Stepped-up development of accelerator mass spectrometry method for the detection of ^(60)Fe with the HI-13 tandem accelerator

The Moon provides a unique environment for investigating nearby astrophysical events such as supernovae.Lunar samples retain valuable information from these events,via detectable long-lived“fingerprint”radionuclides such as^(60)Fe.In this work,we stepped up the development of an accelerator mass spectrometry(AMS)method for detecting^(60)Fe using the HI-13tandem accelerator at the China Institute of Atomic Energy(CIAE).Since interferences could not be sufficiently removed solely with the existing magnetic systems of the tandem accelerator and the following Q3D magnetic spectrograph,a Wien filter with a maximum voltage of±60 kV and a maximum magnetic field of 0.3 T was installed after the accelerator magnetic systems to lower the detection background for the low abundance nuclide^(60)Fe.A 1μm thick Si_(3)N_(4) foil was installed in front of the Q3D as an energy degrader.For particle detection,a multi-anode gas ionization chamber was mounted at the center of the focal plane of the spectrograph.Finally,an^(60)Fe sample with an abundance of 1.125×10^(-10)was used to test the new AMS system.These results indicate that^(60)Fe can be clearly distinguished from the isobar^(60)Ni.The sensitivity was assessed to be better than 4.3×10^(-14)based on blank sample measurements lasting 5.8 h,and the sensitivity could,in principle,be expected to be approximately 2.5×10^(-15)when the data were accumulated for 100 h,which is feasible for future lunar sample measurements because the main contaminants were sufficiently separated.

Ultra-soft Desorption Assisted Mass Spectrometry using Picosecond Infrared Laser for the Detection of lons in the Liquid Surface

To identify the species in liquid surface using mass spectrometry,we must eliminate or reduce interferences during the vaporization or desorption of the species from the liquid surface.It is much more challenging to isolate the ionic,larger species from the liquid surface,because of the frangible structures and the higher solvation energies of those species.Here we demonstrate a new mass spectrometry in which the ionic species at the liquid surface can be desorbed with ultrasoft infrared picosecond laser pulses while the liquid surface is not breached.This laser desorption assisted mass spectrometry is not only a powerful tool to detect the fragile species but also promising to investigate vibrational energy transfer dynamics in the liquid surface.

Determination of 14 Organophosphorus Pesticide Residues in Mutton by Gel Permeation Chromatography-Gas Chromatography-Mass Spectrometry(GPC-GC-MS)

[Objectives]This study was conducted to purify mutton samples by gel permeation chromatography(GPC).[Methods]Fourteen organophosphorus pesticide residues in samples were qualitatively and quantitatively analyzed by gas chromatography-mass spectrometry(GC-MS)in selective ion scanning mode(SIM).[Results]The organophosphorus pesticide standard solutions showed good linearity in the mass concentration range of 0.1-10.0μg/ml with correlation coefficients(r)not lower than 0.999,and the detection limits(S=3 N)ranged from 0.01 to 0.05 mg/kg.The average recovery values were in the range of 80.2%-99.7%,with relative standard deviations(RSDs,n=3)in the range of 1.8%-6.3%,at the addition levels of 0.5,1.0 and 2.0 mg/kg.[Conclusions]The method is simple,sensitive and accurate,and can be used for the determination of organophosphorus pesticide residues in mutton.

Research on the Upper Limit of Accuracy for Predicting Theoretical Tandem Mass Spectrometry

In recent years, numerous theoretical tandem mass spectrometry prediction methods have been proposed, yet a systematic study and evaluation of their theoretical accuracy limits have not been conducted. If the accuracy of current methods approaches this limit, further exploration of new prediction techniques may become redundant. Conversely, a need for more precise prediction methods or models may be indicated. In this study, we have experimentally analyzed the limits of accuracy at different numbers of ions and parameters using repeated spectral pairs and integrating various similarity metrics. Results show significant achievements in accuracy for backbone ion methods with room for improvement. In contrast, full-spectrum prediction methods exhibit greater potential relative to the theoretical accuracy limit. Additionally, findings highlight the significant impact of normalized collision energy and instrument type on prediction accuracy, underscoring the importance of considering these factors in future theoretical tandem mass spectrometry predictions.

