Describe The Importance Of Sample Vial And Septa Quality
The importance of sample vial
If the tolerances are not strictly controlled, the market size and wall weight of the autosampler vial may be different, which will affect the sample volume in the vial. It is very important for a small number of samples. HAWACH’s strict tolerance control runs through the entire manufacturing process, from the initial design to the final photoelectric scanning inspection process to ensure the accuracy of each sample bottle and cap specifications. The integrity, cleanliness, and uniformity of the sample vials are critical to today’s demanding applications. All HAWACH sample vial comply with ISO9001 clean environment requirements The unique packaging guarantees cleanliness and safety during transportation.
The material of sample vial
Type I, 33-expanded borosilicate glass
It is currently the most chemically inert glass and is usually used in analytical laboratories to obtain high-quality experimental results. Its expansion coefficient is about 33×10 ^ (-7) ℃, mainly composed of silicon oxide, and also contains trace amounts of boron and sodium. All Waters clear glass sample bottles are Type I 33-expanded glass.
Type I, 51-expansion glass
All Waters brown glazed products are 51-expanded glass. Deactivated glass (DV) For analytes with strong polarity and binding to the polar glass surface of the glass, deactivated vials may be a good choice. The glass sample vial is treated with a glass-phase reactive organosilane to produce a hydrophobic glass surface. Deactivated vials can be stored dry indefinitely.
Polypropylene (PP) is a non-reactive plastic that can be used where glass is not suitable. Polypropylene sample vials can still maintain a good seal when fired, thereby minimizing the possibility of exposure to potentially hazardous substances. The maximum operating temperature is 135 ℃.
The importance of septa
To prevent contamination and prevent syringe and instrument damage, the correct septa selection is crucial. The following are some issues that you should pay attention to:
1. Temperature control
At higher temperatures, the septum will degrade and cause sample contamination. The rubber septum is only stable below 90℃, so it is not suitable for high-temperature applications. Generally, PTFE-lined silicone rubber septa are the best choice for various temperatures.
When the syringe diameter is too large relative to the septa or the septa material cannot withstand multiple injections, debris will be generated. At this time, the septa material will fall off into the sample vial and contaminate the sample. Here is how to prevent debris:
a. Choose PTFE-lined septa to prevent the septum material from entering the sample;
b. Make sure the syringe is not damaged, consider using a side hole syringe instead of a tapered syringe;
c. The use of pre-perforated septa can almost completely eliminate debris.
d. For highly sensitive samples, we recommend the use of PTFE lined (“sandwich”) septa, because the PTFE layer can act as a chemical-resistant barrier.
Resealability is an important factor to consider when choosing septa. PTFE / red rubber septa are not recommended for multiple injections or need to store samples for later analysis. When a long time is required between injections or any type of standard is added, PTFE / silicone rubber / PTFE is always the best choice.
The disadvantage of using poor quality vials and seals on the autosampler
The thickness of the bottom of the sample vial is inconsistent
Autosampler sequence stopped
Seal leak not detected
Septa that are not properly displaced or positioned
The inconsistent sample was taken; damaged injection syringe
Miss-taking or missing sample vials; loss of precious samples
Sample loss, volatilization; may contaminate the sample
Sample loss; sample contamination
Contamination of vial cap septa