Microchip capillary electrophoresis-mass spectrometry for high-throughput simultaneous analysis of B-complex vitamins.

B-complex vitamins are essential micronutrients that maintaining health, and provide (individually/simultaneously) many important biological actions in organism. Therefore, sensitive, reliable analytical method to determine B-complex vitamins simultaneously in actual samples is significant. Conventional analytical methods for vitamins analysis are usually labor-intensive, time-consuming and mostly do not allow the simultaneous determination.

Achieving Electron Capture Dissociation in the Radio Frequency Linear Ion Trap without the Assistance of a Magnetic Field─A Simulation Study.

It is extremely difficult to inject a low-energy electron beam into a conventional radiofrequency (RF) linear ion trap for electron capture dissociation (ECD) without using a magnetic field to focus the electrons. In this study, the dynamic process of electrons in an RF field during their injection and transmission through a linear ion trap was simulated to determine the range of the RF phase where the electrons can be decelerated to meet the energy requirement for ECD. The ECD time window was expanded by applying a time-dependent compensation voltage to the cathode.

Development of dual-photoionization ion trap mass spectrometry and its application for direct analysis of VOCs in fruit aroma.

Photoionization-ion trap mass spectrometry (PI-ITMS) is one of the major directions of mass spectrometer miniaturization because of its great potential for rapid on-site VOCs detection in many cases. Traditionally, PI has always been investigated separately and is restrained by ion transmission structure, so a new structure needs to be designed and investigated for simplifying and improving the ion transmission efficiency. Interestingly, our preliminary experiments found that the signal intensity and mass range can be effectively improved by combing atmospheric pressure photoionization (APPI) and low-pressure photoionization (LPPI).

Enantioselective Construction of C4-Quaternary Quinolinones via Copper(II)-Catalyzed Asymmetric [1,3] O-to-C Rearrangement.

An efficient asymmetric [1,3] O-to-C rearrangement of quinolin-2(1)-ones enabled by a chiral bisoxazoline/copper complex has been developed. This strategy tolerated a wide range of substrates to provide a series of 1,4-dihydroquinoline-2,3-diones containing a quaternary stereocenter. A further cyclization of the [1,3] O-to-C rearrangement products was also realized, which led to various optically active 3,4-dihydroquinolin-2-ones with broad substrate scope.

Simulation study of three new quadrupole ion funnels to improve low-mass ion transmission.

Rationale: By applying radio frequency (RF) and direct current (DC) voltages to corresponding ring electrodes, ion funnel (IF) can efficiently focus and transmit ions. However, IF has an inherent mass discrimination problem that will greatly limit low mass-to-charge (m/z) ion focusing and transmission. To improve the transmission efficiency (TE) of the IF, this paper explores three new profile quadrupole ion funnels (QIF).

Genetic Algorithm Optimized Printed Circuit Board Ion Funnel Tandem Subambient Pressure Ionization with Nanoelectrospray (SPIN) for High Sensitivity Mass Spectrometry.

The SPIN tandem ion funnel (IF) structure allows for highly sensitive mass spectrometry due to reduced ion losses in the interface region and during transmission; however, IF has an inherent mass discrimination problem, which can greatly restrain the ion transmission efficiency (TE) and therefore requires certain optimization methods. Conventional optimization methods ignore the combined effects of multiple IF characteristic parameters (electrical and dimensional parameters) and are unable to achieve efficient ion transmission over a wide mass range, thus requiring significant tuning time. In this paper, a genetic algorithm (GA)-optimized printed circuit board ion funnel (PCBIF) was designed, fabricated, preliminarily evaluated, and integrated into the SPIN interface to address the ion loss that can occur when mass spectrometers transfer ions at subambient pressure.

Synchronized Reverse Scan Collision Induced Dissociation in Digital Ion Trap Mass Spectrometer for Improving Fragment Ion Detection.

Development of fragment ion detection methods is of great importance for mass spectrometer advancement or substance identification. To date, collision induced dissociation (CID) remains the most commonly used ion activation method in MS/MS experiments, and the effectiveness of CID in an ion trap mass spectrometer is limited by low mass cutoff and weak fragmentation yields. Theoretically, controlling the q value is the key to maintain the fragment efficiency and trapping efficiency of MS/MS, thus improving the detection of fragment ion, while currently reported techniques usually require complex circuitry and often produce different CID patterns.

Genetic algorithm parallel optimization of a new high mass resolution planar electrostatic ion trap mass analyzer.

The study and design of high-resolution mass analyzers is a very important task in mass spectrometry. A planar electrostatic ion trap (PEIT) mass analyzer with image charge detection and FT-based data processing has been developed, theoretically simulated, and experimentally validated. However, the 10 ring electrode configuration (PEIT-10) is difficult for mechanical construction and voltage tuning; moreover, few methods have been reported for optimizing the performance of multi-electrode mass analyzers.

Meckel's Cave Size Measured by Magnetic Resonance Imaging in the Prognosis of Percutaneous Balloon Compression for Trigeminal Neuralgia.

