LCGC Asia Pacific-09-01-2007

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.

How can you reduce mobile phase expenses?

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.

This feature highlights some of the current analytical research being undertaken across China by focusing on the work of several research groups at academic institutions.

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.

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.

This article describes the development of a routine method to analyse epoxidized soybean oil (ESBO) in baby food...

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...