First, possible reasons for peak loss during calibration and troubleshooting methods:
1. The syringe may be faulty—replace it with a new one to verify.
2. The detector might not be properly connected or could be malfunctioning—check the connection and set values.
3. Injection temperature is too low—inspect and adjust if necessary.
4. Oven temperature is insufficient—verify and increase as needed.
5. No-load airflow issues—check the pressure regulator, look for leaks, and confirm the column flow rate.
6. Column breakage—cut off the damaged portion at the inlet or detector end and reinstall the column.
Second, leading edge peaks can occur due to:
1. Column overload—reduce injection volume.
2. Co-elution of two compounds—improve sensitivity, reduce injection volume, and lower the oven temperature by 10–20°C to enhance separation.
3. Sample condensation—check the injection port and column temperature; heating may help.
4. Sample decomposition—use a deactivated liner or lower the injector temperature.
Third, trailing peaks often result from:
1. Active sample adsorption on the inlet bushing or column—replace the bushing, or remove 1–2 turns from the column inlet and re-install.
2. Low column or injector temperature—raise the temperature (without exceeding the column’s maximum limit). Injector temperature should be 25°C higher than the highest boiling point of the sample.
3. Co-elution of two compounds—adjust sensitivity, reduce injection volume, and lower the temperature to separate peaks.
4. Column damage—replace the column.
5. Column contamination—remove 1–2 turns from the inlet and re-install for capillary analysis.
Fourth, only a solvent peak appears when:
1. Syringe issue—test with a new syringe.
2. Incorrect carrier gas flow rate—check and adjust the flow.
3. Sample is too dilute—inject a known standard and increase sensitivity or injection volume if results are good.
4. Oven temperature is too high—adjust accordingly.
5. Column cannot resolve the solvent—try a column with a thicker coating or different polarity.
6. Carrier gas leak—inspect using soapy water.
7. Sample absorbed by the column or bushing—replace the bushing, or remove 1–2 turns from the column inlet and re-install.
Fifth, wide solvent peaks may be caused by:
1. Improper column installation—reinstall the column to eliminate dead volume.
2. Poor injection technique—use fast and steady injection.
3. Injector temperature too low—increase it.
4. Incompatibility between sample solvent and detector—change the solvent.
5. Residual solvent in the column—replace the solvent.
6. Poor septum cleaning—clean or replace it.
7. Incorrect split ratio—adjust the flow rate for proper splitting.
Sixth, false peaks can occur due to:
1. Sample adsorption and desorption on the column—replace the liner, or remove 1–2 turns from the column inlet and re-install.
2. Syringe contamination—try a new syringe and clean solvent. If the false peak disappears, rinse the syringe thoroughly.
3. Large sample volume—reduce the injection volume.
4. Poor injection technique—use fast and smooth injection.
Seventh, unresolved peaks on a previously working column may be due to:
1. Incorrect column temperature—check and adjust.
2. Incorrect carrier gas flow rate—measure and adjust according to specifications.
3. Excessive injection volume—reduce the amount injected.
4. Poor injection technique—adopt a faster and more consistent method.
5. Contamination of the column or bushing—replace the bushing, or remove 1–2 turns from the column inlet and re-install.
Eighth, an unstable or irregular baseline may result from:
1. Column degradation or contamination—replace the bushing, or remove 1–2 turns from the column inlet and re-install.
2. Detector or injector contamination—clean both components.
3. Carrier gas leakage—replace the septum and check for column leaks.
4. Poor carrier gas control—ensure source pressure is sufficient (≥500 psi). If not, replace the cylinder.
5. Impure carrier gas or contaminated gas path—replace the gas cylinder and clean the tubing with a purification device.
6. Incorrect carrier gas flow rate—measure and adjust according to instrument specs.
7. Detector failure—consult the instrument manual for further checks.
8. Septum aging—replace the septum if it’s old or worn.
By addressing these common issues systematically, you can significantly improve the performance and reliability of your chromatographic system. Always refer to the manufacturer's guidelines and maintain regular maintenance to prevent such problems from recurring.
Contouring Makeup
contouring stick,contouring for beginners,contouring nose makeup,Suitable for all skin tones retouching
Guangzhou Boxuanya Cosmetics Co.Ltd. , https://www.cosmeticsbxy.com