Data independent acquisition for gas chromatographic MS/MS analysis of volatile compounds.

This study presents a novel tandem mass spectrometry (MS/MS) approach utilizing a data independent acquisition (DIA) concept specifically designed with gas chromatography-electron ionization-triple quadrupole mass spectrometry (GC-EI-QqQMS). This allows compound identification based on comparison between all the experimental MS/MS product ion spectra and the simulated library data of >1,000 MS/MS transitions of 71 compounds. The simulation data were generated by using the Competitive Fragmentation Modeling (CFM-ID) 3.0 program. The approach for calculation of the DIA MS/MS library match scores was then established and applied for identification of a range of terpenoids and oxygenated compounds in perfume. The identity of each peak was confirmed using 4-241 MS/MS transitions. The established data collection and analysis methods are expected to be useful for increased confidence in volatile compound analysis.

[Rapid chemome characterization of Pien-Tze-Huang by DI-MS/MS~(ALL)].

Pien-Tze-Huang, one of the most famous and widely used Chinese medicinal prescriptions in China, consists of Notoginseng Radix et Rhizoma, Bovis Calculus, Fel Serpentis, and Moschus.The prescription can clear heat and remove toxin, cool blood and resolve blood stasis, and relieve swelling and pain.Characterizing the chemical composition can facilitate the construction of the quality standard and the research on the effective compounds and action mechanism of Pien-Tze-Huang.Therefore, this study used direct infusion(DI)-MS/MS~(ALL) method to rapidly and accurately reveal the chemical composition of Pien-Tze-Huang.The principle of chemical composition profiling of Chinese medicinal prescriptions lies in the MS~1-MS~2 dataset construction, followed by structural annotation based on MS/MS spectra and summarizing of mass fragmentation pathways.MS/MS~(ALL) owns unique mass spectrometric separation ability via applying gas phase fractionation which enables MS~1 ion cohort successively enter the collision cell and acquire MS~2 spectrum for each precursor ion current with a width of m/z=1.Because DI can provide desired measurement time, MS/MS~(ALL) is able to acquire MS~2 spectrum for each compound individually except for the compounds which share identical nominal molecular weight, even isomers.A total of 52 compounds were identified in Pien-Tze-Huang, including 16 saponins, 24 bile acids, 9 fatty acids, 2 saccharides, and 1 other compound.DI-MS/MS~(ALL) can simultaneously identify the compounds with different polarities in a short time, which is superior to LC-MS.This study provides a powerful tool for the rapid chemome profiling of Chinese medicinal prescriptions.

Chemical mutagenesis and high throughput media optimization in Tolypocladium inflatum MTCC-3538 leads to enhanced production of cyclosporine A.

Diethyl sulphate-based mutagenesis was performed on fungal strain Tolypocladium inflatum MTCC-3538. Two mutant morphotypes MT1-3538 and MT2-3538 were selected for further chemo-profiling studies. LCMS/MS profiling of fungal crude extract confirmed that the wild-type and mutant strains (MT1-3538, MT2-3538) were competent to produce cyclosporine A. MT2-3538 produced 2.1 fold higher cyclosporine A in comparison to the wild type. Further, LCMS-based high throughput media optimization was performed for MT2-3538 in 20 different media combinations to increase cyclosporine A yield. On the basis of ion-intensity profiling, media combination consisting of Glucose 0.1 g/L; Peptone 0.005 g/L and Valine 0.005 g/L was selected and used for up-scaling purpose. Mutant MT2-3538 with optimized media combination increased cyclosporine yield 16 fold and could potentially be exploited for commercial outcomes. Supplementary Information: The online version contains supplementary material available at 10.1007/s13205-022-03219-x.

Mobile monitoring of VOCs and source identification using two direct-inlet MSs in a large fine and petroleum chemical industrial park.

Mobile monitoring with direct-inlet MS (DI-MS), one of the most direct and effective ways to track emission sources, can effectively serve air quality management in chemical industrial parks (CIPs). Mobile monitoring using a high mass-resolution proton-transfer-reaction time-of-flight MS (HMR-PTR-TOFMS) and single-photon ionization time-of-flight MS (SPI-TOFMS) was conducted in a large fine and petroleum CIP in eastern China for three days. The high mixing ratios of aliphatic hydrocarbons (AHs), aromatics, oxygenated VOCs (OVOCs), and nitrogenous VOCs (NVOCs) were found in the northeast, middle, north, and northeast of the fine chemical industrial zone (FCIZ), respectively. OVOCs were the most abundant VOC group in this area. Abnormal emissions of aromatics were universal throughout the CIP. We discovered 38 characteristic VOCs by the HMR-PTR-TOFMS, mainly including C6-C10 aromatics, C2-C6 carbonyls, C2-C3 organic acids, and some NVOCs. The time series and spatial distribution of the TVOCs obtained by the two DI-MSs are generally consistent. A comparison of the speciated VOCs at the TVOC peak points illustrates that the characteristic VOCs obtained by different instruments differed significantly: PTR-TOFMS showed an advantage in measuring aromatics and OVOCs; SPI-TOFMS showed an advantage in measuring aromatics and some Ahs; offline GC-MS showed an advantage in measuring AHs, aromatics, some OVOCs, and halohydrocarbons. Similarities were compared between five positive matrix factorization (PMF) model-based fingerprints of VOCs in a previous study and observed profiles of VOCs from mobile monitoring. The emission sources of the five fingerprints were identified and validated: two were widely distributed, one was a chemical reagent production factory, one was an acrylic fiber production plant, and one was a pesticide factory. This study demonstrated methods for analyzing mobile monitoring data, characterizing the VOCs in the fine and petroleum CIP, correlating the results of stationary observation and mobile monitoring, and integrating the source tracing system with DI-MSs.

