ABSTRACT
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. Likewise, the alkyl chain length at the ammonium cation induces different biocidal efficacy and toxicology. Therefore, the object of this research was to develop a rapid and reliable method for the detection of ammonium cation and halide anion in a single analytical run. For that purpose, a gas chromatography mass spectrometry (GC/MS) method was developed for QACs of the dialkyldimethylammonium type. Pyrolytic conversion of the QACs in the injector port of the gas chromatograph into volatile molecule species allows fast and reliable subsequent GC/MS analysis. The developed method is suited for the determination of both the quaternary ammonium cation and the corresponding halide anion in a single gas chromatographic run. The application of this method to bulk material and standard material of explicitly specified didecyldimethylammonium chloride revealed deviations from the manufacturer's specifications in a range up to four-fifths. Furthermore, didecyldimethylammonium chloride was detected in a disinfectant that does not comply with the labeling requirement for biocidal ingredients. With the method presented, results can be obtained for disinfectants with minimum effort within seven minutes.
ABSTRACT
All-trans-retinoic acid (atRA) is the essential derivative of vitamin A and is of interest due to its various biological key functions. As shown in the recent literature, atRA also plays a role in the failing heart during myocardial infarction, the leading cause of death globally. To date insufficient mechanistic information has been available on related hypoxia-induced cell damage and reperfusion injuries. However, it has been demonstrated that a reduction in cellular atRA uptake abrogates hypoxia-mediated cell and tissue damage, which may offer a new route for intervention. Consequently, in this study, the effect of the novel cardio-protective compound 5-methoxyleoligin (5ML) on cellular atRA uptake was tested in human umbilical-vein endothelial cells (HUVECs). For this purpose, a high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) method was developed to assess intra-cellular levels of the active substance and corresponding levels of vitamin A and its derivatives, including potential cis/trans isomers. This work also focused on light-induced isomerization and the stability of biological sample material to ensure sample integrity and avoid biased conclusions. This study provides evidence of the inhibitory effect of 5ML on cellular atRA uptake, a promising step toward a novel therapy for myocardial infarction.