How To Choose The Right Small Sample Vial Septa?

Compared with the many precision analytical instruments used in the laboratory, the sample vial seems irrelevant, but the wrong use of the small sample vials for sale, cap, and septa will have a significant impact on the experimental results, resulting in reduced experimental efficiency and repeatability, affecting the experimental data. In serious cases, it will cause irreparable damage to the experimental instrument. Today, HAWACH will mainly discuss how to choose the right sample vial septa.

PTFE/natural red rubber
PTFE natural red rubber septa of 2 ml HPLC sample vials are moderately priced and have good chemical properties, suitable for GC and HPLC. Sealing performance is good after repeated use, and it is an ideal choice for multiple injections, but the penetration performance is worse than PTFE/RR.

PTFE/Red synthetic rubber septa: (PTFE/RR)
PTFE/red rubber septa are popular and economical choices for general GC and HPLC applications. PTFE/red rubber septa have moderate repeatability and excellent chemical inertness before penetration. They are mainly used for routine gas chromatography analysis using FID, TCD and FPD detectors.

The red rubber has low hardness and can be easily penetrated by the needle, even with a fine needle of gas chromatography. It is not recommended to use PTFE/red rubber septa for multiple injections or to retain samples for further analysis.

PTFE/silicone septa: (T/S)
PTFE/silicone septa features high quality, low background noise/blank value, 100% synthetic pure silica septa, suitable for all types of chromatography applications. The thickness of the PTFE layer is compressed to 0.005″, with high purity, high inertness, excellent resealing performance, and can withstand multiple punctures.

The PTFE/silicone septa is an ideal choice for most HPLC and GC applications and can meet its repeated sealing and purity requirements, which is cleaner than natural rubber or red rubber. There are a variety of different hardness options to meet the requirements of different types of needles.
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Pre-opened PTFE/silicone septa
The high-purity silica gel layer of PTFE/silica septa is pressed with a 0.005″ PTFE layer in the center hole to facilitate needle penetration and release vacuum when a large number of samples are drawn. The chromatographic characteristics are similar to those of non-pre-open septa, and are resistant to corrosive solvents. The ability to use is slightly weaker.

PTFE/silicone/PTFE septa: (T/S/T)
The septum is a high-purity, medium-hard silica gel with a 0.003″ thick PTFE layer pressed on both sides to avoid slag loss while still maintaining good resealing performance. T/S/T septa are recommended for two injections important applications such as long interval time or the use of internal standard methods, such as trace analysis. T/S/T septa have excellent performance and are suitable for autosamplers using large diameter blunt needles.

PTFE septa
With solid 0.010″ thick PTFE layer and excellent chemical inertness, the PTFE septa can withstand strong corrosive solvents. The film facilitates the penetration of most needles. The PTFE septum is not re-sealable and must be used for analysis of short injection intervals or single injections.

Grey butyl rubber septa
The grey butyl rubber septa is an economical choice for lower temperature (125°C) or low pressure applications. The gray butyl stopper does not have a PTFE layer and is not suitable for use in alkanes, benzene, chlorinated solvents, or cyclohexane.

Gray PTFE/Red rubber septa
It has the characteristics of good solvent resistance, resealability and resistance to dross. It is an economical choice when PTFE layer is needed.

PTFE/white silicone septa
It is ideal for volatile samples. The septa are packed in glass jars to ensure low background noise, low permeability and other properties, and meet all the requirements of headspace sampling. PTFE/silicone septa have excellent resealing characteristics and extensive chemical compatibility.

Gray PTFE/Black butyl septa (Pharmafix type)
It is a molded septum with a PTFE liner on the center surface, but does not extend to the edge of the septum. The central area of PTFE is well tolerated by many solvents. The central puncture area has anti-slag properties and can be sealed again after multiple punctures. The black butyl outer sealing edge is tightly seamed with the 2 ml sample vials mouth, and the sealing effect is better.

Thermal stability table
Material Lowest temperature °C Highest temperature °C
PTFE/red natural rubber -10 85
PTFE/Red synthetic rubber septa: (PTFE/RR) -30 110
PTFE/silicone septa: (T/S) -60 200
PTFE/silicone/PTFE septa: (T/S/T) -60 200
Polyethylene (PE) -50 80
Polypropylene (PP) 0 121
Butyl/chlorinated butyl/bromobutyl rubber stopper or septum -20 125
Gray PTFE/Black butyl septa (Pharmafix) -20 125
Black rubber septa -20 120

HAWACH offers a complete range of sample vials, from general-purpose sample vials to certified sample vials for analysis of very low concentrations, which can meet any of your sample needs. HAWACH small sample vials are manufactured to specific strict tolerances and are guaranteed to be suitable for various brands of automatic chromatography instruments.

They are made of durable Type I borosilicate glass with low metal content, which can protect your samples from unstable damage or contamination by leaching materials. HAWACH sample vials are designed for high pressure strength during heating, thereby reducing the possibility of cracking.