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Increasing LC–MS–MS Sensitivity with Luna HILIC
December 2nd 2007The analysis of polar compounds in support of clinical and pre-clinical pharmacokinetic studies requires an analytical methodology capable of achieving ultra-low detection and quantification limits. The high sensitivity afforded by coupling HPLC with tandem mass spectrometry (MS–MS) has made it the technique of choice in this environment, but it is subject to the following limitations when reversed phase liquid chromatography (RPLC) is used
Multi-Residue Pesticide Screening Method Using GC–MS
December 2nd 2007Pesticides are widely used by farmers to control pests, weeds and molds that would otherwise decrease crop production. While this has significantly increased worldwide food productions, these same pesticides pose health risks to humans. The restrictions for specific pesticides differ from one country to the next and as world trade increases, the potential threat to other countries' populations increases. For this reason, pesticides and other food related allergens are currently the subjects of increasing scrutiny and regulation.
Automated High-Throughput Formula Determination and Confirmation with "sub-ppm" Confidence
December 1st 2007Combining 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.
On-line SEC–Py-GC–MS for the Automated Comprehensive Characterization of Copolymers
December 1st 2007The pyrolysis fragments are first refocused on the top of the GC column, then separated and finally detected by the MS. At the end of the GC run the SEC flow is resumed again and the entire process is repeated.
A "Solid" Alternative for Analysing Oxygenated Hydrocarbons — Agilent's New Capillary GC PLOT Column
December 1st 2007PLOT columns are often used in GC analyses when it is necessary or desirable to retain one class of solutes in favour of other solutes that have little or limited interactions with the surface of the stationary phase. With a PLOT column, chromatographers can even cause lower boiling point compounds to elute well after higher boiling point compounds, thus providing better qualitative and quantitative separations for the solutes of interest.