Extraction of artemisinin and artemisinic acid from Artemisia annua L. using supercritical carbon dioxide.

Artemisinin (an antimalaric compound) and its major precursor artemisinic acid, isolated as the active principles of the medicinal plant Artemisia annua L., were extracted by supercritical fluid extraction (SFE) and analyzed by supercritical fluid chromatography (SFC) using a capillary column, coupled with a flame ionization detector (FID). With optimized operating conditions, artemisinin and artemisinic acid were quantitatively extracted at a flow-rate of 2 ml min-1 in less than 20 min.

Subcritical fluid extraction of opiates in hair of drug addicts.

Hair analysis is a useful complement to blood and urine analysis in forensic science, but current procedures are tedious and time consuming. Owing to the difficulty of having a sufficient amount of hair in order to perform the optimization of the extraction method, standard hair was made and the procedure is described. The spiking method is reproducible and linearity can be obtained.

Determination of divalent trace metals in natural waters by preconcentration on N,N,N',N'-tetra(2-aminoethyl)ethylenediamine-silica followed by on-line ion chromatography.

A method for the on-line preconcentration and chromatography of trace metals, e.g., Co, Ni, Cu, Zn, Cd and Pb, on N,N,N',N'-tetra(2-aminoethyl)ethylenediamine-bonded silica is described.

Cadmium speciation studies in the intestine of Lumbricus terrestris by electrophoresis of metal proteins complexes.

Cadmium speciation of the intestinal compartment of the earthworm species, Lumbricus terrestris, has been investigated using polyacrylamide gel electrophoresis under non-denaturing conditions. Worms exposed to Cd(NO3)2 supplemented soils have been studied and compared to control samples. Prior to electrophoresis, the worm intestines were removed and dissected.

Enrichment of complexing analytes on a copper-loaded silica surface and on-line coupling with high-performance liquid chromatography, using L-tryptophan and L-tyrosine as model compounds.

A chemically modified silica (bisdithiocarbamate) strongly binds copper and has a loading capacity of 0.5 mmol g-1 for the copper ion. This new metal-loaded silica, packed in a short stainless-steel pre-column, is highly selective for the enrichment of two amino acids chosen as model compounds.