Chemists and researchers wonder if they may reuse chromatography vials and closures. Well, at least after a thorough cleaning in laboratory dishwashers designed for lab glassware.
If you reused the vials, earlier chemicals (attached to the wall’s surface) might interfere with your study. When it comes to impurity testing, reusing vials might be a problem for impurity calculations. There’s a chance you’ll get an extra peak if there’s a danger of contamination.
In this article, find out how to clean the vials properly. Also, you will find out what happens when the vials get contaminated.
Can I Reuse the Vials?
Personally, if you want to reuse, you should consider utilizing vial inserts.
- Need fewer samples
- Generate less waste when discarded
There’s also the benefit of not needing to dispose of a large amount of vial cleaning solvent.
Even with inserts, it’s a good idea to run a blank after every injection to ensure no contamination.
If the vials you’re using have screw tops (usually it comes to use HPLC), be sure you don’t reuse the caps.
It is for the best to continuously purchase in a new vial. If nothing, especially when your analyte concentrations are predicted to be either very high or very low.
Re-running those samples will cost you more in terms of:
1. time.
2. materials.
3. and energy than vial recycling.
Most likely, standard laboratory processes demand that vials and closures are consumable products. Therefore, it would be best to dispose of the vials after each use, especially when employing glass autosampler vials.
You can clean the autosampler vials in laboratory dishwashers. Scientists often use dishwashers for washing laboratory glassware. The washed vials are then used in the laboratory to save money on consumables.
The cleaning is damaging the glass vials. Also, this process is inefficient at eliminating contaminants from the vial surface.
This contamination is unexpected and creates interference peaks in LC and GC chromatography applications. Unpredictable contamination is a common source of unexplainable assay failures, necessitating the re-analysis of whole sample runs.
You will see later in this article the results of reusing old vials, so keep reading for more information.
But, in general, yes, you can use them. But, there are a lot of aspects you have to consider. For example, you need to know how to clean them properly.
How to Clean the Vials
There are a lot of methods of cleaning the vials and closures, and here are five of them.
Method 1
1. Rinse the vial with tap water many times
2. Ultrasound for 15 minutes in a beaker with clear water.
3. After changing the water, ultrasound for 15 minutes.
4. Immerse it in water-ethanol in a beaker.
5. Lastly, let the natural air-dry the vial.
Method 2
1. Rinse with water before soaking in sulfate potassium chromite lotion.
2. Infiltrate the vial for more than 4 hours with medical alcohol.
3. Ultrasound for half an hour.
4. Pour out medical alcohol.
5. Use water ultrasound for half an hour.
6. Rinse with water after drying it.
Method 3
1. Soak in methanol (pure color spectrum) for 20 minutes. Then do the ultrasonic cleaning, then methanol dry.
2. Fill the chromatographic sample vial halfway with water. Then do the ultrasonic cleaning for 20 minutes and drain the water.
3. Following the drying of the chromatographic sample bottle
Method 4
1. First, soak for 24 hours in a strong oxidation cleaning solvent (heavy potassium chromate).
2. Then clean three times with deionized water in ultrasonic conditions,
3. Lastly, clean once with methanol. Dry it afterward.
4. You must replace the bottle pad with a new one, especially when assessing pesticide residues. Otherwise, you will indeed affect the quantitative findings.
Method 5
1. Reverse-drying chromatographic sample in-bottle test solution.
2. Soak it in 95% alcohol, wash it twice with ultrasonic, and dry it. You must dry it since alcohol quickly gets into a 1.5mL container and dissolves most organic solvents.
3. Fill with clean water and use ultrasound twice.
4. Pour the lotion into the drying container and bake for 1-2 hours at 110 degrees Celsius. Make sure you’re not baking at a high temperature.
5. Refrigeration and preservation.
It is advisable to get sample vials of clear and amber colors at once when purchasing.
For example, your laboratory must complete two projects. The projects are A and B.
