Practical Aspects of Solvent Extraction
March 1st 2009Columnist Ron Majors discusses some of the practical considerations in the successful application of the popular yet age-old technique of solvent extraction (also known as liquid–liquid extraction, or LLE). After a brief review of the basics, guidelines on the selection of the appropriate extraction solvents and how to use acid–base equilibria to ensure efficient extractions of ionic and ionizable compounds are provided. Problems in LLE and the solutions to these problems are highlighted. A newer technique called dispersive liquid–liquid microextraction (DLLME) is introduced.
Optimizing Detector Set-up and Operating Conditions
March 1st 2009Detectors are another link in the chain of signals that a chromatographic analysis generates. After separation, a detector transduces the chemical signals of eluted analytes to an electrical signal that is then recorded and measured. The identities and amounts of analytes are determined from this information. This month in "GC Connections", John Hinshaw examines the environment, set-up and operating conditions necessary to ensure high gas chromatography detector performance and reliability.