Background: Percutaneous balloon compression (PBC) is a safe and effective method to treat trigeminal neuralgia. Despite it is known that intraoperative balloon volume is crucial in the prognosis of PBC patients and correlates with Meckel's cave (MC) size, it is a lack of objective and valid criteria for intraoperative balloon volume of PBC.

Objectives: The aim of this study was to evaluate the relationship between the size of MC and the volume of a pear-shaped balloon in improving the prognosis of patients receiving PBC.

Linkage-specific identification and quantification of sialylated glycans by TIMS-TOF MS through conjugation with metal complexes.

Mass spectrometry is an indispensable technology for the characterization of glycans. However, specific identification of isomeric glycans especially sialylated glycan isomers using mass spectrometry alone is challenging, which is why orthogonal techniques are needed. Aiming to achieve simple, rapid, and specific identification of sialyl-linkage isomers, we reported herein a trapped ion mobility spectrometry time of flight mass spectrometry (TIMS-TOF MS) method for linkage-specific identification of sialylated glycans through conjugation with metal complexes.

Comparison of the Efficacy of Short-term Peripheral Nerve Stimulation and Pulsed Radiofrequency for Treating Herpes Zoster Ophthalmicus Neuralgia.

Objective: This study aimed to investigate the effect of therapy with peripheral nerve stimulation (PNS) and pulsed radiofrequency (PRF) combined or PNS and PRF separately in patients with herpes zoster ophthalmicus (HZO).

Materials And Methods: This cohort study included 106 cases of HZO. Three groups were identified according to the type of treatment received: combination therapy (PNS+PRF) (n=38), PRF (n=37), and PNS (n=31).

A Ti/Nb-functionalized COF material based on IMAC strategy for efficient separation of phosphopeptides and phosphorylated exosomes.

In this work, on the basis of an immobilized metal ion affinity chromatography enrichment strategy, a new kind of covalent organic framework (COF) material for enrichment of phosphorylated peptides and exosomes was successfully prepared in a facile method, and Ti and Nb were used as dual-functional ions (denoted as COF-S-S-COOH-Ti/Nb). With the advantage of unbiased enrichment towards phosphopeptides, COF-S-S-COOH-Ti/Nb shows ultra-high selectivity (maximum molar ratio of β-casein: BSA is 1:20,000) and low limit of detection (0.2 fmol).

Alterations in local activity and functional connectivity in patients with postherpetic neuralgia after short-term spinal cord stimulation.

Introduction: The efficacy of short-term spinal cord stimulation (stSCS) as a treatment for neuropathic pain in patients with postherpetic neuralgia (PHN) has already been validated. However, the potential alterations in brain functionality that are induced by such treatment have yet to be completely elucidated.

Methods: This study use resting-state functional magnetic resonance imaging (rs-fMRI) to detect the changes in regional homogeneity (ReHo) and degree centrality (DC) related to stimulator-induced pain relief in patients with PHN.

Nebulization Swab Assisted Photoionization Tandem Miniaturized Ion Trap Mass Spectrometry for On-Site Analysis of Nonvolatile Compounds.

Nonvolatile compounds usually have a high molecular weight and exhibit a high boiling point, which poses great challenges to the ionization method of MS. Ambient ionization sources can efficiently analyze the nonvolatile compounds without complex pretreatment, but they generally require special media such as heating devices, laser optical devices, or corona needles. Acoustic nebulization assisted photoionization (ANPI) is a potential method for the analysis of nonvolatile compounds that uses nebulization as a prerequisite for photoionization and introduces many advantages of PI, including excellent ionization efficiency, a high yield of molecular ions, and simplified spectrum interpretation.

The chirality determination of amino acids by forming complexes with cyclodextrins and metal ions using ion mobility spectrometry, and a DFT calculation.

Chiral recognition is of highly interest in the areas of chemistry, pharmaceuticals, and bioscience. An effective strategy of enantiomeric determination of amino acids (AAs) was developed in this work. All 19 natural AAs enantiomers can be easily distinguished by ion mobility-mass spectrometry of the non-covalent complexes of AAs with cyclodextrins (α-CD, β-CD and γ-CD) and Mg without any chemical derivatization.

Recognition of Cis-Trans and Chiral Proline and Its Derivatives by Ion Mobility Measurement of Their Complexes with Natamycin and Metal Ion.

Discrimination of isomers is an important and valuable feature in many analytical applications, and the identification of chiral isomers and cis-trans isomers is the current research focus. In this work, a simple method for direct, simultaneous recognition of d-/l-proline (P), d-/l-/-/-4-hydroxyproline (4-HP), and d-/l-/-/-N--butoxycarbony (N-Boc-4-HP) was investigated by means of trapped ion mobility spectrometry-mass spectrometry (TIMS-MS). The isomers with cis-/trans-/d-/l-configuration can be directly recognized based on their mobility upon reaction with natamycin (Nat) and metal ions through noncovalent interactions.