[Rapid chemome profiling of Cistanche salsa using DI-MS/MS~(ALL)].

The current study aims to rapidly and comprehensively profile the chemical composition of Cistanche salsa using direct infusion coupled with MS/MS~(ALL)(DI-MS/MS~(ALL)). The C. salsa extract was directly imported into electrospray ionization(ESI) source of quadrupole time-of-flight(Q-TOF) mass spectrometer with an infusion pump at a flow rate of 10 µL·min~(-1). Acquisition program was applied under negative ionization polarity to collect one MS~1 spectrum(m/z 50-1 200), followed by 1 150 MS~2 spectra with precursor isolation window(m/z 1) amongst mass range m/z 50-1 200. After each MS~2 spectrum was matched to its precursor ion, putative identification was conducted through matching mass spectral data with literature and database. A total of 31 components were identified from C. salsa, including 9 phenylethanoid glycosides, 2 iridoids, 4 saccharides, 9 organic acids, and 7 other compounds, similar to those from C. tubulosa and C. deserticola. In conclusion, DI-MS/MS~(ALL), a facile and reliable analytical tool, can be employed for qualitative analysis of chemical constituents in C. salsa. The research offers a promising strategy to achieve rapid chemome profiling of herbal medicine and provides an alternative source of Cistanches Herba.

Integrative Metabolomic and Lipidomic Profiling of Lung Squamous Cell Carcinoma for Characterization of Metabolites and Intact Lipid Species Related to the Metastatic Potential.

SQCC is a major type of NSCLC, which is a major cause of cancer-related deaths, and there were no reports regarding the prediction of metastatic potential of lung SQCC by metabolomic and lipidomic profiling. In this study, metabolomic and lipidomic profiling of lung SQCC were performed to predict its metastatic potential and to suggest potential therapeutic targets for the inhibition of lung SQCC metastasis. Human bronchial epithelial cells and four lung SQCC cell lines with different metastatic potentials were analyzed using gas chromatography-mass spectrometry and direct infusion-mass spectrometry. Based on the obtained metabolic and lipidomic profiles, we constructed models to predict the metastatic potential of lung SQCC; glycerol, putrescine, ß-alanine, hypoxanthine, inosine, myo-inositol, phosphatidylinositol (PI) 18:1/18:1, and PI 18:1/20:4 were suggested as characteristic metabolites and intact lipid species associated with lung SQCC metastatic potential. In this study, we established predictive models for the metastatic potential of lung SQCC; furthermore, we identified metabolites and intact lipid species relevant to lung SQCC metastatic potential that may serve as potential therapeutic targets for the inhibition of lung SQCC metastasis.

Stationary monitoring and source apportionment of VOCs in a chemical industrial park by combining rapid direct-inlet MSs with a GC-FID/MS.

Fast and comprehensive monitoring of VOCs, required for air quality management in large-scale chemical industrial parks in China, cannot be accomplished by stationary measurements using conventional GC-FID or GC-MS alone due to their low temporal resolutions and limited detectable ranges. Novel direct-inlet mass spectrometry (DI-MS) has been widely applied for real-time monitoring of VOCs. To verify its applicability in industrial settings, high mass-resolution proton-transfer-reaction time-of-flight MS (HMR-PTR-TOFMS), single-photon ionization time-of-flight MS (SPI-TOFMS), together with online GC-FID/MS were simultaneously deployed at the boundary of one of the largest chemical industrial parks in eastern China. Aromatics, acetonitrile, acetic acid, ethyl acetate, aliphatic hydrocarbons, 1,2-dichloroethane, and acetone were detected as the main pollutants. These three instruments detected 12 common species, among which ethyl acetate, toluene, C8-aromatics, and methyl ethyl ketone showed similar time series and levels. Acetone, benzene, chlorobenzene, styrene, and C9-aromatics showed only similar time series. The HMR-PTR-TOFMS uniquely detected 14 species, mainly oxidized VOCs, nitriles, and amines, which greatly helps acknowledge the pollutants in the chemical industrial area. Positive matrix factorization, using the HMR-PTR-TOFMS and GC-FID/MS datasets, was used to identify eight sources. Four of the identified sources were mainly detected by the HMR-PTR-TOFMS, with pollutants mainly comprised of nitriles, amines, carbonyls, and organic acids, most of which were hazardous and/or odorous. These four sources accounted for 41.5% and 33.2% of the total VOCs and ozone formation potential, respectively. The complementary nature of GC-FID/MS and HMR-PTR-TOFMS in VOC source apportionment in industrial settings is of great practical use for advanced VOCs abatement. Thus, the high mass resolution DI-MSs are suggested to be a supplementary measurement for fence-line monitoring. Although with a relatively short period attempt, this study has wide implications for the fence-line stationary observational modes and source apportion methods combining with traditional observations.

