Choosing septa for polar solvents in HPLC

Oct 13, 2016 · Maintaining your LC columns. Proper storage of HPLC columns will increase longevity and performance. For long-term storage, it is best to follow manufacturer’s recommendations. Waters recommends storing used columns in 100% acetonitrile and avoiding long-term storage in buffered eluents. If the column was used with buffered mobile phase, it

withstand exposure to aggressive solvents is slightly lessened. Pre-slit septa are highly recommended improving injection to injection reproducibility with autosamplers withdrawing greater than 50µL of sample from a 2mL vial. Polyethylene (PE) Septa: Polyethylene septa are offered as single piece caps where the septum is molded as a part of

tions employed a polar support particle and a non-polar eluent. In a typical RP-HPLC separation, these are reversed. The support particle is non-polar; either a resin or carbon particle or a silica particle which has been bonded with a non-polar molecule such as alkyl chains or phenyl rings. Common RP-HPLC eluents are polar solvents such as

d. Use the smallest solvent reservoir appropriate for your analysis (it will depend on your flow rate and the length of your runs). e. Do not top off solvents. Instead, discard old solvent, rinse the bottles and solvent inlet filters with the solvent that will be used, and then refill with fresh solvent. Finally, do a wet prime.

Nov 5, 2018 · A: Evaporation of both solvent and analytes can occur over time, even with re-sealing septa like PTFE/Silicon. It is very much dependent on the chemistry of the analytes, the diluent, and the

3.2: High Performance Liquid chromatography. High-performance liquid chromatography (HPLC) is a technique in analytical chemistry used to separate the components in a mixture, and to identify and quantify each component. It was initially discovered as an analytical technique in the early twentieth century and was first used to separate colored

Mar 31, 2022 · First, let’s find out what septa is in short terms: Septa is a circular silicone or silica gel gasket. You can put septa in the cap of the HPLC Vial to seal the vial. Also, with that action, you guarantee that there is no gap between the cap and the vial in the HPLC analysis.

Choosing a Mobile Phase–Using the Polarity Index. There are several indices that help in choosing a mobile phase, one of which is the polarity index. 12 Table 12.4 provides values of the polarity index, P′, for several common mobile phases, where larger values of P′ correspond to more polar solvents. Mixing together two or more mobile

Sep 20, 2017 · Sample Solvent Strength. Maximum Injection Volume. 100% Strong Solvent. Stronger than mobile Phase. Mobile Phase. Weaker than Mobile Phase. ≤ 10 µL. ≤ 25 µL. ≤ 15% of Peak Volume.

PTFE/Silicone septa are ideal for use in most HPLC and GC applications where resealability and purity are critical. Pre-slit PTFE/Silicone Septa Pre-slit septa are offered in many of the same formulations as for non-slit PTFE/silicone septa and shares most of the physical and chemical characteristics.

Non-polar such as C18 or phenyl. Mixture of water and polar organic solvent. Accounts for a majority of HPLC separations. Normal Phase (NP) Polar such as unbound silica. Mixture of less-polar organic solvents. Water-insoluble samples and isomers. Hydrophilic Interaction (HILIC) Polar such as silica or amide-bonded phase

Choosing the correct septum material is vital, as it will interact with the analyte in your sample matrix as well as the sampler needle. Choose a material that is as inert as possible to your sample analyte and makeup solvents. Table 1 shows the range of septum materials and their corresponding compatibilities to a

Match the deactivation of the fused silica tubing with the polarity of the injection solvent. In most cases, it is also recommended to match the I.D. of the capillary column. Table 5 lists I.D. and O.D. information for our analytical and guard columns. Choose: Non-polar deactivation for injection solvents such as alkanes, carbon disulfide, and

Non-polar Mid-polar Polar Highly polar Volatile Non-volatile Light-stable Light-sensitive Glass vials SureSTART Performance level 1, 2 and 3 *GOLD-grade glass SureSTART Performance level 3 *Silanised glass vials **Polypropylene (PP) vials GOLD-grade glass vials and inserts When low levels of inorganic are required and for solvent stability

Reversed phase HPLC (RP-HPLC) has a non-polar stationary phase and an aqueous, moderately polar mobile phase. One common stationary phase is a silica which has been surface-modified with RMe 2 SiCl, where R is a straight chain alkyl group such as C 18 H 37 or C 8 H 17 .