LCGC Asia Pacific-09-01-2007

LCGC Asia Pacific

Routine Switching between High and Low pH on Xbridge HPLC Columns

September 01, 2007

Application Notes

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The effect of switching between high and low pH mobile phases on a single analytical HPLC column was investigated. The ability to rapidly switch between pH extremes on XBridge columns without special washing/re-equilibration steps dramatically reduces the time for separation of pharmaceutical compounds.

Solvent Conservation

September 01, 2007

LC Troubleshooting

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How can you reduce mobile phase expenses?

A Novel Method for the High-Speed Determination of Fuel Diluents in Lubricating Oils

September 01, 2007

Application Notes

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The performance of lubricating oil is significantly degraded by the presence of fuel contaminants such as gasoline and diesel. Recycled oil is particularly susceptible to this form of contamination. Consequently, producers and distributors of lubricating oil must go to great lengths to ensure the levels of fuel contamination are kept to a safe limit (typically 4–5%) in these products.

Rapid Compound Identification from Crude Oil Enabled by Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

September 01, 2007

Application Notes

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The analysis of crude oil by means of different atmospheric pressure ionization (API) techniques is described. Crude oil is analysed without any separation prior to API-Fourier transform mass spectrometry. The use of a quadrupole/hexapole device to selectively enhance a certain mass range is demonstrated. Automated generation of molecular formulas from accurate mass measurements enables rapid compound identification.

On-Line and Off-Line Application of Micro-SPE (MEPS)

September 01, 2007

Application Notes

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Solid-phase extraction (SPE) has revolutionized sample preparation. Variations on the technique offer enhanced recovery, greater speciation and reduced solvent and sample consumption over other techniques. Micro-extraction packed sorbent (MEPS) is the miniaturization of conventional SPE from millilitre to microlitre bed volumes that allows SPE to be used with very small samples. The manipulation of the small volumes is achieved with a precision gas tight syringe. With a typical void volume of 7 μL, the volume of solvent eluted from MEPS is compatible with GC and LC inlets making it ideal for integration into an automated sampling system for on-line SPE.

Advanced Topics in Solid-Phase Extraction: Chemistries

September 01, 2007

Sample Preparation Perspectives

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In this instalment of "Sample Preparation Perspectives", columnist Ron Majors discusses advanced topics such as multimodal SPE, restricted-access media, molecular imprinted polymers, immunoaffinity extraction phases and other class-or compound-specific sorbents...