An efficient organo-catalyzed enantioselective addition of selenosulfonates to α,β-unsaturated ketones was developed for the first time.

(1) Background: Hydrogen sulfide (H₂S) is a widely recognized gasotransmitter, with key roles in physiological and pathological processes. The accurate quantification of H₂S and reactive sulfur species (RSS) may hold important implications for the diagnosis and prognosis of diseases. However, H₂S species quantification in biological matrices is still a challenge. Among the sulfide detection methods, monobromobimane (MBB) derivatization coupled with reversed phase high-performance liquid chromatography (RP-HPLC) is one of the most reported. However, it is characterized by a complex preparation and time-consuming process, which may alter the actual H₂S level; moreover, a quantitative validation has still not been described. (2) Methods: We developed and validated an improved analytical protocol for the MBB RP-HPLC method. MBB concentration, temperature and sample handling were optimized, and the calibration method was validated using leave-one-out cross-validation and tested in a clinical setting. (3) Results: The method shows high sensitivity and allows the quantification of H₂S species, with a limit of detection of 0.5 µM. Finally, it can be successfully applied in measurements of H₂S levels in the serum of patients subjected to inhalation with vapors rich in H₂S. (4) Conclusions: These data demonstrate that the proposed method is precise and reliable for measuring H₂S species in biological matrices and can be used to provide key insights into the etiopathogenesis of several diseases and sulfur-based treatments.

Dissolved oxygen (DO) is deeply involved in preserving the life of cellular tissues and human beings due to its key role in cellular metabolism: its alterations may reflect important pathophysiological conditions. DO levels are measured to identify pathological conditions, explain pathophysiological mechanisms, and monitor the efficacy of therapeutic approaches. This is particularly relevant when the measurements are performed in vivo but also in contexts where a variety of biological and synthetic media are used, such as ex vivo organ perfusion. A reliable measurement of medium oxygenation ensures a high-quality process. It is crucial to provide a high-accuracy, real-time method for DO quantification, which could be robust towards different medium compositions and temperatures. In fact, biological fluids and synthetic clinical fluids represent a challenging environment where DO interacts with various compounds and can change continuously and dynamically, and further precaution is needed to obtain reliable results. This study aims to present and discuss the main oxygen detection and quantification methods, focusing on the technical needs for their translation to clinical practice. Firstly, we resumed all the main methodologies and advancements concerning dissolved oxygen determination. After identifying the main groups of all the available techniques for DO sensing based on their mechanisms and applicability, we focused on transferring the most promising approaches to a clinical in vivo/ex vivo setting.