Part II: Everything You Need to Know About Metabolomics Research

Part I: Everything You Need to Know About Metabolomics Research

Matrix-assisted laser desorption/ionization (MALDI) is a mild ionization method that can obtain intact mass spectrometry information of some macromoleculars which are easily dissociated into fragments by conventional ionization methods, such as DNA, proteins, peptides and sugars. Matrix-assisted laser desorption/ionization (MALDI) is a mild ionization method that can obtain intact mass spectrometry information of some macromoleculars which are easily dissociated into fragments by conventional ionization methods, such as DNA, proteins, peptides and sugars. Desorption electrospray ionization (DESI) is a direct ionization technique that allows direct analysis of samples under atmospheric conditions with tandem mass spectrometry. The principle is to use a fast moving charged solution stream to extract samples of the contact surface, which can be used for forensic analysis, analysis of drugs, plants, biological tissues, polymers, etc. Laser ablation electrospray Ionization (LAESI) is a direct ionization technique that combines mid-infrared laser ablation and secondary electrospray ionization for a wide range of samples, including plants, tissues, cells, and even untreated biological solutions such as blood, urine, and so on. It has been used in the fields like food and drug regulation.

metabolomics analysis
 Nuclear magnetic resonance spectrum does not need to separate the metabolic components in advance. Compared with mass spectrometry, it has the advantages of good reproducibility, simple sample preparation, no prior separation, and low destructiveness to the sample. Although its sensitivity phase is lower (It is controversial. Some scholars believe that this is caused by incorrect sample pretreatment workflow), its ease-to-use feature makes it a widely used method.

Apart from the above ones, there are other detection methods, which include ion-mobility spectrometry (IMS), electrochemical detection techniques coupled with high-performance liquid chromatography (HPLC-ECD) and Raman spectroscopy. IMS is a technique for separating and analyzing these molecules based on the migration of ionized molecules in a gas phase carrier. It has high sensitivity and can be used alone or in series with mass spectrometry, gas chromatography or liquid chromatography. HPLC-ECD can be used to measure low-level components in complex matrices. It has the features of ease-to-use, sensitivity and selectivity, and has been used in clinical research, food testing, drug testing and other fields. Raman spectroscopy is based on vibrational spectroscopy and is capable of detecting compound structures and small changes. It has the advantages of not destroying samples, easy sample preparation, and high spatial resolution. It is applied to clinical pathology research, microbial classification and detection, compound analysis and other fields.

Metabolomics Related Databases and Commonly Used Software

metabolomics
Commonly used metabolomics related databases include the Human Metabolome Database (HMDB), the Small Molecule Pathway Database (SMPDB), the Kyoto Encyclopedia of Genes and Genomes (KEGG), and the Reactome database, the MassBank database, the BioCyc database, the METLIN database, the FiehnLib database, the NIST/EPA/NIH Mass Spectral Library database, the MetaCyc database, the MMCD database, etc. 

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