Simultaneous analysis of quaternary ammonium cations and corresponding halide counterions by pyrolysis gas chromatography / mass spectrometry.

The use of quaternary ammonium compounds (QACs) as disinfectants has increased tremendously in the COVID-10 pandemic to inactivate Severe Acute Respiratory Syndrome Coronavirus type 2 (SARS-CoV2). Dialkyldimethylammonium halides represent a frequently used type among QACs. Different halide anions, each ionically linked to the same quaternary ammonium cation, show clear differences in biocidal activity, toxicity and allergic potential.

Discrepancies in the German Pharmacopoeia procedure for quality control of Quillaja saponin extracts.

This study focused on the evaluation of Quillaja saponin extracts with the additional quality designation DAB-which means the abbreviation of the German Pharmacopoeia (Deutsches Arzneibuch). This label suggests that Quillaja saponin extracts marked in this way are of pharmacopoeial quality and thus stand out from other Quillaja saponin extracts. The DAB ninth edition listed Quillaia saponin as a reagent.

Collision cross sections obtained with ion mobility mass spectrometry as new descriptor to predict blood-brain barrier permeation by drugs.

Evaluating the ability of a drug to permeate the blood-brain barrier is not a trivial task due to the structural complexity of the central nervous system. Nevertheless, it is of immense importance to identify related properties of the drugs either to be able to produce a desired effect in the brain or to avoid unwanted side effects there. In the past, multiple methods have been used for that purpose.

Identification of thymol phase I metabolites in human urine by headspace sorptive extraction combined with thermal desorption and gas chromatography mass spectrometry.

Development of a novel highly sensitive headspace sorptive extraction (HSSE) method in combination with thermal desorption gas chromatography coupled to a mass spectrometer (TD-GC/MS) allowed the identification of thymol and several phase I metabolites in human urine. Combined with an enzymatic hydrolysis of glucuronated or sulphated phase II metabolites of thymol and of the respective phase I metabolites prior to analysis, even trace quantities of hitherto not detected thymol phase I metabolites could be identified in urine samples of test persons after oral administration of 50mg thymol. It was proven, that human metabolism leads to a hydroxylation of the aromatic ring as well as of the iso-propyl side chain.