The problem of solvent residue is a frequent occurrence of packaging bag quality issues. Soft packaging factories often encounter various problems when conducting solvent residue testing. If not resolved in a timely manner, it is easy to cause test results errors. The common problems and solutions are discussed below.
1、 Peak loss during calibration with standard samples
1. There is a problem with the sampler, please verify with a new one.
2. If the detector is not connected or does not work, check the set value.
3. The injection temperature is too low. Check the temperature and adjust it as needed.
4. The temperature of the column box is too low. Check the temperature and adjust it as needed.
5. Without carrier gas flow rate, check the pressure regulator and check for leaks to verify the flow rate at the inlet of the column box.
6. If the column box breaks, it can be remedied if it is at the inlet end of the column box or at the end of the detector. Cut off the broken part of the column box and reinstall it.
2、 The curve shows a leading edge peak
1. The column box is overloaded, reducing the injection volume.
2. Two compounds are co eluted to improve sensitivity and reduce injection volume, resulting in a temperature decrease of 10-20 degrees.
3. Sample condensation, check the temperature of the injection port and column box, and increase the temperature if necessary.
4. Decompose the sample and lower the temperature of the injector.
3、 Trailing peak on the curve
1. The injector liner or column box has adsorbed active samples, and the liner should be replaced. If the problem cannot be solved, remove 1-2 turns from the intake end of the column box and reinstall it.
2. If the temperature of the column box or injector is too low, the temperature should be increased (do not exceed the maximum temperature of the column box). The temperature of the injector should be 25 degrees higher than the highest boiling point of the sample.
3. Two compounds are co eluted to improve sensitivity, reduce injection volume, or reduce temperature by 10-20 degrees to separate peaks.
4. The column box is damaged and should be replaced.
5. If the column box is contaminated, remove 1-2 circles from the inlet end of the column box and reinstall it.
4、 The curve only has solvent peaks
1. There is a problem with the sampler and a new one should be used for verification.
2. Incorrect carrier gas flow rate (too low), the flow rate should be checked.
3. The sample is too thin, and a known sample should be injected to improve sensitivity or increase injection volume.
4. The temperature of the column box is too high. Check the temperature and adjust it as needed.
5. The column box cannot resolve the components from the solvent peak, so replace the column box with a thicker coating or different polarity.
6. If there is a carrier gas leak, the leak should be checked (using soapy water).
7. The sample is adsorbed by the column box or injector liner, and the liner should be replaced. If the problem cannot be solved, remove 1-2 turns from the inlet end of the column box and reinstall it.
5、 Wide solvent peak appears on the curve
1. Due to improper installation of the column box, resulting in a dead volume at the injection port, the column box should be reinstalled.
2. The injection technology is poor (injection is too slow), and fast and stable injection technology should be used.
3. The temperature of the injector is too low, and the temperature of the injector should be increased.
5. There is residual sample solvent inside the column box, and the sample solvent should be replaced.
6. Improper cleaning of the spacer should be adjusted or cleaned.
7. Incorrect split ratio (insufficient split exhaust flow rate), flow rate should be adjusted.
6、 False peaks appear on the curve
1. The column box adsorbs samples and the liner should be replaced. If the problem cannot be solved, remove 1-2 turns from the injection port end of the column box and reinstall it.
2. If the sampler is contaminated, try using a new sampler and clean solvent. If the false peak disappears, rinse the sampler several times.
3. The sample size is too large, and the injection amount should be reduced.
4. Poor injection technology (slow injection): Adopting fast and stable injection technology.
7、 Unresolved peaks appear in the well functioning column box
1. The temperature of the column box is incorrect, and the temperature should be checked and adjusted.
2. Incorrect carrier gas flow rate should be checked and adjusted.
3. The sample injection volume is too large and should be reduced.
4. The level of injection technology is too poor (injection is too slow), and fast and stable injection technology should be used.
5. The column box and liner are contaminated and the liner should be replaced. If the problem cannot be solved, remove 1-2 turns from the inlet end of the column box and reinstall it.
8、 Irregular or unstable baseline
1. The column box is contaminated and the liner should be replaced. If the problem cannot be solved, remove 1-2 turns from the inlet end of the column box and reinstall it.
2. If the detector or injector is contaminated, the detector and injector should be cleaned.
3. If the carrier gas leaks, the spacer should be replaced and the column box should be checked for leaks.
4. The carrier gas control is not coordinated, and it is necessary to check whether the carrier gas source pressure is sufficient. If the pressure is ≤ 500psi, please replace the gas cylinder.
5. If the carrier gas has impurities or air path pollution, the gas cylinder should be replaced and the metal tube should be cleaned using a carrier gas purification device.
6. The carrier gas flow rate is not within the maximum or minimum limit range of the instrument, and the flow rate should be measured and verified according to the technical indicators in the user manual.
7. If there is a problem with the detector, it should be checked according to the instrument manual.