Chemical profiling of bioactive compounds in the methanolic extract of wild leaf and callus of Vitex negundo using gas chromatographymass spectrometry

BACKGROUND The investigation of plant-based therapeutic agents in medicinal plants has revealed their presence in the extracts and provides the vision to formulate novel techniques for drug therapy.Vitex negundo(V.negundo),a perennial herb belonging to the Varbanaceae family,is extensively used in conventional medication.AIM To determine the existence of therapeutic components in leaf and callus extracts from wild V.negundo plants using gas chromatography-mass spectrometry(GCMS).METHODS In this study,we conducted GC-MS on wild plant leaf extracts and correlated the presence of constituents with those in callus extracts.Various growth regulators such as 6-benzylaminopurine(BAP),2,4-dichlorophenoxyacetic acid(2,4-D),α-naphthylacetic acid(NAA),and di-phenylurea(DPU)were added to plant leaves and in-vitro callus and grown on MS medium.RESULTS The results clearly indicated that the addition of BAP(2.0 mg/L),2,4-D(0.2 mg/mL),DPU(2.0 mg/L)and 2,4-D(0.2 mg/mL)in MS medium resulted in rapid callus development.The plant profile of Vitex extracts by GC-MS analysis showed that 24,10,and 14 bioactive constituents were detected in the methanolic extract of leaf,green callus and the methanolic extract of white loose callus,respectively.CONCLUSION Octadecadienoic acid,hexadecanoic acid and methyl ester were the major constituents in the leaf and callus methanolic extract.Octadecadienoic acid was the most common constituent in all samples.The maximum concentration of octadecadienoic acid in leaves,green callus and white loose callus was 21.93%,47.79%and 40.38%,respectively.These findings demonstrate that the concentration of octadecadienoic acid doubles in-vitro compared to in-vivo.In addition to octadecadienoic acid;butyric acid,benzene,1-methoxy-4-(1-propenyl),dospan,tridecanedialdehyde,methylcyclohexenylbutanol,chlorpyrifos,n-secondary terpene diester,anflunine and other important active compounds were also detected.All these components were only available in callus formed in-vitro.This study showed that the callus contained additional botanical characteristics compared with wild plants.Due to the presence of numerous bioactive compounds,the medical use of Vitex for various diseases has been accepted and the plant is considered an important source of therapeutics for research and development.

Determination of Ten Kinds of Alpha-2 Agonists Residues in Animal Derived Food by UHPLC-Triple Quadrupole/Composite Linear Ion Trap Mass Spectrometry

[Objectives]The paper was to establish an ultra high performance liquid chromatography-quadrupole/linear ion trap complex mass spectrometry for the determination of 10 kinds ofα2-receptor agonists in animal derived food.[Methods]The samples were extracted with sodium carbonate buffer solution and ethyl acetate,and analyzed by mass spectrometry after solid phase extraction and high performance liquid chromatography separation.[Results]Ten kinds ofα2-receptor agonists showed a good linear relationship in the range of 1-100μg/mL,with the average recovery of over 69%and the relative standard deviation less than 8.32%.The detection limit of 10 kinds of α_(2)-receptor agonists was up to 1μg/kg.[Conclusions]The method has good selectivity and strong anti-interference ability,and can meet the requirements of 10 kinds ofα2-receptor agonists residues in animal derived food.

基于FT-ICR MS表征达古冰川冬春季节表层雪中DOM分子组成变化

分析冰川中溶解性有机质(dissolved organic matter,DOM)的迁移转化特征是评估冰川消融对下游生态环境效应的重要依据,但冰川表层雪中DOM在冬春季节的迁移转化特征尚不明确。本文以达古冰川冬春季节表层雪和春季冰川径流为研究对象,使用傅里叶变换离子回旋共振质谱(FT-ICR MS)对表层雪和径流中DOM进行分子层次表征。结果显示:达古冰川冬春季节表层雪中DOM化学组成非常丰富,主要包括脂类、多肽类、不饱和烃类,还含有少量的酚类、多环芳烃类和糖类,来源包括微生物活动和陆源性输入。春季径流中DOM的主要来源是陆源性输入,受人类活动影响较大。分析不同季节表层雪DOM的分子组成变化,发现冬季低温环境有利于表层雪中脂类、多肽类和含S类DOM分子的富集,春季气温升高则有利于表层雪中多肽类、不饱和烃类和含N类DOM分子的富集。比较春季径流和表雪中DOM的分子组成变化,发现径流中杂原子类DOM含量降低,微生物来源的脂类和多肽类DOM含量降低,陆源性的酚类和多环芳烃类含量显著增加,说明径流中DOM的生物活性降低而光反应活性增加。因此随着冰川持续消融大量的冰川融水将DOM带入下游水环境,在微生物活动和光反应过程的共同作用下增加温室气体CO_(2)的排放,增强温室效应。

