Rapid determination and continuous monitoring of propofol in microliter whole blood sample during anesthesia by paper spray ionization-mass spectrometry

Dynamic headspace solid-phase extraction at room temperature: a theoretical model, method, and application for propofol analysis

Herein, a simple dynamic headspace solid-phase extraction (DHS-SPE) process at room temperature was used for a material that is sensitive to increase in the temperature. A proposed method was implemented to rapidly extract propofol (PF) from a complex matrix before fluorescence spectroscopy analysis, within a short sampling time without involving a hot plate or stirrer. A mini diaphragm pump was used to circulate the headspace gas. As the headspace gas flows over the sample solution surface, bubbles form and release analytes from the liquid into the headspace. During the extraction process, the headspace gas passes through the coated metal foam as a sorbent that is placed in a homemade glass vessel and analytes are trapped from the gas phase. A theoretical model of DHS-SPE based on the consecutive first-order process is proposed in this study. A mathematical solution for the dynamic process of mass transfer was obtained by correlating the variation in analyte concentration in the headspace and adsorber with the pump speed and amount of analyte extracted to the solid phase. Using electrochemically Nafion-doped polypyrrole (PPy-Naf) film on nickel foam as the solid-phase coupled to fluorescence detection, a linear dynamic range over the concentration range of 100-500 nM with a detection limit of 15 nM was obtained. This method was applied successfully for PF determination in human serum sample matrices without the interference of co-administered drugs, such as cisatracurium, which have significant emission spectrum overlap. The developed method can lead to a new idea for sample pretreatment, which is compatible with many analytical techniques and has been successfully combined with fluorescence spectroscopy in this work. This format of sampling simplifies the transfer of analytes from complex matrices to the headspace for the extraction and preconcentration process, eliminating the heating step and the need for expensive equipment.

Potential of desorption electrospray ionization and paper spray ionization with high-resolution mass spectrometry for the screening of sports doping agents in urine

In this work, desorption electrospray ionization and paper spray ionization both with high-resolution mass spectrometry (DESI-HRMS and PSI-HRMS) were explored for the fast and direct analysis of stimulants and diuretics in urine samples. The analysis was performed at a resolution of 70 000 FWHM (m/z 200) using a quadrupole-Orbitrap mass spectrometer in full scan acquisition mode, detecting stimulants and diuretics in positive and negative ion modes, respectively. The most critical parameters affecting the desorption and ionization efficiencies of compounds were optimized, paying particular attention to the optimization of the spray solvent for PSI-HRMS analysis and to the selection of the DESI sample substrate. For stimulants, the PSI-HRMS method performed better than DESI-HRMS, allowing the direct analysis of raw urine samples with better signal-to-noise ratios than DESI. However, results obtained for diuretics were not as satisfactory as we expected. The PSI-HRMS method was applied to the screening of 52 stimulants for doping control purposes, providing satisfactory detectability for most of them at the Minimum Reporting Level (MRL) in less than 2 minutes for each single analysis. Despite the advantages offered by the PSI-HRMS method, in this study is also included a discussion on the limitations observed because of the presence of interference for some compounds.

Development and validation of a paper spray mass spectrometry method for the rapid quantitation of remdesivir and its active metabolite, GS-441524, in human plasma

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Rapid PS-MS/MS quantification of remdesivir and its active metabolite, GS-441524, directly from plasma.

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No sample preparation, short turn-around time, use of stable isotope-labeled internal standards.

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Robust stability data are presented.

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Suitable for adjusting remdesivir dosage for optimal efficacy and minimal toxicity.

Introduction

Remdesivir (GS-5734) is a nucleoside analog prodrug with antiviral activity against several single-stranded RNA viruses, including the novel severe respiratory distress syndrome virus 2 (SARS-CoV-2). It is currently the only FDA-approved antiviral agent for the treatment of individuals with COVID-19 caused by SARS-CoV-2. However, remdesivir pharmacokinetics/pharmacodynamics (PK/PD) and toxicity data in humans are extremely limited. It is imperative that precise analytical methods for the quantification of remdesivir and its active metabolite, GS-441524, are developed for use in further studies. We report, herein, the first validated anti-viral paper spray-mass spectrometry (PS-MS/MS) assay for the quantification of remdesivir and GS-441524 in human plasma. We seek to highlight the utility of PS-MS/MS technology and automation advancements for its potential future use in clinical research and the clinical laboratory setting.

