The Applications Of Internal Extractive Electrospray Ionization Mass Spectrometry In Tissue Samples Analysis

Ambient mass spectrometry technique has been increasingly applied to tissue sample analysis with the advantages of high sensitivity,high speed and the capability for providing molecular structure information of compounds in complex matrices.Traditionally,the time-consuming sample pretreatment procedures including homogenization,extraction and separation are inevitable for tissue sample analysis,and commonly associated with sample preparations are chemicals contamination,biological degradation and bioactive components loss.Recently,with development of novel ambient mass spectrometry techniques,in situ tissue samples analysis become possible without any sample pretreatment,which siginificantly improved the analysis efficiency of tissue samples.This paper mainly discussed the applications of internal extractive electrospray ionization mass spectrometry(iEESI-MS)in tissue samples analysis,including plants tissue,animal tissue as well as human tissue,and prospected its development trends and significance in different fields,such as plants metabolism,food safety analysis and clinical medicine.Based on the brief overiew of the applications of traditional mass spectrometry techniques in tissue sample analysis,the main contents of this paper are as follows:1.The applications of iEESI-MS in plants tissue analysis.1)Fresh asparagus tubers together with two kinds of dry asparagus tubers were analyzed by iEESI-MS without any sample pretreatment,through collision-induced dissociation(CID)experiments,the constructure of nutrient and medicinal components including sugars,amino acids,alkaloids and rutin were confirmed.Experimental results demonstrated that established iEESI-MS makes rapid recognition of chemical composition differences in different plants tissue become possible,showing potential guiding significance in agricutural development.2)iEESI-MS was used to analyze mung bean seeds(Vigna radiata)cultured with 3 different NPs,including CdTe quantum dots(CdTe QDs),gold nano paticles(Au NPs),and silver nano particles(Ag NPs).The results showed that NPs can affect energy metabolism of mung bean sprouts.Our study lays the solid foundation for further examining other NPs-induced damaging effects such as apoptosis/necrosis,to better understand the phytotoxicity of NPs in plants.3)Iendocarp tissue samples and flesh tissues samples of navel oranges from three habitats were directly interrogated by iEESI-MS,the quality differences among navel oranges from three habitats were clearly visualized via PCA.Experimental results indicated that the quality differences of navel oranges at the molecular level can be directly characterized by iEESI-MS,showing popential reference value in quality evaluation of other fruits and vegetables.2.The applications of iEESI-MS in animal tissue analysis.1)Different meat samples were directly analyzed through iEESI-MS,the experimental results indicated that iEESI-MS could rapidly detect trace ?-agonists in meat samples at molecular level,with minimal sample preparation and simplicity of operation,which provided a novel scientific tool for high-output screening poor meat contaminated by ?-agonists.2)Rapid quantitative determination of bulk molecular concentration in solid samples without sample pretreatment is demonstrated by iEESI-MS analysis of six ?-agonists,including salbutamol,clenbuterol,ractopamine,terbutaline,tulobuterol,brombuterol in pork tissue samples.The established method for a single sample analysis was less than 1 min,the limits of detection(LOD)varied from 0.002 ?g/kg for clenbuterol to 0.855 ?g/kg for tulobuterol,the linear response range was 0.01-1000 ?g/kg,and relative standard deviation(RSD)was between 3.2% and 11.8%.The iEESI-MS analytical results were validated by gas chromatography mass spectrometry(GC-MS),showing the proximity was 91-95%.The current study extends the quantification power of ambient MS for the molecules at the surface of solid samples(e.g.in ?g/cm2 units)toward the molecules inside bulk sample volume(i.e.in ?g/kg units).3)Metabolic effects of clenbuterol and salbutamol on pork meat quality was studied using iEESI-MS,combination PCA with correlation analysis,many biomarker are related to pork quality were found.The findings suggested that clenbuterol and salbutamol may render effects on the activity of carnitine acyltransferase I,hence the process that L-carnitine transports long-chain fatty acids into mitochondria and the formation of phosphatidylcholines might be affected.3.The applications of iEESI-MS in human tissue analysis.1)With the purpose to obtain much more phospholipids with high signal intensity,the lung cancer tissue and adjacent tissue were profiled by iEESI-MS under 21 kinds of solvent system mixed CH3 OH with H2 O at certain volume ration,and achieving CH3OH:H2O = 30:70(v/v)was the best solvent system for extraction of phospholipids within cancer tissue samples.2)Under optimal experimental contidions,lung cancer tissue samples and adjacent normal tissue samples were drectly analyzed with iEESI-MS using CH3OH:H2O=30:70(v/v)as extractive solvents.The spectra data of lung cancer tissue samples and adjacent normal tissue samples was clearly differentiated via PCA,this further proved that iEESI-MS could differentiate the difference between cancer tissue and adjacent normal tissue at the molecular level,which was of great importance in probing the meanchism of phospholipids in the development of cancer,and accurately assuring the complete removal of malignant tissue.