Biomedical subjects

Sarah M R Wille

Publications and source records attributed to Sarah M R Wille.

4 recordsLinked to original sources

PubMed2006

Traces of phosgene in chloroform: consequences for extraction of anthracyclines.

Chloroform is commonly used to extract anthracyclines from various biological matrices. However, their determination can be seriously compromised by phosgene traces present as a result of failing stabilization of chloroform. Out of the three varieties in which chloroform exists (not stabilized, stabilized with an alcohol and stabilized with a hydrocarbon) only the ethanol stabilized type minimizes chances on creating artifacts. Chromatographic separation after extraction of four anthracyclines (doxorubicin, epirubicin, daunorubicin and idarubicin) and two metabolites (13-S-dihydrodoxorubicin and 13-S-dihydroepirubicin) with chloroform under various conditions indicate that the appropriate choice of stabilizer in this extraction solvent is highly relevant.

Amines↗

PubMed2005

Development of a solid phase extraction for 13 'new' generation antidepressants and their active metabolites for gas chromatographic-mass spectrometric analysis.

A solid phase extraction procedure (SPE) for 13 'new' antidepressants (venlafaxine, fluoxetine, viloxazine, fluvoxamine, mianserin, mirtazapine, melitracen, reboxetine, citalopram, maprotiline, sertraline, paroxetine and trazodone) together with eight of their metabolites (O-desmethylvenlafaxine, norfluoxetine, desmethylmianserine, desmethylmirtazapine, desmethylcitalopram, didesmethylcitalopram, desmethylsertraline and m-chlorophenylpiperazine) from plasma is optimized using HPLC-DAD as monitoring system. Special attention has been paid to the choice of washing and eluting solvent, resulting in a highly concentrated, clean and moisture free extract, also suitable for GC-MS. A total number of 10 sorbents (apolar, polymeric, ion-exchange and mixed mode) was evaluated. Based on recovery, reproducibility and absence of interfering substances the strong cation exchanger gave the best results. Recoveries were determined at low and high therapeutic and toxic levels and ranged between 70 and 109% for all compounds, except for trazodone (39%).

Antidepressive Agents, Second-Generation↗

PubMed2004

Phenmetrazine or ephedrine? Fooled by library search.

Chemical and/or thermal conversion of analytes in a sample and/or GC injector can mislead the identification of analytes in a toxicological screening. In addition, library search can even more complicate the identification. The risk for false positive identification of phenmetrazine in an ephedrine-containing sample analysed by GC-MS is described. Ephedrine reacted with formaldehyde contamination in solvents to a compound with a similar mass spectrum as phenmetrazine. High injection temperatures influenced the formation speed.

Chromatography, Gas↗

PubMed2004

Volatile substance abuse--post-mortem diagnosis.

A substantial number of children and adolescents world-wide abuse volatile substances with the intention to experience an euphoric state of consciousness. Although the ratio of deaths to nonfatal inhalation escapades is low, it is an important and preventable cause of death in young people. In the analytical investigation of volatile substances proper sample collection, storage and handling are important in view of the volatile nature of the compounds. Volatile organic compounds in post-mortem matrices such as blood, urine and tissues are generally determined by gas chromatography after extracting the compounds with methods such as static and dynamic headspace or even with pulse-heating and solvent extraction. In post-mortem cases, metabolites in urine seem less relevant, however, trichloroethanol and trichloroacetic acid were determined in several cases. When interpreting qualitative and quantitative results, researchers should be aware of false conclusions. The main reason why scepticism is necessary is the occurrence of losses of analytes during sampling, sample handling and storage, which results in false quantitation.

Administration, Inhalation↗