Measurement of very low-molecular weight metabolites by traveling wave ion mobility and its use in human urine samples.

The collision cross-sections (CCS) measurement using ion mobility spectrometry (IMS) in combination with mass spectrometry (MS) offers a great opportunity to increase confidence in metabolite identification. However, owing to the lack of sensitivity and resolution, IMS has an analytical challenge in studying the CCS values of very low-molecular-weight metabolites (VLMs ≤ 250 Da). Here, we describe an analytical method using ultrahigh-performance liquid chromatography (UPLC) coupled to a traveling wave ion mobility-quadrupole-time-of-flight mass spectrometer optimized for the measurement of VLMs in human urine samples.

Accurate Prediction of Ion Mobility Collision Cross-Section Using Ion's Polarizability and Molecular Mass with Limited Data.

The rotationally averaged collision cross-section (CCS) determined by ion mobility-mass spectrometry (IM-MS) facilitates the identification of various biomolecules. Although machine learning (ML) models have recently emerged as a highly accurate approach for predicting CCS values, they rely on large data sets from various instruments, calibrants, and setups, which can introduce additional errors. In this study, we identified and validated that ion's polarizability and mass-to-charge ratio (/) have the most significant predictive power for traveling-wave IM CCS values in relation to other physicochemical properties of ions.

Traveling Wave Ion Mobility-Derived Collision Cross Section Database for Plant Specialized Metabolites: An Application to Pierre.

The combination of ion mobility mass spectrometry (IM-MS) and chromatography is a valuable tool for identifying compounds in natural products. In this study, using an ultra-performance liquid chromatography system coupled to a high-resolution quadrupole/traveling wave ion mobility spectrometry/time-of-flight MS (UPLC-TWIMS-QTOF), we have established and validated a comprehensive CCS and MS database for 112 plant specialized metabolites. The database included 15 compounds that were isolated and purified in-house and are not commercially available.

Application of cup-shaped trilactams for selective extraction of volatile compounds by gas chromatography-mass spectrometry.

Chiral cyclic trilactams ((+)-1 and (-)-1) with C symmetry were investigated as liquid phase extraction materials of volatile compounds. Perfume samples, involving a range of chiral odor active terpenoids, were applied and each sample before and after the liquid phase extraction was analyzed by solid phase microextraction (SPME)-gas chromatography hyphenated with mass spectrometry. It was found that (+)-1 exhibited significantly higher enrichment factors for several terpenoids, while (-)-1 did not.

Time-Dependent Density Functional Theory Investigation of Excited State Intramolecular Proton Transfer in Tris(2-hydroxyphenyl)triazasumanene.

Previously, our group reported dual-emission spectra for tris(2-hydroxyphenyl)triazasumanene (OHPhTAS), comprising three OH···N-type intramolecular hydrogen bonds from three phenolic rings connected to the nitrogen-doped buckybowl skeleton, corresponding to the excited state intramolecular proton transfer (ESIPT) in the solid state. However, the dual emission is not observed in a nonpolar solution. In this study, the mechanism and multiplicity of potentially photoinduced dynamic ESIPT were investigated both in ground (S) and in excited states (S) by time-dependent density functional theory calculations.