The applied septum is crucial for optimal analysis. Primarily, the septum should be inert to the sample solution and at the same time protect it from outside contamination as well as from possible evaporation. Almost all sealing discs are coated on one side with PTFE (Polytetrafluoroethylene), which has a high chemical resistance and forms an inert barrier between the sample and the carrier material of the septum. The carrier materials have different physical and chemical properties, e.g. temperature resistance, reclosing properties, purity, hardness, thickness, etc. We offer bottle septa with a diameter of 8mm to 22mm. Select the needed size in the drop down menu on the left. Choose from septa by Agilent Technologies and our home brand Altmann Analytik. These septa are a low cost and high quality alternative.
Properties and applications of septa made of TEF, PTFE, butyl, silicone etc.
• Standard quality for HPLC • Good reclosure properties for multiple injections • Relatively inexpensive • Temperature resistant from -40 ° C to 120 ° C • Not very clean as a natural product • Punching discs (punched from sheet / roll material
RedRubber / PTFE (synthetic rubber)
• NEW standard quality for HPLC and GC • Synthetic rubber, cleaner and softer than natural rubber • Relatively inexpensive • Temperature resistant from -40 ° C to 110 ° C • Punching discs (punched from sheet / roll material)
Butyl (septa / stopper)
• In the absence of a PTFE coating, only for uncritical analyzes • Butyl as a synthetic rubber cleaner than natural rubber • Very cheap as there is no PTFE coating • Application examples: breweries, blood alcohol analyzes • Original Butyl stopper for PerkinElmer • Forming discs (vulcanized and formed in a mold)
Pharma-Fix Septum Butyl / PTFE
• Specialty: Pharma-Fix washer only centric PTFE-coated butyl disc; The elastic butyl lying on the glass edge achieves a significantly better seal than the slippery surface of a completely laminated sealing disc • Butyl as a synthetic rubber cleaner than natural rubber • Relatively inexpensive compared to silicone • Temperature resistant from -40 ° C to 120 ° C • Synthetic rubber has poorer reclosure properties than natural rubber • Forming discs (vulcanized and formed in a mold)
(PTFE /) silicone / PTFE
• Silicone is the purest synthetic elastomer and is therefore used for critical analyzes • Temperature resistant from -60 ° C to 200 ° C • Improved reclosure properties than NK / TEF as a synthetic elastomer • (segmented) septa in HPLC as penetration aids for thick / blunt needles and for producing a valve effect in the case of multiple injections • Specialty: PTFE-coated silicone washers on both sides for low particle formation • punching discs (punched from sheet / roll material)
Silicon / aluminum foil
• All chemical and physical properties, such as silicone / PTFE • However, slightly higher temperature resistance from -60 ° C to 220 ° C • Frequently on PerkinElmer devices • More expensive than PTFE-coated septa
Pure PTFE septa
• Very inert, therefore also as a coating on most other sealing discs • No elastomer -> No sealing -> No reclosing properties • Do not press-fit into caps; Are therefore often only sold unassembled • Very cheap • Only for very uncritical applications • Are often used on VWR (Merck) / Hitachi and Waters instruments
Durometer (hardness of the septum)
Durometer is the hardness of a septum, expressed in ° shore. The higher the "shore" number, the harder the septum, the lower the "shore" number, the softer the septum. The softest sealing disc is 45 ° shore A and the hardest 70 ° shore A is hard. In addition to the thickness of the disc, the hardness is an important indicator, which septum is suitable for the penetration of a certain needles (sensitive needles, thin or thick needles, pointed or blunt needles, etc.).