First, the possible reasons for peak loss during calibration and troubleshooting methods:
1. A faulty syringe may be the cause—replace it with a new one to verify.
2. Check if the detector is properly connected or functioning; adjust the set value if necessary.
3. If the injection temperature is too low, check and increase it as needed.
4. An oven temperature that is too low can also affect results—adjust accordingly.
5. No-load airflow or pressure regulator issues may exist—check the pressure and look for leaks. Ensure the column flow rate is correct.
6. A broken column may be the issue; if the break occurs at the inlet or detector end, cut off the damaged section and reinstall the column.
Second, leading edge peaks may occur due to several factors:
1. Column overload—reduce the injection volume.
2. Co-elution of two compounds—improve sensitivity, reduce injection volume, and lower the temperature by 10–20°C to enhance separation.
3. Sample condensation—check the injection port and column temperature; if necessary, heat them up.
4. Sample decomposition—use a deactivated injector liner or lower the injector temperature.
Third, trailing peaks can be caused by:
1. Adsorption of active samples by the inlet bushing or column—replace the bushing. If the problem persists, remove 1–2 turns from the column inlet and re-install.
2. Low column or injector temperature—raise the temperature (but do not exceed the column’s maximum limit). The injector temperature should be 25°C higher than the highest boiling point of the sample.
3. Co-elution of two compounds—increase sensitivity, reduce injection volume, and lower the temperature to separate the peaks.
4. Damaged column—replace it.
5. Contaminated column—remove 1–2 turns from the inlet and re-install for capillary analysis.
Fourth, only solvent peaks may appear due to:
1. A faulty syringe—test with a new one.
2. Incorrect carrier gas flow rate—check and adjust if needed.
3. The sample is too dilute—inject a known standard to confirm. If the result is good, increase sensitivity or injection volume.
4. Oven temperature too high—check and adjust.
5. The column cannot resolve the component—replace it with 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. If not resolved, 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. Interaction between the solvent and detector—try a different solvent.
5. Residual solvent in the column—change the solvent.
6. Poor septum cleaning—clean or replace it.
7. Incorrect split ratio—adjust the flow rate.
Sixth, false peaks can occur due to:
1. Sample adsorption and desorption on the column—replace the liner. If unresolved, 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 injection volume—reduce the amount injected.
4. Poor injection technique—use a fast and smooth method.
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—verify and adjust.
3. Excessive injection volume—reduce it.
4. Poor injection technique—use rapid and steady injection.
5. Contamination of the column or bushing—replace the bushing. If not resolved, remove 1–2 turns from the column inlet and re-install.
Eighth, an unstable or irregular baseline may be caused by:
1. Column degradation or pollution—replace the bushing. If not fixed, remove 1–2 turns from the column inlet and re-install.
2. Contaminated detector or injector—clean both.
3. Carrier gas leakage—replace the septum and check for column leaks.
4. Inconsistent carrier gas control—check the source pressure. If it's below 500 psi, replace the cylinder.
5. Impurities in the carrier gas or contaminated gas path—replace the cylinder and clean the tubing with a purification device.
6. Incorrect carrier gas flow rate—measure and verify against the instrument manual.
7. Detector malfunction—refer to the instrument manual for troubleshooting.
8. Septum aging—replace the septum if necessary.
Eye Shadow
Easy to color eye shadow,Fine and delicate eye shadow,Moderate hard and soft eye shadow,Fine silty eye shadow,Easy to paint eye shadow
Guangzhou Boxuanya Cosmetics Co.Ltd. , https://www.cosmeticsbxy.com