Application Notes: LC/HPLC

Sep 02, 2005
The Application Notebook
By LCGC Editors
XBridge? columns were designed to be the most pH stable phases commercially available, while still providing maximum efficiency, peak shape and robustness. For method development consideration, we offer C18, C8, phenyl and RP18 chemistries, available in 2.5, 3.5 and 5 ?m particle sizes and dimensions from analytical to prep. XBridge(?) Prep columns are manufactured with the patent-pending Optimum Bed Density (OBD?) design, which helps us to achieve direct scale-up from analytical to preparative columns, with the same efficiency and excellent column lifetimes.
Sep 02, 2005
The Application Notebook
By LCGC Editors
Polysaccharide-based CSPs are the media of choice for analytical and preparative chiral separations. Eurocel 01 employs microcrystalline cellulose tris(3,5-dimethyl-phenylcarbamate).
Sep 02, 2005
The Application Notebook
By LCGC Editors
The first factor is the sample itself. Crude, complex samples present more of a challenge for separation and maintenance of the integrity of a column. Any type of sample cleanup prior to analysis will not only provide a better separation but also extend the lifetime of the column.
Sep 02, 2005
The Application Notebook
By LCGC Editors
The use of ion-pairing agents in reversed-phase chromatography is quite common, and the effect of mobile phase composition on reversed-phase separations has been extensively studied in recent years.
Sep 02, 2005
The Application Notebook
By LCGC Editors
Ultra Performance Liquid Chromatography (UPLC?) enables chromatographers to meet the challenges of developing separations that completely characterize the constituents of samples by providing significant improvements in resolution, speed and sensitivity. These improvements are achieved through the use of columns with 1.7 ?m particle packings and a matching family of low dispersion, high speed instrumentation developed simultaneously to provide full compatibility between chemistry and instrumentation. Recently, additional bonded phases have been developed to focus on improving resolution by manipulating selectivity.
Sep 02, 2005
The Application Notebook
By LCGC Editors
The Acclaim? Polar Advantage II columns are high-efficiency, silica-based polar-embedded columns that incorporate an innovative, patent-pending bonding technology. These columns are fully compatible with 100% aqueous to 100% organic mobile phases and provide symmetrical peaks for polar and non-polar analytes.
Sep 02, 2005
The Application Notebook
By LCGC Editors
LC-MS is a powerful tool used for the characterization of proteins. Reversed-phase HPLC is the most common mode of chromatography coupled with mass spectrometry. This separation technique can also be an effective method for the desalting of proteins. Pharmaceutical biotherapeutics and other proteins are often prepared or stored in salt containing buffer solutions such as PBS (phosphate buffered saline). These buffer solutions contain salts that interface with ESI–MS analysis by suppressing ionization and by forming adducts. Therefore, separation of proteins from non-volatile salts is an important step prior to introduction into the mass spectrometer.
Mar 02, 2005
The Application Notebook
By LCGC Editors
Benzimidazoles, such as thiabendazole, are compounds that are commonly used as fungicides for protection of fruit and vegetable crops. The LC analysis of these substances can be challenging...
Mar 02, 2005
The Application Notebook
By LCGC Editors
The use of improved column technology, shorter columns packed with smaller particles, or elevated temperatures can increase sample throughput due to a higher separation efficiency and faster elution. The drawback is a fundamental change in methodology. The effort required to develop and validate a new method and create revised documentation often outweighs its benefits...
Mar 02, 2005
The Application Notebook
By LCGC Editors
SunFire™ C18 analytical and OBD™ preparative columns are designed to provide maximum loadability in simple mobile-phase conditions, accurate scalability and high peak capacity.
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