Aug 15, 2020 · Most gas supplies used should fall between 99.995% - 99.9995% purity range and contain a low levels (< 0.5 ppm) of oxygen and total hydrocarbons in the tank. The carrier gas system contains a molecular sieve to remove water and other impurities.

May 29, 2017 · Gas chromatography coupled with mass spectrometry (GC-MS) is still the “gold standard” for chemical identification of volatile organic compounds in mixtures. It offers consistency and reproducibility with a wide range of established methodology ranging from clinical and pharmaceutical analysis, to environmental and forensic applications.

To prevent GC septum coring, don’t overtighten the septum nut, be sure to routinely replace your septum, and inspect your syringe (manual or autosampler) for tip damage. Also, consider switching to a softer, more pliable septum. Softer septa are less likely to core than firmer septa. Remember, however, that softer septa usually have a lower

Jun 8, 2019 · In 1955-56, Dow Chemical scientists Fred McLafferty and Roland Gohlke first demonstrated the combination of gas chromatography (GC) and mass spectrometry (MS) to identify individual substances in a mixture. This was the first coupling of a separation technology with a spectrometry technique to provide rapid characterization of chemical components.

Inlet Septa for Gas Chromatography. Advanced Green inlet septa eliminate sticking and reduce coring. Bleed temperature optimized (BTO) inlet septa are preconditioned and ready to use with low-bleed, mass spec capillary columns. Our long-life septa are specially formed for extended use, meaning less downtime. Explore Aijiren's complete portfolio

The septa material, dark red or gray in color, is specified to withstand over 200 automatic injections at an injection port temperature of 350 °C. You can have confidence in your chromatographic results knowing that each lot of septa goes through a demanding QC test to ensure that only the highest quality product is delivered to your laboratory.

Sep 1, 2005 · Figure 2 - Septum degradation (seen as ghost peaks). Following is a simple test that can be performed in the laboratory: Keep the column cold (30 °C) for 15 min, perform a blank run (no injection—only a temperature program up to 300 °C), and observe the baseline. After that run, cool the column to 30 °C again, keep it at 30 °C for 60 min

PTFE septa are not resealable and should not be used with highly volatile solvents, short cycle times or multiple injection methods. PTFE septa are rarely used for GC applications. Polyethylene (PE) septa and integral molded closures Chemically resistant polyethylene septa are molded into single-piece caps.

Use Lined Septa. Most vial cap septa are lined with a protective layer of polytetrafluoroethylene (PTFE) to prevent solvent attack. As shown in Figure 3, PTFE effectively prevents septum breakdown due to solvent exposure. In comparison, unlined vial cap septa exhibit bleed after just 24 hours at room temperature.

(SCD). Another common GC detector is the mass spectrometer. Mass spectrometry (MS) is a technique that is used to elucidate molecular mass and molecular structure for compound identification and/or quantification. While MS can be done without GC separation, interpretation of the data becomes increasingly more difficult when analyzing mixtures.

Jul 10, 2012 · Different septa shown in Figures 2A–2D used in this study were obtained from various sources, including: SGE Analytical Science (Australia, part number 041904; suggested application maximum temperature of 400°C); yellow PTFE coated (part number 041827 suggested application maximum temperature of 200°C); Aijiren Tech BTO (part number THC31303230 no suggestion of application maximum temperature) supplied with the GC–MS instrument system; and CNW Technology (Germany), ultra-low bleed

Apr 18, 2012 · LC-MS in Drug Metabolism and Pharmacokinetics: A Pharmaceutical Industry Perspective (Pages: 119-169) Wenying Jian, Wilson Shou, Richard W. Edom, Naidong Weng, Mingshe Zhu Summary PDF References Request permissions CHAPTER 7 Quantitative Mass Spectrometry in Support of Pharmacokinetic Studies (Pages: 171-189) Xiaoying Xu, Wenkui Li Summary PDF

Apr 23, 2018 · A Beginner’s Guide: How to Interpret Gas Chromatography Mass Spectrometry Results. Gas chromatography mass spectrometry (GC/MS) analysis is an effective testing and troubleshooting tool for many manufacturers across industries, helping identify and quantify the materials that make up a sample or uncover contaminants that impact product

Jan 1, 2012 · In the current paper, 14 different brands of magnetic caps with silicone–polytetrafluoroethylene (PTFE), butyl–PTFE, or butyl rubber septa were tested. The total emission of septa over a 4 h period was also evaluated. The tested septa emitted 39 different compounds, which are mainly hydrocarbons, alcohols, and ketones.

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