Sample Vials Through the Ages

Often looked at as a commodity, a sample vial has a high impact on the quality of the results and operational efficiency for methods used by scientists. In this article, I highlight the history of vial certification and how a modern, state-of-the-art certification process can increase the productivity of labs while lowering cost.

The dark ages of sample vials

Certified vials have been around for the better part of 20 years. Some of you may remember the olden days when it was an adventure to choose the right vial for an application. Autosamplers, or sample managers of the day used different vial formats, depending on the manufacturer. Glass vials were produced by artisans who didn’t have a solid insight into the need of usage of lab environment. Packaged to enable long-distance shipping and prevent breakage and without consideration of the impact of potential contamination from packaging material, the dimensions of the vial varied by-category.

Throughout the 1700’s and 1800’s, septa materials (the dividing wall between the substance and the vial), were chosen by price only and the general manufacturing quality of available product reflected that. There was no real established standard, and only manufacturer-specific spec sheets from which one had to extrapolate the suitability for the application at hand. Random contaminant peaks were not uncommon within a sample run. However, longer sample runs were interrupted due to either mechanical interaction of the needle with the vial or a plugged needle caused by removing the central part of non-suitable septa. This was an unacceptable situation for chemists. Autosampler and high-performance liquid chromatography (HPLC) system manufacturers felt the wrath of dissatisfied lab managers, calling support lines for help and asking field service engineers to fix plugged systems. These were events which cost both parties time and money at the additional expense of customer satisfaction.

The age of enlightenment

Improvements in column technology and the resulting increase in separation and sensitivity, brought demands for higher quality of results. Enter: Certified Vials. Certified Vials were dimensionally and chemically tested to reduce system errors and ensure a clean product. The promise of liquid chromatography/gas chromatography (LC/GC) Certified Vials was simple: reliable operation in all autosamplers, and reduction of random contaminations into the sample from either glass or septa. To achieve this, several aspects had to be addressed:

• Glass dimensions and cleanliness
• Septa consistency and cleanliness
• Packaging material cleanliness
• Test procedures ensuring that the above criteria are met

As we get into the late 1990’s and early 2000’s, the critical, mechanical measurements were identified, and it was a matter of adjusting manufacturing parameters to ensure glass vials adhere to the correlating dimensions. Residues, such as oils and grease present in any manufacturing environment, needed to be removed from the glass so no organic residue remains in the finished sample vial. Improvements in the septa manufacturing process were developed to prevent introduction of manufacturing agents. The removal of the use of adhesives, through bonding the septa into the cap, eliminated the use of non-required compounds. Typical packaging materials during this time introduced many contaminants, warranting new and clean packaging. To ensure the whole package including glass vial, cap, and septa performed to customers’ expectations, a certification test was developed. The evaluation includes:

• Dimensional test of glass, executed during glass manufacturing
• Septa cleanliness test with GC, executed during septa manufacturing
• Chemical HPLC test of the packaged product, looking at typical contaminants from packaging and manufacturing processes

Thus, the LC/GC Certified Vial for HPLC was born. The world rejoiced! Autosamplers and sample vials lived happily ever after.

Snake oil

The impact on customer success, increased operational reliability, cost reduction, and the success of a good product on the market, did not go unnoticed for too long. Today there is a slew of “Certified Vials” available for purchase on behalf of many companies, all promising better performance at a lower price point. But in many cases, “certification” remains unclear. The certifications may only indicate that the vial is lot-controlled, or that it is packaged in a clean room, or, that the vials are manufactured following quality management standards. Very often this “certification” is only about the sample vial dimensions, but the cap and septa must be purchased separately – which are not certified.  A closer look at the offered certified vials environment reveals that there are very few certified vial, cap and septa packages which are tested with HPLC for cleanliness on the market. For that reason, higher tiers of “certification” have been introduced which deliver to this basic promise – but at a higher price point, removing the cost advantage. Be wary of snake oil. And read the fine print of the “certification” promise.

The modern age

Sample vials for high performance liquid chromatography (HPLC) are an integral part of the liquid chromatography (LC) workflow in the analytical lab. To meet the demand of modern HPLC analysis, Waters had a critical look at our LC/GC Certified Vials and the certification process. We found that an improvement to the existing chemical certification test would be beneficial for our customers and for every routine QC lab that relies on high throughput operations.  

Today, we still test and certify the whole vial, cap, and septa in package after it spends 10 days in its’ packaging, to ensure the cleanliness of the whole kit. Additionally, we test the vial, cap and septa when packaged during manufacturing. Looking at the whole vial kit reflects more accurately how vials are received and used in a variety of labs. The LC method has been upgraded to a new UHPLC gradient separation using one of our UPLC™ Columns. We measure the level of impurities against a set of standards at a very low UV wavelength of 195nm. Passing this stringent test ensures that the sample vial, cap and septum are free of contaminant peaks during routine analysis.

Read in depth about the work behind the upgrade in Waters vial packages.

Have a look at the updated line of Waters Certified Vials

Additional Resources:

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