Application Notes: LC

Jan 14, 2008
LCGC Asia Pacific
By LCGC Editors
HPLC Analysis of Triterpene Glycosides in Black Cohosh Formulations using the PL-ELS 2100
Dec 02, 2007
The Application Notebook
By LCGC Editors
Traditional HPLC methods use the so-called "analytical" columns, commonly 4.6 × 150 mm packed with 5 μm stationary phase, and run at 1.0–2.0 mL/min. New rapid separation LC (RSLC) columns yield equivalent performance in a shorter run time and consume less solvent, with existing instrumentation. Adapting a method to use 3 μm, 3.0 × 75 mm or shorter columns requires only the use of well-known geometric scaling rules, but the calculations are tedious and error-prone. We present a demonstration of the simplified process for adaptation of methods to RSLC.
Dec 02, 2007
The Application Notebook
By LCGC Editors
Simvastatin belongs to the group of cholesterol-lowering lactones known as statins which, in 2007, have been identified as being among the most widely prescribed drugs in the world. Statins lower cholesterol by inhibiting the synthesis of mevalonic acid, which is a key precursor in cholesterol synthesis. This application demonstrates how to transfer a method to high-speed LC, using the USP method for simvastatin as an example. A 100 mm Hypersil GOLD column containing 1.9 μm diameter particles will deliver the same efficiency as a 250 mm column containing 5 μm particles, in less time.
Dec 02, 2007
The Application Notebook
By LCGC Editors
Using ACQUITY UPLC technology with triple quadrupole MS detection enhances the selectivity, sensitivity and throughput in quantitative bioanalytical studies. Detection limits for these methods are being driven lower and lower as drugs become more potent. For this reason, methods with highest sensitivity possible must be developed. Additionally, this must happen under increasingly tight deadlines to shorten the drug development cycle. We have developed a straightforward, streamlined approach to efficient LC method development. This use of this approach is demonstrated in the generation of a sensitive and selective method for terfenadine and two of its metabolites, fexofenadine and azacyclonol. Fexofenadine, in particular, has gained importance as the commonly prescribed anti-allergic Allegra.
Dec 02, 2007
The Application Notebook
Combining an ultra fast LC system (e.g., Agilent 1200RRLC, Waters UPLC) with an accurate mass TOF mass spectrometer creates a powerful system for information-rich high-throughput analyses. However, for de novo formula generation and confirmation the residual mass accuracy tolerance of 3–5 ppm can still leave significant ambiguity in the proposed formula. Consequently, skilled manual inspection or further measurements deploying additional analytical techniques (NMR or MS–MS) are frequently required to arrive at a confident formula assignment.
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