Ion Exchange (IEX)

Yes, the guard columns for Biozen are biocompatible. Though the holder is not titanium, the analyte flow path is biocompatible.

Chromatography is the separation of components in a mixture based on their chemical nature. Chromatography can be performed in either liquid (HPLC) or gas (GC) forms. Liquid chromatography, specifically High Pressure Liquid Chromatography (HPLC), involves a stationary phase (sorbent), a mobile phase (liquid) and the analyte or compounds of interest. Analytes or compounds of interest are injected onto an HPLC column (packed with sorbent that contains a variety of chemistries) in mobile phase. As the mobile phase, which is carrying the analyte or compounds of interest, travels across the stationary phase, the analyte or compounds of interest separate from each other as they interact with the stationary phase, each eluting from the column at various times. Gas chromatography (GC) is similar to HPLC in that is utilized with working analytes or compounds of interest that can be vaporized without decomposing. In GC, gas is used instead of a liquid (like in HPLC). As analytes or compounds of interest travel in the gas mobile phase and interact with the stationary phase, eluting at various times.

Luna NH2 (amino) columns are shipped in 99:1 hexane:acetonitrile. If the column is to be used in reversed phase or HILIC conditions, it is recommended to flush with IPA at low flow rate (10 column volumes) prior to introducing water:acetonitrile or water:methanol mixtures.

The reasons for noisy baseline with ELSD detectors are: • Evaporation temperature too low — the solvent is not completely evaporated • Evaporation temperature too high — the solvent is boiling in the nebulizer • Air or nitrogen not clean — remove traces of water or oil with a gas trap • Gas flow too low — poor nebulization of the eluent, increase the gas flow • Non-volatile material in the eluent — replace any buffer salt with a volatile one (such as ammonium acetate) and ensure that the eluent is particle free

For many anion exchange applications Luna NH2 will work well. Note that Luna NH2 columns are tested and shipped with hexane, so a solvent switch conditioning step is necessary prior to using for IEC.

A high concentration of water is necessary to ensure the sulfonate ligand is in an active ionized state. Furthermore, a high percentage of organic could cause irreversible swelling of the polymer backbone

RI detectors are sensitive to changes in flow rate, mobile phase composition and temperature. Ensure that the reference cell is full of the same mobile phase you are using for the method. Check that your pump is providing a stable flow rate. Finally, if your RI detector has its own temperature control, make sure that it is matched with the mobile phase temperature for the method. It is often advisable to have both the column and detector held at a higher temperature than ambient to ensure that a constant temperature can be maintained.

Both Rezex ROA and RHM columns are packed with the same stationary phase. However, the difference between the two columns is that ROA is QC tested under acidic conditions and the RHM is QC tested under neutral conditions. ROA is tested under acidic conditions as the intended analysis is for organic acids, which will be neutral under acidic conditions (e.g. 5mM H2SO4 Buffer)

PES (polyethersulfone) syringe filters show low non-specific binding for ionic species, this combined with their hydrophilic properties make them a good choice when the filtration of ionic species is required.