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An on-line supercritical fluid extraction coupled with supercritical fluid chromatography-quadrupole tandem mass spectrometry method was developed to determine lipids related to inflammation in brain tissues of depressed rats. The analysis of 23 lipids from extraction to separation and detection only took 15 min and required 1 mg of brain tissue powder. The matrix effect of the on-line method for endogenous lipids was systematically investigated, and targeted lipids were quantified by matrix effect corrected calibration curves in this study. The on-line method was comprehensively optimized and evaluated. All calibration curves for lipids showed good linearity (correlation coefficient >0.99). The limits of detection and the limits of quantification were in the range of 0.0261-0.396 pg and 0.0791-1.20 pg. The recoveries and the matrix effect were in the range of 85.3-117.5% and 51.9-176.6%, respectively. The relative standard deviations of precision ranged from 2.7 to 14.2%, with accuracies higher than 87.2%. Compared with liquid-liquid extraction coupled with liquid chromatography-tandem mass spectrometry method, the on-line method obtained higher recovery and sensitivity with significantly reduced analytical time, manual operations, and sample amounts. Finally, this on-line method was applied to analyses of brain tissues of depressed rats. Six pro-inflammatory lipids increased in depressed rats, while six anti-inflammatory lipids decreased. Liquiritin and fluoxetine were presumed to promote a similar synthesis of anti-inflammatory lipids. Based on the results, this on-line method showed great promise in analyzing lipids in complex biological samples., Competing Interests: Declaration of Competing Interest The authors report no declarations of interest., (Copyright © 2021 Elsevier B.V. All rights reserved.)

The pseudotargeted lipidomics method integrates the advantages of untargeted andtargeted lipidomics methods as a novel emerging approach. In this study, a green andefficient pseudotargeted lipidomics method based on ultra-high performancesupercritical fluid chromatography-tandem mass spectrometry (UHPSFC-MS/MS) wasdeveloped. The tandem mass spectra of the analytes were obtained by using UHPSFCwith quadrupole-time of flight MS (Q-TOF MS) in MS E mode and the multiplereaction monitoring (MRM) transitions of the lipidome were defined. Then, thecandidate MRM transitions were verified by UHPSFC with triple quadrupole massspectrometry (QqQ MS) in the scheduled MRM mode. In total, 758 potential lipidscorresponding to 509 and 249 MRM transitions were detected within 8 min in positiveand negative modes, respectively. The established pseudotargeted lipidomics methodwas validated to have excellent analytical characteristics. Compared with thepseudotargeted method based on ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS), the UHPSFC-MS/MS-basedpseudotargeted method not only reduced the analytical time by half but also improvedthe sensitivity and resolution for most analytes, especially had better separation forlipid isomers. Besides, the UHPSFC-MS/MS-based pseudotargeted method showedhigher sensitivity and better repeatability for most analytes than the UHPSFC-MS/MS-based untargeted method. The established method was finally applied to investigatingthe lipid profiles of the plasma from the depressed rats and 33 differential variableswere screened, which related to three metabolic pathways. The results indicated thatthe UHPSFC-MS/MS-based pseudotargeted method is reliable and efficient and couldbe used in the lipidomics studies., Competing Interests: Declaration of Competing Interest The authors declare no conflicts of interest., (Copyright © 2020 Elsevier B.V. All rights reserved.)

A fully automatic system, which integrated cross used solid-phase extraction with ultra-high performance liquid chromatography-tandem mass spectrometry, was developed and validated for the simultaneous determination of multi-class pharmaceuticals (62 in total) in Milli-Q water, tap water, lake water, and ground water. The online system allowed the cross-utilization of two SPE columns without significant carryover and achieved an automatic, sensitive and fast analysis, requiring about 14 min per analysis. The features of the online system were systematically investigated and the analytical conditions were fully optimized. Sixty-two pharmaceuticals were divided into two groups (acidic and basic) under different extraction conditions to increase the extraction efficiency. Under optimal conditions, all the correlation coefficients were greater than 0.9929. The LODs and the LOQs were in the range of 0.00119-0.623 ng L -1 and 0.00475-2.49 ng L -1 , respectively. The RSDs% for the intra-/inter-day precision were less than 10.6% and 15.6%, respectively. The system recoveries ranged from 80.7 to 119.9%. Compared with the offline SPE method, the online cross used SPE-UHPLC-MS/MS method obtained higher sensitivity and reduced manual operations. Compared with the existing online SPE systems, this system can reduce the time per analysis. Finally, this online system was applied to the analyses of three real water samples. Based on the results, the online cross used SPE-UHPLC-MS/MS system as an automatic, sensitive and efficient technique showed great promise for the future in the trace analysis of multi-class pharmaceuticals in complex aqueous samples., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Isosteviol sodium (STV-Na) was reported to possess significant protective effects on ischemic stroke in recent years. However, the protective mechanism of STV-Na against stroke was still unclear. In this work, an untargeted lipidomics approach based on the ultra high-performance supercritical fluid chromatography coupling with ion-trap and time-of-flight tandem mass spectrometry (UHSFC-IT-TOF/MS) was employed to investigate the lipid profiles of stroke rats with STV-Na treatment for the first time. The possible mechanism of STV-Na was further elucidated. The UHSFC-IT-TOF/MS-based method achieved a fast separation of various lipids within 9 min with a qualified repeatability. Multivariate statistical analysis was used to show differences in lipid profiles induced by stroke and STV-Na treatment. The results showed a clear separation of the model group and the sham group, with the STV-Na group as well as EDA group located much closer to the sham group than the model group, which was consistent with the results of physiological and pathological assays, indicating the protective effects of STV-Na. Fifteen differential lipids that presented significant differences between the sham group and the model group were screened and identified. With the treatment of STV-Na, 15 differential lipids in stroke rats showed a tendency to the normal levels. Among them, 6 lipids were significantly reversed to the normal levels by STV-Na. The results of pathway analysis suggested the protective effects of STV-Na might be related to the regulation of several metabolic pathways including glycerophospholipid metabolism, arachidonic acid metabolism and sphingolipid metabolism. This work demonstrated that the UHSFC-IT-TOF/MS-based lipidomics profiling method was a useful tool to investigate the protective effects of STV-Na against stroke., (Copyright © 2018 Elsevier B.V. All rights reserved.)