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Propofol is a widely used intravenous anesthetic agent in sedation and general anesthesia. To improve the safety and maintain the depth of anesthesia, it is important to develop a rapid, sensitive, and reliable method to monitor the concentration of propofol in blood during anesthesia continuously. Here, we present a novel strategy based on paper spray ionization-mass spectrometry (PSI-MS) to detect propofol. Samples (in 10 μL) were mixed with methanol as protein precipitation solvent and 2,6-dimethylphenol as internal standard. Protein micro-precipitation was achieved with methanol by vortexing and centrifuging for 5 s each, and propofol was extracted to the supernatant. PSI-MS was performed in negative ionization mode, and MS signal lasted for 1 min. The analysis of a single sample was completed within 2 min. The area ratios of propofol to internal standard were calculated for quantification. Limit of detection of 5.5 ng mL−1 and limit of quantification of 18.2 ng mL−1 were achieved for propofol in whole blood. Calibration curve was linear in the range of 0.02–10 μg mL−1. The developed method was used successfully in monitoring the propofol concentration in 3 patients' whole blood during anesthesia, showing its further application in controlling and feeding-back target concentration infusion. [ABSTRACT FROM AUTHOR]

In various methods to determine alpha-emitting radionuclides in matrices, alpha-particle spectrometry with alpha-emitting sources prepared by the electrodeposition has been widely used. Although there are several good review papers on alpha-particle spectrometry and preparation of electrodeposited alpha-emitting sources, the mechanism of analysis procedure and characterizations of alpha-emitting sources have not been reported well. These untouched subjects by other review papers are very significant to improve the analysis procedure. This review focuses on the mechanism of the electrodeposition of alpha-emitting radionuclides on the stainless steel disc, factors for the preparation of electrodeposited alpha-emitting layers, and various characterization methods. [ABSTRACT FROM AUTHOR]

An outlook on the current status and trends in desorption electrospray ionization-mass spectrometry (DESI-MS), one of the most common spray-based techniques for ambient ionization, is given with a focus on the main advances recently achieved or still in progress regarding studies of surface properties affecting the signal stability and efficiency of the DESI process. Future directions that the field may take in the years to come are discussed, with particular focus on bioanalytical research. [ABSTRACT FROM AUTHOR]

Luciferin molecules are common luminophores found throughout the biological kingdoms. Here, electrospray ionization and tandem ion mobility spectrometry coupled with laser spectroscopy are used to demonstrate that D-luciferin and oxyluciferin deprotonated anions can be produced in two isomeric forms, which can be separated by virtue of their different collision cross sections with a buffer gas. The two isomers possess distinguishable but partially overlapping photodepletion action spectra over the visible range, implying distinct intrinsic absorption profiles. The site of deprotonation and tautomeric forms of the electrosprayed isomers are assigned through comparisons between experimental and calculated collision cross sections and electronic excitation energies. The study clearly shows that electrospray ionization of biochromophore molecules can generate multiple isomeric forms with distinct electronic spectra. [ABSTRACT FROM AUTHOR]