基于FT-ICR MS表征煤焦化废水处理过程有机物分子组成变化

有效去除水溶性有机质(DOM)是废水处理的一项重要内容,但DOM分子组成及其在处理过程中的变化规律并不明确。本文以一整套煤焦化废水为研究对象,通过液-液萃取和固相萃取分离得到不同极性的水相有机质组分,使用傅里叶变换离子回旋共振质谱(FT-ICR MS)对所得的有机质进行分子层次表征。油相和水相有机质的水溶性总有机碳(TOC)比例基本一致,随着处理过程的进行,废水的“油性”越来越弱,能溶解在二氯甲烷中的有机质越来越少,最后所剩的主要是一些难以降解的腐殖质类物质;而水相有机质具有极其复杂的分子组成,在单一质谱图中共鉴定出70余种不同种类的化合物,这些化合物,尤其是O_(4)S_(1)类化合物,虽然在废水处理过程中有很好的去除效果,但在最终出水中仍有残留。

Molecular transformation of dissolved organic matter in refinery wastewaters: Characterized by FT-ICR MS coupled with electrospray ionization and atmospheric pressure photoionization

Dissolved organic matter(DOM)in refinery wastewater is an extremely complex mixture of various organic compounds.Using mass spectrometry,it is impossible to characterize all of the DOM molecules with only one ionization source.In this study,negative-ion,electrospray ionization(ESI),positive-ion ESI,and positive-ion atmospheric pressure photoionization(APPI)were coupled with Fourier transform ion cyclotron resonance mass spectrometry(FT-ICR MS)to analyze the molecular composition of DOM in a refinery wastewater stream during the treatment process.There were obvious differences in the heteroatom composition,number of DOM constituents,and chemical properties in refinery wastewater under the three ionization modes.Acidic CHO and CHOS compounds detected by(+)ESI,basic CHN and CHON compounds detected by(þ)ESI,and hydrocarbons detected by(+)APPI were analyzed to determine the molecular transformations that occurred during treatment.In an anaerobic biological treatment process,acidic CHO and CHOS compounds with a high oxygen content were preferentially removed,and acidic CHO and CHOS compounds with a low oxygen content were produced.In an aerobic biological process,acidic CHO and CHOS compounds with a low oxygen content were preferentially removed,and acidic CHO and CHOS compounds with a high oxygen content were produced.The whole biological treatment process has a poor removal efficiency for CHN and CHON compounds,and hydrocarbons.An activated carbon(AC)adsorption process removed different heteroatom compounds mainly with a low oxygen content for acidic and basic compounds.The transformation mechanism of CHO and CHOS compounds in the biological treatment process was analyzed by the Kendrick mass defect(KMD)theory and a mass difference network analysis.In the anaerobic process,large amounts of oxygenated CHO and CHOS compounds were degraded by decarboxylation,deoxydation,demethoxylation,and dehydration reactions,and converted to lower oxygen content compounds.In the aerobic processes,these low oxygen CHO and CHOS compounds mainly underwent carboxylation and oxidation reactions.This study determined the transformation characteristics and mechanisms of different types of organic compounds in refinery wastewater during the treatment process.The results provide guidance for the design and optimization of technologies for refinery wastewater treatment.

Neurotoxicity mechanism of aconitine in HT22 cells studied by microfluidic chip-mass spectrometry

Aconitine,a common and main toxic component of Aconitum,is toxic to the central nervous system.However,the mechanism of aconitine neurotoxicity is not yet clear.In this work,we had the hypothesis that excitatory amino acids can trigger excitotoxicity as a pointcut to explore the mechanism of neurotoxicity induced by aconitine.HT22 cells were simulated by aconitine and the changes of target cell metabolites were real-time online investigated based on a microfluidic chip-mass spectrometry system.Meanwhile,to confirm the metabolic mechanism of aconitine toxicity on HT22 cells,the levels of lactate dehydrogenase,intracellular Ca^(2+),reactive oxygen species,glutathione and superoxide dismutase,and ratio of Bax/Bcl-2 protein were detected by molecular biotechnology.Integration of the detected results revealed that neurotoxicity induced by aconitine was associated with the process of excitotoxicity caused by glutamic acid and aspartic acid,which was followed by the accumulation of lactic acid and reduction of glucose.The surge of extracellular glutamic acid could further lead to a series of cascade reactions including intracellular Ca^(2+)overload and oxidative stress,and eventually result in cell apoptosis.In general,we illustrated a new mechanism of aconitine neurotoxicity and presented a novel analysis strategy that real-time online monitoring of cell metabolites can provide a new approach to mechanism analysis.