Methods

Calibration curves for remdesivir and GS-441524 were created utilizing seven plasma-based calibrants of varying concentrations and two isotopic internal standards of set concentrations. Four plasma-based quality controls were prepared in a similar fashion to the calibrants and utilized for validation. No sample preparation was needed. Briefly, plasma samples were spotted on a paper substrate contained within pre-manufactured plastic cassette plates, and the spots were dried for 1 h. The samples were then analyzed directly for 1.2 min utilizing PS-MS/MS. All experiments were performed on a Thermo Scientific Altis triple quadrupole mass spectrometer utilizing automated technology.

Results

The calibration ranges were 20 – 5000 and 100 – 25000 ng/mL for remdesivir and GS-441524, respectively. The calibration curves for the two antiviral agents showed excellent linearity (average R² = 0.99–1.00). The inter- and intra-day precision (%CV) across validation runs at four QC levels for both analytes was less than 11.2% and accuracy (%bias) was within ± 15%. Plasma calibrant stability was assessed and degradation for the 4 °C and room temperature samples were seen beginning at Day 7. The plasma calibrants were stable at −20 °C. No interference, matrix effects, or carryover was discovered during the validation process.

Conclusions

PS-MS/MS represents a useful methodology for rapidly quantifying remdesivir and GS-441524, which may be useful for clinical PK/PD, therapeutic drug monitoring (TDM), and toxicity assessment, particularly during the current COVID-19 pandemic and future viral outbreaks.

Applications of ambient ionization mass spectrometry in 2021: An annual review

Ambient ionization mass spectrometry (AIMS) has revolutionized the field of analytical chemistry, enabling the rapid, direct analysis of samples in their native state. Since the inception of AIMS almost 20 years ago, the analytical community has driven the further development of this suite of techniques, motivated by the plentiful advantages offered in addition to traditional mass spectrometry. Workflows can be simplified through the elimination of sample preparation, analysis times can be significantly reduced and analysis remote from the traditional laboratory space has become a real possibility. As such, the interest in AIMS has rapidly spread through analytical communities worldwide, and AIMS techniques are increasingly being integrated with standard laboratory operations. This annual review covers applications of AIMS techniques throughout 2021, with a specific focus on AIMS applications in a number of key fields of research including disease diagnostics, forensics and security, food safety testing and environmental sciences. While some new techniques are introduced, the focus in AIMS research is increasingly shifting from the development of novel techniques toward efforts to improve existing AIMS techniques, particularly in terms of reproducibility, quantification and ease-of-use.

Design of Two-Mode Spectroscopic Sensor for Biomedical Applications: Analysis and Measurement of Relative Intensity Noise through Control Mechanism

The design of an intracavity spectroscopy based two-mode biomedical sensor involves a thorough investigation of the system. For this purpose, the individual components that are present in the system must be examined. This work describes the principle of two very important gadgets, namely the Fibre Bragg Grating (FBG), and the tunable coupler. We adhere to a Petri network scheme to model and analyze the performance of the FBG, and the results mirror strikingly low difference in the values of Bragg Wavelength during its ascending and descending operational principle, thereby maintaining the accuracy of the sensor’s results. Next, a pseudocode is developed and implemented for the investigation of the optical coupler in LabView. The values of its maximum output power are determined, and the coupling ratio for various values of controlling voltage is determined at three different wavelengths. The hysteresis results mirror an extremely low difference between the forward and reverse values in the results. Both the results of the FBG and the coupler are thereby extremely reliable to use them in the laser system, as evident from the respective intensity noise outcomes, as well as the experimentation on substances of interest (Dichloro Methane and Propofol).

An Overview of Analytical Methods for the Estimation of Propofol in Pharmaceutical Formulations, Biological Matrices, and Hair Marker

Propofol (PFL) owing to its excellent inhibitory property of neurotransmitters in CNS by positive modulation of ligand gated ion channels to an integrated chloride channeled GABA_A thereby acts as a general anesthetic. It differs from other general anesthetics chemically and pharmacologically as it has lesser side effects compared to other general anesthetics and is most commonly used. The present review focuses on two aspects (a) various analytical methods used in quantification of Propofol in pharmaceutical formulations and (b) various analytical methods used to determine Propofol in biological matrices and some biological markers like hair and end tidal nasal air for forensic purpose to estimate drug concentration in suspected cases. Here the various analytical methods are developed using different parameters and validation of employed methods are discussed. Estimated parameters like the linearity, LOQ (Limit of quantification), % recovery, slope, intercept, validation are discussed for the individual method. The critical quality attributes like the wavelength of detection, columns, flow rate, gas flow, and the sample preparation methods for the determination of PFL by bioanalytical methods are also discussed. Type of electrode, mechanism involved and the potential voltage applied for a particular electrochemical method are also discussed.