Chromatographic sample bottleIt is a core consumable for storing test samples in analysis and detection such as liquid chromatography (HPLC) and gas chromatography (GC). Its cleanliness directly affects the stability of chromatographic baseline, peak shape quality, and accuracy of detection results. If there are residual pollutants or impurities in the bottle, it is highly likely to cause problems such as ghost peaks and baseline drift. Therefore, it is crucial to clean and maintain the chromatographic sample bottle properly.
1、 Preparation before cleaning
Classification and sorting
Separate the sample bottles according to their material (glass, polypropylene) and specifications (1.5mL, 2mL, etc.) to avoid scratching or deformation caused by mixing different materials.
Pick out damaged, cracked, or deformed sample bottles and eliminate them directly to prevent poor sealing or difficult removal of residues.
Consumables splitting
Completely separate the sample bottle from the bottle cap and spacer. It is recommended to clean the spacer separately or replace it directly (repeatedly used spacers are prone to aging and adsorption of impurities).
If there are high concentration sample residues or insoluble substances in the bottle, the waste liquid can be poured out first and rinsed with pure water for a preliminary rinse.
2、 Cleaning methods for different levels of pollution
1. Conventional mild pollution (applicable to residual water-soluble samples)
For ordinary samples suitable for daily testing (such as organic acids, sugars, inorganic salt solutions), the steps are as follows:
Add 3/4 volume of pure water to the sample bottle, ultrasonically clean for 5-10 minutes, shake and discard the waste liquid.
Repeat the above operation 2-3 times until the poured water is clear and free of visible impurities.
Finally, rinse the inner wall 2-3 times with chromatographic grade methanol or acetonitrile to remove trace organic residues other than water-soluble impurities.
Invert on dust-free filter paper and air dry naturally in a fume hood.
2. Moderate pollution (applicable to organic samples and oil residues)
Suitable for sample residues containing organic solvents, oils, proteins, etc. that are difficult to dissolve in water. The steps are as follows:
Soak the sample bottle in anhydrous ethanol or acetone for 30 minutes to soften the organic residue.
Pour out the soaking solution, add an appropriate amount of neutral detergent solution (such as 5% detergent solution), and ultrasonically clean for 15-20 minutes.
Rinse the inner wall of the bottle repeatedly with pure water until there is no foam, to ensure that the detergent is completely residual.
Wash twice with chromatography grade methanol, invert and dry or place in an oven, and dry at a low temperature of * * 40-60 ℃ * * (to avoid glass bottle explosion caused by high temperature).
3. Severe pollution (applicable to residual samples with strong adsorption and difficult degradation)
Suitable for stubborn residues such as pesticide residues, antibiotics, and high concentration buffer salts. The steps are as follows:
Prepare specialized cleaning solution: Choose according to the type of pollutant, such as alkaline pollutants soaked in 5% dilute nitric acid; Soak organic stubborn residues in a 10% methanol hydrochloric acid mixture.
Fully immerse the sample bottle in the cleaning solution and soak for 2-4 hours (or ultrasonic assisted cleaning for 10 minutes), taking care to avoid prolonged contact of strong acids and alkalis with the polypropylene material sample bottle.
Take out the sample bottle and rinse it repeatedly with pure water until neutral (pH test paper can be used for detection) to ensure that there is no residue in the cleaning solution.
Wash sequentially with chromatographic grade ethanol and methanol, dry and set aside for later use.
Attention: After cleaning with strong acid and alkali, it must be thoroughly rinsed, otherwise residual acid and alkali will corrode the chromatographic column or affect the pH environment for detection.
3、 Drying and storage after cleaning
Drying method selection
Natural drying: Suitable for glass sample bottles, inverted in a dust-free environment to prevent dust from falling in. It takes a long time but is not easy to damage the bottle body.
Oven drying: The temperature should be controlled at * * ≤ 60 ℃ * *, and most of the water in the bottle should be drained first to prevent glass breakage caused by sudden high temperature heating; It is not recommended to dry the polypropylene sample bottle to avoid deformation.
Nitrogen blow drying: suitable for emergency use scenarios, using high-purity nitrogen to quickly blow the inside of the bottle, efficiently and without secondary pollution.
Saving techniques
After cleaning and drying, the sample bottles should be placed in a clean storage box with a lid to avoid dust and laboratory aerosol contamination.
The bottle cap and new spacer should be separately sealed and stored, and assembled before use to prevent the spacer from adsorbing impurities.
Separate the sample bottles cleaned from different batches, label them properly, and prioritize using the batch that was cleaned first.
4、 Daily maintenance precautions
Avoid cross contamination
Sample bottles for different types of samples should be used separately, for example, sample bottles for pesticide residue detection and food nutrient content detection should not be mixed.
Cleaning tools (ultrasonic cleaning tank, tweezers, beaker) should be cleaned regularly to avoid contamination of sample bottles with impurities carried by the tools.
Maintenance of spacers and bottle caps
Silicone spacer is recommended for one-time use. After multiple punctures, the spacer is prone to damage, debris, sample contamination, or blockage of the injection needle.
If the screw cap has loose threads or poor sealing, it should be replaced in a timely manner to prevent sample evaporation or external impurities from entering.
Regular sampling inspection
After cleaning, several sample bottles can be randomly selected, and blank solvents (such as mobile phase) can be added to test the baseline situation on the machine. If abnormal peaks appear, they need to be cleaned again.
5、 Cleaning taboos
Do not use hard brushes or steel wire balls to scrubChromatographic sample bottleThe inner wall is prone to scratches, and pollutants may remain at the scratch site, making it difficult to completely remove.
Polypropylene sample bottles should not come into contact with high temperatures (>60 ℃) and strong oxidants to avoid material deformation or aging.
Sample bottles containing highly toxic samples such as cyanide and mercury need to be treated harmlessly according to hazardous waste disposal standards before cleaning.