Potentiometric and spectrophotometric determination of the dissociation constants of mesatone and epinephrine

Abstract

The dissociation constants of proton-acceptor and -donor groups of adrenaline (epinephrine) and mesatone were determined by potentiometric and spectrophotometric titration method. The potentiometric titration data were used to calculate the protonation constants of a secondary amino group in each drug, and the spectrophotometric titration data were used to determine the dissociation constants of OH groups influencing the distribution of electron density in the chromophore (aromatic system). Once the dissociation constants are known, the distributions of the ionized forms of epinephrine and mesatone at various ðH can be calculated. In these calculations, it is important to take into consideration the transport of biologically active molecules through membranes and their interactions with receptors.

Novel ultrasensitive and ultrafast voltammetric determination of biological aminochromes on the copper nanodoped mercury monolayer carbon fiber electrode

“…The dissociation constants (pK) of hydroxyl (catechol) groups of catecholamines are bigger than 9 [20] and at pH = 7.0 these groups are undissociated, thus hindering the complexation process with Cu 2+ . The different effect of o-BQ and p-BQ on the E oc suggests that the ortho configuration of the quinone radical is preferable for Cu 2+ complexation, which can explain the observed selectivity of o-quinone determination using tyrosinase [21], a copper-containing enzyme.…”

Label-Free Detection of Epinephrine Using Flower-like Biomimetic CuS Antioxidant Nanozymes

“…Therefore, developing a reliable sensitive assay to detect and determine trace levels of EP is very important in the medical allied aspect. Several standard methods have been developed already for the detection and determination of EP, such as chromatography, potentiometry, ICP–MS, electrochemical, and fluorescence methods, which have been used worldwide. − However, all the abovementioned methods need expensive instrumental facilities and dreary operation, which create a serious restriction upon their use in location-based on-time detection. Luckily, the colorimetric method has several advantages including easy operation techniques and low cost.…”