If you’re performing chemical research, developing new products, or seeking to find new cures for common diseases, you’ll likely experiment without countless different compounds and chemicals.
One of the most important methods for analyzing chemicals is chromatography. Chromatography is the process of separating compounds into individual components.
And one of the most effective forms of this is gas chromatography (GC. which is used in many industries. including healthcare and even forensic science. It’s often used to estimate when an individual last consumed alcohol, which is useful after crimes or car accidents.
But to perform GC right, you need to select a GC vial that is designed for your particular experiment.
GC vials come in many different materials, shapes, and sizes and are not one size fits all. Keep reading below to learn how to select the right GC vials and closures for your lab.
- Choose a GC Vial that Fits Your Machine
Your number one consideration is to choose GC headspace vials that fit into your machine. Most labs that perform gas chromatography use a machine called an autosampler.
But even these aren’t one size fits all, as there are many manufacturers producing dozens, if not hundreds of different models. Each machine might fit a different size vial.
So first and foremost, check the manufacturer’s requirements when it comes to vial size and shape.
The required size and shape need to be very precise, as robotic arms need to be able to pick up the vials with ease and place them into various trays. They need to be in the perfect position for the sampling needle to enter the vial as necessary.
Having the wrong type of vial in your machine can lead to damage and spills, which can be expensive to remediate.
Many machines use standard vial sizes, such as 8 x 40mm, 12 x 32mm, and 15 x 45mm. But some variations, including those with robotic arms, often use non-standard sizes like 9 mm, just to make it confusing for you. - Vial Material
Most CG vials are made of either glass or plastic. Both materials have their merits, though one is much more common in serious laboratories.
Higher-end labs prefer glass most of the time. Since glass is a pure material, and is heat resistant, it’s better suited to the rigors of chromatography. And it has less of a chance of impacting the results.
However, glass is heavier and costlier. And occasionally, you may run into substances that stick to glass.
In these instances, plastic vials may be a better option. Since plastic is a lot cheaper, you’ll often find these in training labs, where they are likely to be broken frequently.
Most labs will likely have both types of GC vial caps and vials. The use of different materials will depend on the particular chemicals used. - Vial Size
You can find GC vials that carry 1 ml, 2 ml, or 4 ml of working samples. Most machines are capable of servicing all of these vials, so long as the overall dimensions are fitted to the requirements of the machine, as mentioned earlier.
If performing experiments by hand, smaller vials can lead to a lot more human error, since adding small amounts of chemicals can be difficult. That’s why autosamplers are typically used for gas chromatography since they can be much more precise when working with samples as small as 1 ml.
The benefit of using smaller vials, when feasible, is less waste. Certain chemicals can be very costly, so working with 1 or 2 ml samples is a big benefit. - Vial Closures
GC vials only work well when fitted with the right closures. Closures need to be secure, so as to prevent spills which could be dangerous.
Manufacturers like Chrom Tech focus on producing crimp top closures since they are the most common for use with autosamplers. Crimp tops are fitted with seals for tight, permanent closure and no risk of leaks. But they are harder to open and close.
Choose snap-on closures when you need to frequently open and close the bottles.
Some vials are designed in a way that accepts both crimp and snap-on closures, allowing you to adjust depending on the particular experiment conducted.
Screw-on closures are also available in a number of sizes, for when an easy, less-secure method of storing is necessary.
Along with the fitting type, closures come in a wide range of colors. Varying colors are actually very useful in a busy laboratory setting, as color coordination allows for easier organization. - Light Sensitive Samples
Many compounds and chemicals are sensitive to light. The use of clear glass or plastic wouldn’t stop UV rays from reaching the compounds and could lead to sample deterioration or false results.
For these compounds, the use of amber-colored vials is recommended. Amber vials absorb UV light and prevent it from reaching the contents of the vial. So they can be stored in a bright lab without fear of deterioration.
Of course, you can choose solid-colored vials, which block out light completely. But clear, amber vials allow you to see how much liquid is present in the bottle without having to open it up and expose it to oxygen.
- Accessories for GC Vials
Once you purchase your Chrom Tech or Agilent GC vials, you might need some additional tools and accessories to go along with them.
GC vial inserts are available for a variety of different use cases. Conical inserts are available to help eliminate dead volume within each vial, helping you to maximize space. They can also absorb the shock of needle inserts, making for. safer experiment.
Flat-bottom inserts are also available and can be fitted to your specific vial size.
You can also get a CG vial rack (or five) to help you store and organize samples. Whether you are storing empty bottles that are ready to use or samples that need time to sit, racks make it easy to keep vials secure and out of the way. - Buying the Right Vials
Any lab that conducts gas chromatography likely has hundreds of vials available. But purchasing a new GC vial shouldn’t be rushed. If you buy right, your experiments will be easier to manage, and the results will be more accurate.
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