I. A. Revel’skii

Bio: I. A. Revel’skii is an academic researcher from Moscow State University. The author has contributed to research in topics: Mass spectrum & Supercritical fluid extraction. The author has an hindex of 5, co-authored 23 publications receiving 75 citations.

Determination of organic compounds in human hair

Abstract: Data reported in the literature on methods for the determination of organic compounds of different classes in human hair are systematized. Special attention is given to methods for the extraction and preconcentration of organic compounds from hair. A comparative analysis of existing methods is performed.

Determination of organic impurities in pharmaceutical preparations

Abstract: Data reported in the literature on methods for the determination of organic impurities in pharmaceutical preparations are systematized; the characteristics and possibilities of the methods are compared.

DART mass spectrometry: rapid analysis of soft medicinal formulations

Abstract: The possibility of using the DART mass spectrometry method for rapid analysis of soft medicinal formulations is considered. Studies of “tetracycline”, “Sintomycin Liniment”, and “Levomecol” creams and suppositories based on hard fat were studied. The possibility of using this method for the rapid screening of medicinal formulations in search of counterfeits is discussed. This is the first report of the analysis of suppositories using DART mass spectrometry.

Atmospheric Pressure Photoionization Mass Spectrometry: New Capabilities for the Determination of the Numbers of Components in Complex Mixtures and Their Identification

Abstract: The atmospheric pressure photoionization and photochemical ionization mass spectrometry (APPI/APPCI−MS) makes it possible to compare the number of peaks in a mass spectrum with the number of components in the test mixture because of the measurements of the mass spectra of individual compounds, which mainly consist of the peaks of a molecular ion (M+) or a protonated molecule (MH+). The capabilities of gas chromatography–electron ionization (EI) and atmospheric pressure ionization mass spectrometry for the identification of trace components of complex mixtures are considered. The advantages of APPI/APPCI−MS, which makes it possible to increase the reliability of the detection of components in the complex mixtures of organic compounds, over EI mass spectrometry are shown. The work was performed at the Department of Analytical Chemistry, Faculty of Chemistry, Moscow State University.

Mass Spectrometry: Recent Advances in Direct Open Air Surface Sampling/Ionization

Abstract: 1. Scope of this Review 2270 2. Ambient Ionization Techniques 2272 2.1. Solid−Liquid Extraction-Based Techniques 2272 2.1.1. Desorption Electrospray Ionization (DESI) 2272 2.1.2. Desorption Ionization by Charge Exchange (DICE) 2277 2.1.3. Easy Ambient Sonic-Spray Ionization (EASI) 2278 2.1.4. Liquid Micro Junction Surface Sampling Probe (LMJ-SSP) 2279 2.1.5. Liquid Extraction Surface Analysis (LESA) 2279 2.1.6. Nanospray Desorption Electrospray Ionization (nanoDESI) 2280 2.1.7. Desorption Atmospheric Pressure Photoionization (DAPPI) 2280 2.2. Plasma-Based Techniques 2281 2.2.1. Direct Analysis in Real Time (DART) 2282 2.2.2. Flowing Atmospheric-Pressure Afterglow (FAPA) 2286 2.2.3. Low Temperature Plasma (LTP) & Dielectric Barrier Discharge Ionization (DBDI) 2286 2.2.4. Chemical Sputtering/Ionization Techniques 2287 2.3. Two-Step Thermal/Mechanical Desorption/ Ablation (Non-Laser) Techniques 2288 2.3.1. Neutral Desorption Extractive Electrospray Ionization (ND-EESI) 2288 2.3.2. Beta Electron-Assisted Direct Chemical Ionization (BADCI) 2288 2.3.3. Atmospheric Pressure Thermal Desorption-Secondary Ionization (AP-TD/SI) 2289 2.3.4. Probe Electrospray Ionization (PESI) 2289 2.4. Two-Step Laser-Based Desorption Ablation Techniques 2290 2.4.1. Laser-Based Hybrid Techniques Coupled to ESI or Plasma Ionization 2290 2.4.2. Laser Electrospray Mass Spectrometry (LEMS) 2292 2.4.3. Laser Ablation Atmospheric Pressure Photoionization (LAAPPI) 2293 2.4.4. Laser Ablation Sample Transfer 2293 2.5. Acoustic Desorption Techniques 2294 2.5.1. Laser-Induced Acoustic Desorption (LIAD) 2294 2.5.2. Radiofrequency Acoustic Desorption Ionization (RADIO) 2295 2.5.3. Surface Acoustic Wave-Based Techniques 2295 2.6. Multimode Techniques 2296 2.6.1. Desorption Electrospray/Metastable-Induced Ionization (DEMI) 2296 2.7. Other Techniques 2296 2.7.1. Rapid Evaporative Ionization Mass Spectrometry (REIMS) 2296 2.7.2. Laser Desorption Ionization (LDI) 2297 2.7.3. Switched Ferroelectric Plasma Ionizer (SwiFerr) 2297 2.7.4. Laserspray Ionization (LSI) 2297 3. Remote Sampling 2298 3.1. Nonproximate Ambient MS 2298 3.2. Fundamentals of Neutral/Ion Transport 2298 3.3. Transport of Neutrals 2298 3.4. Transport of Ions 2299 4. Future Directions 2300 Author Information 2300 Corresponding Author 2300 Author Contributions 2300 Notes 2300 Biographies 2300 Acknowledgments 2301 References 2301

Identification of Pharmaceutical Impurities

Abstract: Identification of pharmaceutical impurities is a critical analytical activity in the drug development process whose goal is to fully elucidate the chemical structures of unknown pharmaceutical impurities present in either drug substances or drug products above a particular threshold. Knowledge of the chemical structure of an impurity is essential to assess its toxicological implications and to gain an understanding of its formation mechanism. Knowledge of the formation mechanism is critical for improving the synthetic chemical processes and optimizing the drug formulation to reduce or eliminate the impurity. This article reviews the current regulatory requirements for impurity identification and the chemical origins of various impurities, particularly those derived from degradation of drugs. Strategies for identification of pharmaceutical impurities are discussed followed by an overview of the critical steps and the roles of various analytical techniques, such as HPLC‐DAD, LC‐MS, LC‐NMR, GC‐MS, a...

Tomographic filtering of geodynamic models: Implications for model interpretation and large‐scale mantle structure

Abstract: [1] The resolution operator R is a critical accompaniment to tomographic models of the mantle. R facilitates the comparison between conceptual three-dimensional velocity models and tomographic models because it can filter these theoretical models to the spatial resolution of the tomographic model. We compute R for the tomographic model S20RTS (Ritsema et al., 1999, 2004) and two companion models that are based on the same data but derived with different norm damping values. The three models explain (within measurement uncertainty) S-SKS and S-SKKS travel times equally well. To demonstrate how artifacts distort tomographic images and complicate model interpretation, we apply R to (1) a thermochemical and (2) an isochemical model of convection in the mantle that feature different patterns of shear velocity heterogeneity in the deep mantle if we assume that shear velocity heterogeneity is caused by temperature variations only. R suppresses short-wavelength structures, removes strong velocity gradients, and introduces artificial stretching and tilting of velocity anomalies. Temperature anomalies in the thermochemical model resemble the spatial extent of low seismic velocity anomalies and the shear velocity spectrum in the D’’ region better than the isochemical model. However, the thermochemical model overpredicts the amplitude of shear velocity variation and places the African and Pacific anomalies imperfectly. We suspect that inaccurate velocity scaling laws and uncertain initial conditions control these mismatches. Extensive hypothesis testing is required to identify successful models.