The A project uses a clear sample vial the first time, whereas the B project uses a amber sample vial. After the test, you clean the vial according to the above method.
In the second experiment, use the amber color for the A project and the clear color for the B project. You can differentiate specific colors corresponding to different items. Also, it can avoid the trouble caused by pollution to your work.
Can I Reuse Headspace (GC) Vials?
As said before, disposable vials are expensive, wasteful, and pollute the environment. Therefore, after cleaning, many laboratories use the headspace vials. This is the most typical procedure for cleaning sample bottles in laboratories:
1. Adding washing powder
2. Adding the detergent
3. Adding the organic solvent
4. Adding the acid-base washing solutions
5. Then, you scrub the vial with a designed tiny test tube.
This traditional brushing approach has several flaws:
1. it uses a lot of soap and water.
2. takes a long time to wash.
3. and it’s easy to leave dead corners.
If you do use headspace vials, you have to be careful.
1. The used crimp cap will leak if the sample in the headspace produces an aerosol pressure. That may impair the accuracy of the test findings. Thus it is not suggested to repeat it.
2. If you fill a vial twice, the second injection’s peak area will be more extensive.
3. You can’t reuse the cap of the headspace vials since it is damaged when removed. The cushion (septa) of the vials, on the other hand, you may use only two or three times.
You may pull each vial’s sample only once. Otherwise, the sample will be incorrect, and the amount of sample will diminish.
Results of Using Re-Washed Vials and Closures
There is a lot of research conducted on this topic. Here are the results of just one of them:
Sample 1: Clear glass vials with re-washed 9 mm screw threads
Sample 2: Amber glass vials with re-washed 9 mm screw threads
Sample 3: New clear glass 9 mm vials (C4000-1W) with PTFE/silicone septa closures (C5000-54B)
Researchers tested these samples and came up with a conclusion.
So, is reusing the vials okay?
The comparison was between the new to the used vial. Here are the results:
• Scientists used GC and HPLC instruments to compare blank injections from re-washed vials.
• Extra components found in the GC-MS blanks in all cases. In the TIC mode, there was interference with standards.
• Due to an increased incidence of injection liner replacement, GC-Instrumentation downtime has risen.
• In HPLC, even minor volume injections resulted in the appearance of extra peaks in the UV mode.
• A complete mass range scan demonstrated the difference between tainted and new vials.
• When researchers used reused septa, the contamination of the injection was more considerable.
Most Asked Questions About HPLC Vials
Here are some of the most asked questions related to the cleaning and maintenance of the vials.
Is a vial sterile under the cap?
According to new findings, vial dust caps may not keep vial tops sterile. After “routine handling,” researchers collected samples of exposure to aerosolized E. coli or submersion in a bacterial solution. Also, researchers identified microbial contamination in two of the 12 vials in the regular handling group.
How do you sterilize vials for injections?
Sterilization is a crucial step in preventing bacterial development.
You can do it by:
1. heating the thing to a temperature high enough to kill germs,
2. irradiating it,
3. or using autoclaves.
You should use boiling water to sterilize glass vials.
How long is a single-use vial suitable for once punctured?
Unless the manufacturer’s label states otherwise, date and discard a single-dose vial within 28 days.
How do you sterilize a stopper?
The most frequent procedures for sterilizing rubber closures (e.g., stoppers):
1. Autoclaving (saturated steam),
2. gamma irradiation.
Both approaches can influence chemical and physical/functional qualities.
Conclusion
Using reused/re-washed vials and septa might jeopardize optimal chromatographic results. Reused vials and septa can make unpredictable peaks into otherwise repeatable chromatographic techniques.
This is a common cause of unexpected assay failures, after which you need to retest whole sample runs. Sometimes even from the very beginning.
Any benefits you may get from reusing the vials are not benefits. You spent time on retests and troubleshooting an assay failure that you can’t repeat.
Chromatographers that need uncompromised sample integrity should always use brand new vials and septa for each analysis.
