Supply for Vernier Mini Gas Chromatographs (GC2-MINI-PS)
For column and/or sensor replacement, email chemistry@vernier.com for assistance.