Browsing by Issue Date, starting with "2021-07-16"
Now showing 1 - 1 of 1
Results Per Page
Sort Options
- Investigation of possibilities for detection of stress hormones in Loggerhead sea turtles by MALDI TOF mass spectrometryPublication . Houdová, Dominika; Dellinger, Thomas; Petkovi´c, MarijanaLoggerhead sea turtles (Caretta caretta) are the most abundant and widespread sea turtle species in Madeiran waters. The species is considered endangered and is protected worldwide, as they encounter many stressors, whether nat ural or anthropogenic. Being high in the food chain they serve as effective indicator of marine ecosystem health. The most common method to evaluate the physiological stress is the mea surement of corticosterone (CS) levels in plasma. There are several analytical methods for determination of plasma corticosterone concentrations, however most of them require tedious and complicated procedures. The approach for detection and fast screening of CS in blood of a turtle tested in this work was simple, as MALDI does not require sample derivatization, which is extremely useful for analysis of low sample volumes. Since MALDI has limitations in analysis of small molecules, cholesterol was used as a model system for development of the method and as well nano materials (carbon dots (CDs), N-doped carbon dots (N-CDs) and graphene) were used in order to overcome signal suppression in presence of inorganic salts. It was found that CDs and N-CDs are sensitive to the cholesterol and can be used either alone or in a binary system with 2,5-dihydroxybenzoic acid (DHB) to improve detection. In the presence of NaCl, N-CDs had a better reproducibility of results. Afterwards, CS was subjected to analysis, the linearity, precision and limit of detection and quantification with three organic matrices were investigated. Signal-to-noise ratio of the CS-derived signal was used as parameter for quantification. In order to achieve better linearity and precision, isotopically labeled cor ticosterone was added at fixed concentration, as a correction factor. The signal at m/z 347.4 belonging to CS was clearly detected. The lowest mea sured concentration of CS extracted from plasma that was still detectable by MALDI-TOF MS was 0.04 mg/mL, which is approximately ten times higher than expected CS concentration in a turtles’ blood. The results of this work showed that this method has a potential for quantification of CS in turtles’ blood, however the sensitivity is low, and the method need further improvements.