1. No Peaks or Very Low Peaks
Possible Causes:
- Injector blockage.
- Carrier gas flow issues.
- Detector malfunction.
Solutions:
- Check and clean the injector.
- Ensure carrier gas is flowing at the correct rate.
- Verify detector settings and check for blockages or contamination.
2. Tailing Peaks
Possible Causes:
- Column contamination.
- Poor injection technique.
- Inappropriate column temperature.
Solutions:
- Clean or replace the column.
- Use a clean syringe and ensure proper injection technique.
- Adjust the column temperature according to the sample’s properties.
3. Broad Peaks
Possible Causes:
- Column overload.
- Poor column efficiency.
- Incorrect flow rate.
Solutions:
- Reduce the sample size.
- Replace the column if it has degraded.
- Optimize the carrier gas flow rate.
4. Baseline Drift
Possible Causes:
- Temperature fluctuations.
- Contaminated carrier gas.
- Detector instability.
Solutions:
- Stabilize the oven temperature.
- Use high-purity carrier gas and replace gas filters.
- Allow the detector to stabilize before use.
Troubleshooting Guide for Analytical Instruments: Atomic Absorption Spectroscopy (AAS) Faults and Solutions
1. No Signal or Low Absorbance
Possible Causes:
- Lamp alignment issues.
- Incorrect wavelength setting.
- Sample preparation issues.
Solutions:
- Realign the lamp.
- Verify and set the correct wavelength.
- Check and correct sample preparation procedures.
2. High Background Absorbance
Possible Causes:
- Matrix interferences.
- Contaminated burner or nebulizer.
- Faulty background correction.
Solutions:
- Use matrix modifiers or dilution.
- Clean the burner and nebulizer.
- Verify and adjust the background correction settings.
3. Poor Reproducibility
Possible Causes:
- Inconsistent sample introduction.
- Unstable flame or lamp.
- Contaminated reagents or samples.
Solutions:
- Ensure consistent sample introduction techniques.
- Stabilize flame conditions and replace unstable lamps.
- Use high-purity reagents and prepare samples consistently.
Troubleshooting Guide for Analytical Instruments: High-Performance Liquid Chromatography (HPLC) Faults and Solutions
1. No Peaks
Possible Causes:
- Pump not delivering solvent.
- Detector not functioning.
- Blocked column.
Solutions:
- Check pump operation and prime if necessary.
- Ensure detector is on and set correctly.
- Flush or replace the column.
2. Irregular Peak Shapes
Possible Causes:
- Air bubbles in the system.
- Column issues.
- Sample solvent incompatible with mobile phase.
Solutions:
- Degas solvents and ensure a bubble-free system.
- Check column for blockages or damage.
- Match sample solvent to the mobile phase.
3. High Backpressure
Possible Causes:
- Blocked frit or column.
- Mobile phase contamination.
- Pump malfunction.
Solutions:
- Clean or replace the frit and column.
- Filter and degas the mobile phase.
- Check and maintain the pump.
4. Baseline Noise
Possible Causes:
- Detector lamp issues.
- Mobile phase impurities.
- System leaks.
Solutions:
- Replace the detector lamp if aged.
- Use high-purity solvents and clean mobile phase bottles.
- Check and fix any system leaks.
Troubleshooting Guide for Analytical Instruments: Spectrophotometers Faults and Solutions
1. No Signal or Low Absorbance
Possible Causes:
- Light source failure.
- Incorrect wavelength setting.
- Sample cell misalignment.
Solutions:
- Replace the light source.
- Set the correct wavelength.
- Align the sample cell properly.
2. High Background Absorbance
Possible Causes:
- Dirty sample cell.
- Contaminated solvents or samples.
- Instrument baseline drift.
Solutions:
- Clean the sample cell thoroughly.
- Use high-purity solvents and prepare clean samples.
- Perform a baseline correction.
3. Unstable Readings
Possible Causes:
- Temperature fluctuations.
- Light source instability.
- Electrical noise.
Solutions:
- Maintain a stable room temperature.
- Replace unstable light sources.
- Ensure proper grounding and minimize electrical noise.
4. Poor Reproducibility
Possible Causes:
- Inconsistent sample handling.
- Instrument calibration issues.
- Variations in light path.
Solutions:
- Standardize sample handling procedures.
- Calibrate the instrument regularly.
- Ensure consistent positioning of the sample cell.
By following these troubleshooting guidelines, you can effectively diagnose and resolve common issues with GC, AAS, HPLC, and spectrophotometers, ensuring reliable and accurate analytical results.
Article by: Hakeem Owolabi
hakeem@aasning.com