[Rapid chemome profiling of chemical components of Lonicerae Japonicae Flos using DI-MS/MS~(ALL)].

A new method of MS/MS~(ALL) was designed to sequentially record a MS~2 spectrum at each unit mass window through gas phase fractionation concept, so as to offer an opportunity for universal MS~2 spectral recording with direct infusion(DI). As a proof-of-concept, DI-MS/MS~(ALL) was applied for rapid chemome profiling of a famous herbal medicine named Lonicerae Japonicae Flos. After each MS~2 spectrum was correlated to its precursor ion, the structural annotation was conducted by applying well-defined mass cracking rules, matching the mass spectral data with literatures and referring to those accessible databases. As a result, a total of 54 components were identified from Lonicerae Japonicae Flos extract, including 21 phenolic acids, 13 flavonoids, 12 iridoids, 4 triterpenoids and 4 other compounds. Therefore, DI-MS/MS~(ALL) is a powerful tool for comprehensive, rapid qualitative analysis of chemical profiles of traditional Chinese medicine and other chemical components of complex systems.

Characterization and classification of rat neural stem cells and differentiated cells by comparative metabolic and lipidomic profiling.

It is necessary to characterize and classify neural stem cells (NSCs) and differentiated cells (DCs) for potential use of NSC to treat neurodegenerative diseases. We therefore performed an analysis of NSCs and DCs using gas chromatography mass spectrometry (GC-MS) and direct infusion mass spectrometry (DI-MS) with elaborate multivariate statistical analysis for the characterization and classification of rat NSCs and DCs. GC-MS and DI-MS detected a total of 92 metabolites and lipids in NSCs and DCs, and the levels of 72 of them differed significantly between NSCs and DCs. The optimal model for partial least squares (PLS) discriminant analysis was constructed by applying 3 and 2 PLS components with a unit-variance scaling method for classifying NSCs and DCs based on the data obtained in the GC-MS and DI-MS analyses, respectively. The obtained results from PCA and PLS-DA suggest that creatinine, lactic acid, lysine, glutamine, glycine, pyroglutamic acid, PG 18:1/20:2, PS 18:0/20:2, PI 18:0/20:3, PC 16:0/20:4, PI 16:0/20:4, and PI 18:1/20:4 were the main contributors that provided distinct characteristics of NSCs and DCs. The results of this study suggest objective and complementary criteria for the characterization and classification of NSCs and DCs for potential clinical applications. Graphical abstract.

Phycobiliproteins Production Enhancement and Lipidomic Alteration by Titanium Dioxide Nanoparticles in Synechocystis sp. PCC 6803 Culture.

This study aimed to improve the production of phycobiliproteins using TiO2 nanoparticles (NPs) in Synechocystis sp. PCC 6803. The growth characteristics of Synechocystis cells were not affected by TiO2 NPs treatment, but this treatment increased the chlorophyll content significantly by 62.2% (14.6 mg/L) compared to that of control (9.0 mg/L) on day 16. Phycocyanin production was increased by 33.8% (29.3 g/L) compared to that of control (21.9 g/L) on day 8. Allophycocyanin production was increased by 55.0% (6.2 g/L) compared to that of control (4.0 g/L) on day 8, and by 22.4% (16.4 g/L) compared to that of control (13.4 g/L) on day 16. Direct infusion mass spectrometry revealed that TiO2 NPs treatment significantly increased the levels of major thylakoid membranes of monogalactosyldiacylglycerols (18:2/18:3, 18:2/18:2, 18:1/18:2), phosphatidylglycerol (16:0/16:1), and sulfoquinovosyldiacylglycerols (16:0/16:1, 16:0:18:4) on day 8. These findings indicate that TiO2 NPs have potential for commercial applications in Synechocystis species or other microalgal strains.

Direct Infusion-Tandem Mass Spectrometry (DI-MS/MS) Analysis of Complex Lipids in Human Plasma and Serum Using the Lipidyzer™ Platform.

Lipids play a key role in the signaling pathways of cancer, cardiovascular, diabetic, and inflammatory diseases. A major challenge in the analysis of lipids is the many isobaric interferences present in highly complex samples that confound identification and accurate quantitation. After obtaining the total lipid extract from a sample, differential mobility separation has proven to be a powerful tool for gas-phase fractionation of lipid classes. When combined with mass spectrometry, this allows the unambiguous identification and thus quantification of lipid molecular species. These components, sample extraction, gas-phase separation, and mass spectrometry, form the basis of a novel integrated quantitative lipid analysis platform.