The sample vial may be small, but the knowledge is great. When problems arise in HPLC test results, the sample vial is always the last thing checked. But, it should be the first. When choosing the right sample vial, consider three things: the septa, the caps, and the vial. This article will start with the vial's material. It will introduce you to the materials used in detail. It will help you choose the vial that suits you.

Scientists use different materials in HPLC. There are two main ones for making sample vials: glass and plastic.

The most common sample vial in HPLC testing is glass vial. Common glass vials are available in two colors: amber and clear. Two materials make up the two color sample vials. One is type I 33-expanded borosilicate glass, and the other is type I 51-expanded glass. Type I 33-expanded borosilicate glass is the most inert glass available. It is ideal for analytical labs to get high-quality results. Silicon oxygen compose it and it also contains trace amounts of boron and sodium. You need to consider that its expansion coefficient is about 33x10^(-7) ℃. The vials are transparent samples.

Wondering what to consider when choosing an HPLC autosampler vial? Check out this article detailing: 5 Points Need to Consider When Choosing An Autosampler Vial

Glass sample vials are available in two colors: clear and brown.

Brown vials made of Type I 33-expanded borosilicate glass. This is the most used vial in chromatographic testing. Type I 51-expanded glass is more alkaline than Type I 33-expanded borosilicate glass. Many lab purposes can use it. Its expansion coefficient is about 51x 10^(-7) ℃. Silicon and oxygen make it up, along with small amounts of boron. Brown sample vials consist of Type I 51-expanded glass. Brown sample vials are better for storing photosensitive samples than transparent ones. They are also better for storing all samples.

Besides those two, deactivated glass (DV) is also a common sample vial material. The preparation of deactivated glass requires special processes. It is suitable for various sample types. These include: organic compounds, biological samples, drugs, and environmental samples, and so on. For polar analytes that can bind to the polar glass surface, deactivation glass is a good choice. Analysts need to have strong polarity. Treating glass sample vials with glass-phase reactive organosilane creates a hydrophobic glass surface. You can store deactivated vials dry.

Plastic material

Polypropylene plastic (PP) is non-reactive. It can be used in experiments where glass vials are not an option.

Looking to learn everything about plastic HPLC/GC vials? Check out this article: 2ml Polypropylene Autosampler Vials for HPLC & GC Introduction.

Glass vs Plastic

Plastic vials are cheaper in the lab. They help you save money. But for special experiments, glass vials can only withstand moderate heating. Too much heat may break the vial. It can also bend the glass and let out harmful substances. It might even harm experimenters. It will also react with the sample. This will change the sample's stability and the analysis accuracy. For this reason, it is imperative to keep glass sample vials away from high temperatures. So, PP sample bottles cut exposure to dangerous materials. They can be used up to 135°C while still sealing well during a fire.

Glass sample vials are inert at room temperature, while some samples may react with plastics. Glass is a fragile product. If you think about it in the long term, you need to consider that it will wear, break, and even cause injuries to experimenters. You don’t need to worry about this with plastic vials.

Clear glass sample vials provide excellent transparency for easy observation of samples. PP material cannot achieve the transparency of clear glass.

Glass vials have more types of bottle necks. You can choose from threaded necks, bayonet tops, and crimp tops. But, plastic vials only have threaded necks and bayonet tops.

You can print written marks on glass vials, which makes it easier to separate and manage glass vials. Plastic vials cannot be printed with written marks. But, the scale lines can be printed on them. And, the written marks will not wear out from long-term use.

Wondering why glass chromatography vials are better than plastic vials? Check out this article detailing: Top 3 Reasons Why Glass Chromatography Vials are Better Than Plastic Vials.

At present, glass vials are the first choice for most laboratories for chromatography experiments.

You should take into account the characteristics of the sample, the cost of the experiment, your personal preferences, and the experimental apparatus while choosing vials. If you have any questions about the best vial for your test, please contact our online customer care team. They will be happy to help.

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