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qihua.chen@yinizhisci.com
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Shanghai Yinzhi Scientific Instrument Co., Ltd
Pre holiday maintenance and shutdown guide for second-hand liquid phase equipment
Date: 2024-06-07Read: 9
During the Dragon Boat Festival, Loong Boat races, and the fragrance of zongzi wafts. "While enjoying the small holiday, we should also pay attention to the laboratory equipment! Here are some tips for pre holiday second-hand liquid phase equipment.
Short term and long-term shutdown of equipment
Short term shutdown:
1. Removing harmful mobile phases from pumps and systems:
(1) Rinse the buffer salt in the system with water, as solvent evaporation can leave harmful precipitates such as salt crystals.
(2) Remove chloroform and its prepared solutions from the system to prevent decomposition and formation of hydrochloric acid.
2. After removing the harmful mobile phase, rinse the pump and system with isopropanol. When the instrument is stopped, rinse the pump, column, and flow cell with 60/40 methanol/water for 30 minutes (the column should be compatible with methanol/water).
3. Turn off the power supply of the pump, detector, and sampler.
Long term shutdown:
1. After the sample measurement is completed, turn off the deuterium lamp first to reduce losses.
2. Cleaning system and manual injection valve: Depending on the sample being prepared, the method of shutdown cleaning varies. The specific methods are as follows:
(1) If the mobile phase is an organic phase, it only includes: methanol, acetonitrile, isopropanol, water, etc; When cleaning, simply clean with 100% methanol for 40-60 minutes to turn off the machine. Replace the solvent bottle corresponding to the aqueous phase with methanol and adjust the pump ratio to 95% for flushing.
(2) If the mobile phase contains buffer salts such as weak acids, weak bases (strong acids and bases must not be injected into the machine!), acetic acid, ammonium acetatePhosphoric acid, ammonia water, triethylamine, phosphate, etc. When cleaning, it is necessary to clean with 95% water and 5% methanol for 80-100 minutes, and then clean with 100% methanol for 40 minutes before shutting down. Replace the solvent bottle containing buffer salt with water phase, adjust the pump ratio to 95%, clean for 80-100 minutes, then replace the solvent bottle containing water phase with methanol, keep the pump ratio unchanged, and clean for 40 minutes before shutting down.
(3) The cleaning principle for the injection valve is the same as above, except that it needs to be cleaned twice with cleaning solution in both the laod and inject settings. The injection valve must not remain between Laod and Inject.
(4) The ultimate principle of cleaning is to store enough methanol in each pipeline (preferably filled with 100% methanol) to prevent mold growth. Therefore, in the final stage of cleaning, it is best to replace all infusion bottles with methanol and repeat the process.
3. After cleaning, turn off the constant flow pump in the workstation.
4. Then turn off the power supply of the detector, pump A, pump B, and column box in sequence.
5. Back up important data in the workstation in advance to prevent data loss. Turn off the workstation, computer, and power supply.
chromatographic column
The maintenance of liquid phase is basically the maintenance of the chromatographic column. Before shutdown, rinse the chromatographic column thoroughly according to the last experimental conditions. When cleaning the chromatographic column, it is not recommended to use pure water. Adding 5% methanol can ensure wetting, otherwise the carbon chain of the chromatographic column will collapse and damage the column.
Please follow the following replacement principle for flushing:
Reverse phase system: buffer salt ->water ->organic solvent
Positive phase system: Positive phase solvent ->Column storage solvent
After rinsing the chromatographic column, it does not need to be removed. If the chromatographic column must be removed, in order to ensure that the packing of the chromatographic column is not damaged, plugs should be screwed on both ends of the removed chromatographic column, and the pipeline should be sealed with a sleeve.
