Not many people are familiar with the term “chromatography.” But you may be surprised how much of an impact it has on your everyday life. It plays a role in food and drug testing, vaccine creation, and even fighting crime with forensics.
Chromatography uses precise equipment to know the composition of substances. It’s a potent tool used in all branches of science to separate compounds into their various components.
Understandably, chromatography relies heavily on instrumentation. One crucial part of the process is vial selection. Not using the correct autosampler vials can degrade the sample, yield inaccurate results, or even damage the equipment.
Read on to learn about the different factors to consider when choosing an autosampler vial for chromatography.
Compatibility
One of the most critical factors in the vial selection process is checking the autosampler for compatibility.
Autosamplers come in different models and may require a specific size or closure type. For example, some models use robotic arms while others use a rotating tray. Using the wrong vial could result in mechanical damage.
It’s best to consult the autosampler’s operating manual to determine the correct vial specifications.
Size
According to Chrom Tech, the 12x32mm vial has become the industry standard for most autosampler models. The 12x32mm vial can hold between 1.5 to 2ml of liquid.
Other standard vial sizes include 8x40mm and 15x40mm. Robotic arm autosamplers use a non-standard 9mm size.
Closure
Different closure options are available depending on the application and the autosampler model.
Screw thread vials are reusable and don’t require a special tool for removing or attaching the cap. Snap top vials are the most convenient for technicians since they can easily apply or remove the lid.
Crimp vials need a crimper and aren’t reusable, but they provide the best seal. Forensic labs also use crimp tops for tamper-proofing of samples.
Material
Plastic and glass are the two types of materials used to make vials.
Glass vials are valued for heat resistance and low reactivity. Type I Borosilicate glass is the least reactive glass, has minimal pH shift, and is the most common type of autosampler vial material.
Plastic vials are the more affordable option but can be incompatible with some substances like ethers and pentanes. Polypropylene is the best plastic material due to its good chemical resistance.
Color
The vial color is more important than you might think, although the color choices are limited to clear and amber. For most substances, clear vials would suffice. But for light-sensitive samples, you absolutely have to use amber or even black polypropylene vials.
Quality of Autosampler Vials
Chromatography and similar analytical methods like mass spectrometry require utmost precision. Everything must be high-quality, from sophisticated analytical equipment to simple vials.
Ensure that the vials you purchased, including the accessories such as the cap and septum, have a certification for quality. Check if the vials have an ISO 9001:2015 certification. It’s the international standard for a quality management system.
A Vial Is Not Just a Vial
Autosampler vials are often overlooked, but they serve a vital role in chromatography. Make sure that the vials are of the right size, closure, material, color, and compatibility. Any mistake with the specifications can mess up the analysis, or worse, your precious equipment.
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