Spatiotemporal pharmacometabolomics based on ambient mass spectrometry imaging to evaluate the metabolism and hepatotoxicity of amiodarone in HepG2 spheroids

Three-dimensional(3D)cell spheroid models combined with mass spectrometry imaging(MSI)enables innovative investigation of in vivo-like biological processes under different physiological and pathological conditions.Herein,airflow-assisted desorption electrospray ionization-MSI(AFADESI-MSI)was coupled with 3D HepG2 spheroids to assess the metabolism and hepatotoxicity of amiodarone(AMI).High-coverage imaging of>1100 endogenous metabolites in hepatocyte spheroids was achieved using AFADESI-MSI.Following AMI treatment at different times,15 metabolites of AMI involved in Ndesethylation,hydroxylation,deiodination,and desaturation metabolic reactions were identified,and according to their spatiotemporal dynamics features,the metabolic pathways of AMI were proposed.Subsequently,the temporal and spatial changes in metabolic disturbance within spheroids caused by drug exposure were obtained via metabolomic analysis.The main dysregulated metabolic pathways included arachidonic acid and glycerophospholipid metabolism,providing considerable evidence for the mechanism of AMI hepatotoxicity.In addition,a biomarker group of eight fatty acids was selected that provided improved indication of cell viability and could characterize the hepatotoxicity of AMI.The combination of AFADESI-MSI and HepG2 spheroids can simultaneously obtain spatiotemporal information for drugs,drug metabolites,and endogenous metabolites after AMI treatment,providing an effective tool for in vitro drug hepatotoxicity evaluation.

Untargeted and targeted mass spectrometry reveal the effects of theanine on the central and peripheral metabolomics of chronic unpredictable mild stress-induced depression in juvenile rats

L-theanine has been shown to have a therapeutic effect on depression.However,whether L-theanine has an excellent preventive effect on depression in children and adolescents and what its mechanism is have not been well explained.Given the complexity of the pathogenesis of depression,this study investigated the preventive effect and mechanism of L-theanine on depression in juvenile rats by combining serum and hippocampal metabolomic strategies.Behavioral tests,hippocampal tissue sections,and serum and hippocampal biochemical indexes were studied,and the results confirmed the preventive effect of Ltheanine.Untargeted reversed-phase liquid chromatography-quadrupole-time-of-flight mass spectrometry and targeted hydrophilic interaction liquid chromatography-triple quadrupole mass spectrometry were developed to analyze the metabolism changes in the serum and hippocampus to screen for potential biomarkers related to L-theanine treatment.The results suggested that 28 abnormal metabolites in the serum and hippocampus that were considered as potential biomarkers returned to nearnormal levels after L-theanine administration.These biomarkers were involved in various metabolic pathways,mainly including amino acid metabolism and lipid metabolism.The levels of amino acids and neurotransmitters in the phenylalanine,tryptophan,and glutamic acid pathways were significantly reduced after L-theanine administration compared with chronic unpredictable mild stress-induced rats.In summary,L-theanine had a significant preventive effect on depression and achieved its preventive results on depression by regulating various aspects of the body,such as amino acids,lipids,and inflammation.This research systematically analyzed the mechanism of L-theanine in preventing depression and laid the foundation for applying L-theanine to prevent depression in children and adolescents.

FT-ICR MS解析水中DOM化学多样性及分子转化特性

针对溶解性有机物(DOM)组成极具复杂性、难以从分子水平研究其化学多样性的问题,该文基于FT-ICR MS超高分辨质谱技术建立了水体DOM的分子组成和化学多样性的表征方法:通过可视化分析发现水中DOM是以CHO元素组成的木质素/富羧酸脂环分子为主体;揭示了氯消毒过程中DOM的分子转化规律,证实DOM中CHO分子的主要转化途径为木质素/富羧酸脂环分子氧化并裂解生成高含氧化合物;识别了氯消毒后生成的氯代消毒副产物分子,其中最主要的副产物类型为氯代多酚类化合物。实验结果表明了FT-ICR MS技术在解析DOM化学多样性及分子转化特性的优势,为多种复杂环境下DOM分子层面转化研究提供了强有力的支撑。