The Analysis of Percutaneous Balloon Compression on Efficacy and Negative Emotion in the Treatment of Recurrent Trigeminal Neuralgia After Surgical Procedures.

Background: Recurrent trigeminal neuralgia (TN) after surgical operations can be quite difficult to treat, and treatment measures have not been standardized. Patients often have long-term, repeated severe pain, which may easily cause anxiety and depression and can exert a negative effect on the quality of life. Despite the known efficacy of percutaneous balloon compression (PBC) for TN, it is unclear whether PBC can be used as the preferred surgical treatment for postoperative recurrent TN and effectively improve patients' negative emotions.

Identification of Bi-2-naphthol and Its Phosphate Derivatives Complexed with Cyclodextrin and Metal Ions Using Trapped Ion Mobility Spectrometry.

The separation of chiral enantiomers has gained increasing importance in many research fields, becoming a major research hotspot. 1,1'-Bi (2-naphthol) (BINOL) and 1,1'-binaphthyl-2,2'-diyl hydrogen phosphate (BNP) are referred to as atropisomer chiral molecules, which are essential chiral catalysts and intermediates in several reactions. In this work, BINOL and BNP atropisomers are separated and identified using trapped ion mobility spectrometry (TIMS) to monitor the different mobilities of their derivative complexes.

Investigation of the effect of an octopole electric field on a linear ion trap and an asymmetric semi-circular linear ion trap analyzer.

Linear ion trap mass analyzer could improve analytical performance compared to the traditional three-dimensional ion trap. In this study, a systematic investigation of the effect of octopole field on the performance of linear quadrupole ion trap was studied by both theoretical simulations and experiments. An asymmetric semi-circular linear ion trap (AsC-LIT) analyzer was designed and tested based on the theoretical results.

Application of the poly (POSS-octavinyl-co-N-methylacetamide-co-divinylbenzene) solid extraction column in analyzing preservatives.

In this study, a special poly solid-phase extraction (in-tube SPE) column consisting of poly (POSS-octavinyl-co-N-methylacetamide-co-divinylbenzene) [poly (POSS-OS-co-DVB-co-NMA)] was prepared based on the chemical structure of the preservatives, and was used as medium for extraction analysis in combination with UPLC. The composition of polymer SPE was optimized and characterized; good scanning electron microscopy (SEM) properties and satisfactory porosity were obtained with 30% monomer (POSS-OS:DVB:NMA = 2 wt%:13 wt%:15 wt%) and 70 wt% porogenic solvent (PEG20000:DMSO:ACN = 10 wt%:50 wt%:10 wt%). The experimental parameters of the in-tube SPE-UPLC analysis were optimized systematically.

Measurement of the effective electric field radius on digital ion trap spectrometer.

The effective electric field radius is a fundamental parameter of ion traps, and it has a significant influence on ion-trapping capability, signal intensity, mass range and some other properties of the ion trap. For a quadrupole ion trap built with ideal hyperbolic electrodes, its effective electric field radius can be obtained by its geometrical size, while it is very difficult to obtain the effective electric field radius for a non-hyperbolic ion trap. In this study, the effective electric field radius of a linear ion trap and some ceramic rectilinear ion traps (cRITs) were investigated via the digital ion trap technology.

Direct distinction of ibuprofen and flurbiprofen enantiomers by ion mobility mass spectrometry of their ternary complexes with metal cations and cyclodextrins in the gas phase.

Enantiomeric drugs are widely used and play important roles in pharmaceuticals. Ion mobility spectrometry coupled with mass spectrometry technology provides a unique method for distinguishing the enantiomeric drugs, enantiomeric identification, and quantitation in the gas phase. In this study, enantiomeric molecules of ibuprofen and flurbiprofen were clearly recognized by forming host-guest complex ions using trapped ion mobility time-of-flight mass spectrometry.

Direct and simultaneous recognition of the positional isomers of aminobenzenesulfonic acid by TIMS-TOF-MS.

Positional isomer recognition is a challenging scientific issue. Fast and accurate detection of isomers is required for understanding their chemical properties. Here, we describe a method for simultaneous recognition of three positional isomers of 2-aminobenzenesulfonic acid (2-ABSA), 3-ABSA, and 4-ABSA using trapped ion mobility spectroscopy-time-of-flight mass spectrometry (TIMS-TOF-MS).

Releasing bacteria from functional magnetic beads is beneficial to MALDI-TOF MS based identification.

Bacterial infections are the key cause of morbidity and mortality worldwide. Matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS)-based bacterial identification has been widely accepted in the clinic. Functional material, such as rabbit immunoglobulin G-modified FeO (IgG@FeO) and fragment crystallizable mannose binding lectin-modified FeO (FcMBL@FeO), is used to capture bacteria from biological samples for MALDI-TOF MS identification, and the bacteria MS signals are usually obtained by directly smearing enriched bacteria on a MALDI target with MALDI matrix solution.