Modern Techniques for the Extraction of Solid Materials — An Update
February 1st 2007Traditional methods for the sample preparation of insoluble solid materials have represented one of the more time consuming and labour-intensive efforts in analysis. In this instalment of "Sample Prep Perspectives", Ron Majors examines modern sample preparation methods for solids that often involve increased temperature and higher pressure to speed up the extraction process. In addition, modern sample preparation methods have been automated to relieve analysts of the drudgery associated with traditional methods. Here, he reports on automated Soxhlet extraction, supercritical fluid extraction, pressurized fluid extraction–accelerated solvent extraction, and microwave-assisted extraction and updates earlier coverage.
Facilitated Column Selection in Reversed-Phase Liquid Chromatography for Pharmaceutical Separations
This article gives an overview of the performance of a previously developed system for the ranking of C18 reversed-phase columns applied to different pharmaceutical analyses. The separation of eight different drug substances from their respective impurities was studied. The chromatographic procedure for acetylsalicylic acid, clindamycin hydrochloride, buflomedil hydrochloride, chloramphenicol sodium succinate, phenoxymethylpenicillin and nimesulide was performed according to the corresponding European Pharmacopoeia monograph. The separations of dihydrostreptomycin sulphate and vancomycin were performed according to literature. It was found that that the column ranking system is a helpful tool in the selection of suitable columns in these analyses.