Application of Mass Spectrometry (MS)-coupled Techniques in Pesticide Residue Detection

Pesticide residue detection is an important work to ensure the quality safety of agricultural products.In the process of agricultural production,in order to prevent and control agricultural diseases and pests,a certain amount of pesticides need to be used.However,if pesticides are used excessively,there will be certain pesticide residues in crops and related products.Therefore,it is necessary to do a good job in pesticide residue detection.The gas chromatography-mass spectrometry(GC-MS)and liquid chromatography-mass spectrometry(LC-MS)detection methods have good results and can effectively detect pesticide residues in related products.This paper reviewed and analyzed the application of GC-MS and LC-MS in pesticide residue detection,and proposed optimization measures based on practical experience,hoping to provide reference for relevant scholars.

Determination of Veterinary Drug Residues in Animal-derived Foods by Liquid Chromatography-Mass Spectrometry

[Objectives]This study was conducted to establish a rapid and effective method for simultaneous extraction of 54 kinds of veterinary drug residues in animal-derived food, including sulfonamides, quinolones, tetracyclines, malachite greens, penicillins, nitroimidazoles, tranquilizers and macrolides, by HPLC-MS. [Methods] The samples were extracted with 80% acetonitrile water(containing 0.1% formic acid), combined with QuEChERS extraction technology and C18 and PSA purification, analyzed by high performance liquid chromatography-mass spectrometry, and quantified by external standard method. The target substances were analyzed on ZORBAX Eclipse C18 chromatographic column using 0.2% formic acid water and 0.2% methanol as mobile phases. The gradient elution mode was used for chromatographic separation and multiple reaction detection. [Results] In the linear range of 0.5-50.0 ng/ml, the linear relationship of the 54 kinds of veterinary drug residues was good, with correlation coefficients(r~2) greater than 0.995, and the detection limits ranged from 0.30 to 1.00 μg/kg. The results showed that the recovery ranged from 75.4% to 118.2% when different matrixes were added for recovery. [Conclusions] This method is simple, efficient, accurate, stable, and highly operable. It is applicable to simultaneous batch screening of veterinary drug residues in animal-derived food, and has high practical application value.

Evaluation of allergenic protein profiles in three Chinese high-oleic acid peanut cultivars using NanoLC-Orbitrap mass spectrometry

High oleic-acid peanuts are known for their pre-longed shelf-life and health benefit due to high content of oleic fatty acid.However,the allergenicity and allergenic protein profiles in Chinese high-oleic peanuts have yet to be studied.For this purpose,an Orbitrap Fusion mass spectrometry(MS)-based method that is feasible for identification of putative allergenic protein as well as semi-quantitation of five major allergen protein in three different Chinese high-oleic peanut cultivars(JH 13,JH 16 and JH 18)have been reported.Results show that three Chinese high-oleic acid peanut cultivars selected all contained highly allergenic proteins Ara h1,Ara h 2,Ara h 3 and Ara h 6.The allergenic protein profiles of Chinese high-oleic acid peanut cultivars were very similar to that of conventional peanuts,but the allergenic protein subunits varied greatly among higholeic peanuts.Additionally,a comprehensive peptide-filtering pipeline had been developed for identification of potential peptide markers in peanut allergen proteins.Through the peptide-filtering pipeline,three novel peptide markers,IVQIEAKPNTLVLPK,SSNPDIYNPQAGSLR and AQSENYEYLAFK surrogate to Ara h 1,Ara h 3 with high abundance,good MS response and highly reliability were identified,which can be used as candidate peptide markers for the detection of peanut allergens in different food matrices.

Resin composition: An indicator of oil maturity as revealed by fourier transform ion cyclotron resonance mass spectrometry

A pyrolysis experiment was carried out on a Dongying Depression kerogen sample to separate the resin from the oil. Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) with a positive-ion detector was used to detect the relative proportional changes in the compounds of the resin. During the whole pyrolysis experiment, the relative ratio of resin exceed 10% of the soluble component at each temperature point. Five compounds were detected from the resin: N1, N1O1, N1O_(2), O1, and O_(2). To research the changes in the proportions of the compounds during pyrolysis clearly, these five compounds were divided into three classes: N1, N1Ox, and Ox. The N1 class has the largest proportion in resin at the beginning of the pyrolysis, while Ox class has the least proportion. And the relationship between the number and the molecular mass of three classes compound was researched. With increasing maturity, the proportion of N1 and the N1Ox class decreased rapidly, while the Ox class increased slowly. Through researching these resin compounds, it was found that an inversion in the proportions of above three compounds appeared at the end of the oil window. At the same time, we found that the DBE and carbon number of resin compounds have changed obviously during the pyrolysis: the DBE increased, while the carbon number decreased significantly. And the details of the change of each compound have been researched. This research extends our knowledge of judging the maturity of crude oil during the pyrolysis through the characteristics of compounds in resin and provides the new index based on resin for the evaluation of thermal evolution stage and hydrocarbon generation capacity of source rocks.

