Feb 16, 2009 · I learnt from the septa makers that hexane should not be in contact with the septa, but as some of you noted, this is practically impossible if each vial is sampled several times. We have decided to discard septa after a day of work or so, and that seems to do the trick. Also frequent dry runs with the gas mixture help in eliminating phantom peaks.

PTFE/silicone septa are always best. What force is required to penetrate the septum? Generally, silicone septa are more easily pierced than red rubber or butyl septa. For thicker, hard-to-pierce septa, a small gauge (23 gauge) needle may be required, or a stronger S-needle can be used. Preslit septa are the best option for

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Best septa choice when temperatures are over 125°C. Natural PTFE/red silicone – ST3HT High temperature formulated seal with low bleed. Best septa choice when temperatures are up to 300°C. Blue silicone/red PTFE – ST144 Thin 1.4 mm seal with PTFE face. Resealing capability limited due to thinner silicone layer. Aluminum/white silicone – AS3

When preparing mobile phase, always use chem ically clean and particle-free solvents and reagents. Solvents must be prefiltered by the manufacturer with a 0.2-µm (or smaller) filter. Based on current analysis, Aijiren Technology recommends using the following solvent brands (or their equivalents): • J.T.Baker®: LC/MS Grade

make PTFE/silicone septa suitable for all types of chromatographic applications. A thin film of PTFE is laminated to the side of the septum that faces the sample to limit exposure of the elastomer to the solvent. PTFE/Silicone septa are ideal for use in most HPLC and GC applications where resealability and purity are critical.

Best septa choice when temperatures are up to 300°C. Blue silicone/red PTFE – ST144 Thin 1.4 mm seal with PTFE face. Resealing capability limited due to thinner silicone layer. Aluminium/white silicone – AS3 Reflective aluminium face protects the silicone seal. The white silicone is suitable for use up to 170°C. Aluminium/red silicone – ASH3

septum material from standard septa will ulti-mately bleed into the injection port, creating ghost peaks and a surface that is even more prone to septa sticking (Figure 4). The nonstick plasma treatment also effectively eliminates surface contaminants that can cause Figure 4. Residues from standard septa inside injection port.

Septa are available with two or even three layers of material. PTFE / Silicone septa (T/S) are the most useful for HPLC applications as they have wide chemical compatibility and low

Chemically resistant polyethylene septa are usually molded into single-piece caps. The surface for needle penetration is 0.01" thick, allowing for use with most HPLC autosamplers. Polyethylene septa are not resealable and are intended for single injection use with aqueous based sample mixtures. Polypropylene (PP) Septa and Integral Molded Closures

PTFE/Silicone Septa: (T/S) High quality, pure silicone is laminated to 0.005” thick PTFE to give a pure, highly inert septum with excellent resealing characteristics even after repeated punctures. PTFE/Silicone septa are the preferred product for use in most HPLC and GC applications where resealability and high purity are critical.

Dec 16, 2022 · SYMPTOMS: Contaminant ions observed in LC-MS runs that use preslit PTFE or silicone septa vial caps Contaminant ions are observed when doing replicate injections; the first injection is clean Contaminant ions observed in LC-MS runs that use preslit PTFE or silicone septa vial caps - WKB12032 - Aijiren Technology

• Self-sealing septa contain silicone that can interfere with LC/MS applications. • Single-layered septa are acceptable if they do not contain plastics or adhesives that can contaminate the sample manager (PTFE is recommended). 3. Use Aijiren Technology‐brand wellplates. Other brands can leach plasticizers (for example, diisooctyl

Recently we have observed that few times the sample when injected from a particual vial is giving different area than the same solution when refilled in a different vial. The 1st vial repeatedly gives the same area even on changing the cap & septa, injection by removing both caps & septa, injection by removing only septa.