Nov. 20th, 2023
Chromatography is an increasingly popular technique in analytical chemistry that utilizes separation and analysis of complex mixtures. The success of chromatographic processes depends on various elements; one such component is the chromatography vial, which plays a significant role in maintaining sample integrity and producing accurate results. Here we explore all you need to know about materials used in these containers and ensure accurate results.
1. Glass Vials
Glass HPLC vials have long been a go-to choice in laboratories due to their exceptional chemical resistance and inertness. Borosilicate glass, one popular option, features an exceptionally low coefficient of expansion that makes it resilient against thermal shock - an attribute particularly helpful during sample preparation that involves temperature variations or analysis that relies on temperature data. Furthermore, borosilicate's stability ensures it won't introduce contaminants that interfere with separation processes like chromatographic separation; soda lime glass might also provide less resistance chemically than its counterpart.
2. Plastic Vials
Plastic chromatography vials have gained in popularity due to their cost-effectiveness, lightweight nature and disposability. Polypropylene and polyethylene plastics are popular choices when manufacturing vials for plastic chromatography applications; both may offer advantages when it comes to leaching protection of metal ions from solution, making them suitable for some applications; however they should be used with caution when used at elevated temperatures as some plastics may not withstand these temperatures.
3. Polytetrafluoroethylene (PTFE) Coating
PTFE coatings play an integral part in minimizing sample interactions with vial surfaces. Their non-stick properties reduce analyte adhesion onto vial walls, thus minimizing possible loss and assuring accurate quantification. This feature is particularly valuable when dealing with trace-level analyses where even minute amounts of analytes adsorption can have dramatic ramifications on results; hence PTFE-coated vials increase reliability and sensitivity during chromatographic measurements.
4. Silicone Septa
Septa, or caps, made of silicone are commonly found in chromatography vials due to its inert nature, flexibility and durability. Silicone provides a reliable seal that keeps out contamination while protecting samples against evaporation during an analytical process - both factors crucial in maintaining its integrity. Their elastic properties enable repeated usage while still securing an airtight seal, adding longevity to chromatography systems overall.
5. Vial Size and Shape
Chromatography vials come in various sizes and shapes to meet diverse analytical needs. Common sizes for routine analyses are 1.5 ml and 2 ml vials, though larger or smaller vials may be chosen depending on sample volume and specific analytical requirements. Vials that feature conical or flat bottomed bases have an impactful influence on sample evaporation rates as well as efficiency during separation processes - something researchers should take into consideration in order to optimize their workflow for maximum chromatographic separation results.
6. Certification and Quality Control
Certification of HPLC vials is a vital element in assuring their suitability for analytical use. Regulative bodies like the United States Pharmacopeia (USP) and European Pharmacopeia (EP) set stringent standards for materials used to make vials, adhering to these will guarantee vials meet specific quality criteria such as low extractables or interference with sample integrity, while stringent quality control measures during manufacturing ensure each vial complies with these standards - providing researchers with confidence in terms of reliable reproducible analytical results.
Within the complex world of chromatography, materials used in vial construction play an essential role in its success. Glass and plastic vials, PTFE coatings, and silicone septa each offer specific properties that enhance accuracy, sensitivity, and reliability during analyses. As researchers navigate their choices among them all, understanding these materials' properties and applications is key in selecting suitable vials - whether that be classic glass for time-tested reliability or modern plastic options - for use. Researchers can make informed decisions that have lasting results impactful results on their analytical endeavors.
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