Nylon 6-cellulose composite hosted in a hypodermic needle: Biofluid extraction and analysis by ambient mass spectrometry in a single device

This study proposes a hypodermic needle(HN)as a sorbent holder and an electrospray(ESI)emitter,thus combining extraction and analysis in a single device.A novel nylon 6-cellulose(N6-Cel)composite sorbent is proposed to extract methadone from oral fluid samples.The cellulosic substrate provides the composite with high porosity,permitting the flow-through of the sample,while the polyamide contributes to the extraction of the analyte.The low price of the devices(considering the holder and the sorbent)contributes to the affordability of the method,and their small size allows easy transportation,opening the door to on-site extractions.Under the optimum conditions,the analyte can be determined by high-resolution ambient ionization mass spectrometry at a limit of detection(LOD)as low as 0.3 mg/L and precision(expressed as relative standard deviation,RSD)better than 9.3%.The trueness,expressed as relative recovery(RR),ranged from 90%to 109%.As high-resolution mass spectrometers are not available in many laboratories,the method was also adapted to low-resolution spectrometers.In this sense,the direct infusion of the eluates in a triple quadrupole-mass spectrometry provided an LOD of 2.2 mg/L.The RSD was better than 5.3%,and the RR ranged from 96%to 121%.

Determination of Voriconazole in Human Plasma by Liquid Chromatography Tandem Mass Spectrometry: Application in Therapeutic Drug Monitoring

A sensitive, accurate and robust Liquid Chromatography Tandem Mass Spectrometry method has been developed and validated to measure voriconazole trough levels in human plasma. The plasma samples were mixed with fluconazole as an Internal Standard and directed to protein precipitation and drug extraction. An aliquot of 1 μl was injected into the chromatographic system and separated by the Acquity BEH C18 column at a flow rate of 0.30 ml/min in a gradient mobile phase consisting of acetonitrile, Ultrapure water (UPW), methanol and formic acid. Voriconazole was detected by a Triple Quadrupole Detector (TQD) operating on Multiple Reaction Monitoring (MRM) and a positive ion mode Electrospray ionization (ESI) Q1 mass: 350.1 m/z, Q3 mass: 281.1 m/z. Method linearity of the calibration curve (0.10 - 8.00 μg/ml) indicated a correlation coefficient r ≥ 0.99. The intra and inter-assay accuracy was within 85% - 115% and the intra and inter-assay precision was ≤5.76%. Voriconazole recovery percentage was between 97.69 - 119.62%. The method was successively applied in routine voriconazole TDM.

Integrated mass spectrometry imaging reveals spatial-metabolic alteration in diabetic cardiomyopathy and the intervention effects of ferulic acid

Diabetic cardiomyopathy(DCM)is a metabolic disease and a leading cause of heart failure among people with diabetes.Mass spectrometry imaging(MSI)is a versatile technique capable of combining the molecular specificity of mass spectrometry(MS)with the spatial information of imaging.In this study,we used MSI to visualize metabolites in the rat heart with high spatial resolution and sensitivity.We optimized the air flow-assisted desorption electrospray ionization(AFADESI)-MSI platform to detect a wide range of metabolites,and then used matrix-assisted laser desorption ionization(MALDI)-MSI for increasing metabolic coverage and improving localization resolution.AFADESI-MSI detected 214 and 149 metabolites in positive and negative analyses of rat heart sections,respectively,while MALDI-MSI detected 61 metabolites in negative analysis.Our study revealed the heterogenous metabolic profile of the heart in a DCM model,with over 105 region-specific changes in the levels of a wide range of metabolite classes,including carbohydrates,amino acids,nucleotides,and their derivatives,fatty acids,glycerol phospholipids,carnitines,and metal ions.The repeated oral administration of ferulic acid during 20 weeks significantly improved most of the metabolic disorders in the DCM model.Our findings provide novel insights into the molecular mechanisms underlying DCM and the potential of ferulic acid as a therapeutic agent for treating this condition.