Second hand mass spectrometerIt is a precision scientific instrument used for analyzing the composition and structure of substances, playing a key role in many fields such as chemistry, physics, biology, and environmental science. Its working principle is based on precise measurement of the motion behavior of charged particles in electromagnetic fields. The sample is first ionized and converted into charged ions. These ions are accelerated in an electric field and then enter a magnetic field. Under the action of a magnetic field, ions will undergo deflection, and the degree of deflection of ions with different mass to charge ratios (the ratio of ion mass to charge) varies, resulting in specific signal distributions on the detector, namely mass spectra. By analyzing the position, intensity, and other information of each peak on the mass spectrum, the molecular weight, structure, and relative content of different components in the sample can be determined.
Second hand mass spectrometerIts main functions can be summarized as follows:
1. Determine the relative molecular weight of a substance
Mass spectrometer can directly provide molecular weight information of substances through the mass to charge ratio signal of ions. For example, in organic chemistry, the relative molecular mass of a compound can be quickly determined by the molecular ion peak (M ⁺) in the mass spectrum, providing a key basis for the structural identification of unknown substances.
For macromolecular substances (such as proteins and peptides), the accurate molecular weight can be measured through soft ionization technology (such as electrospray ionization ESI, matrix assisted laser desorption ionization MALDI) to help the characterization of biological macromolecules.
2. Analyze the chemical composition and structure of substances
Qualitative analysis of components: By using the mass to charge ratio of characteristic ions in the mass spectrum, combined with database searches (such as NIST mass spectrometry library), the types of elements, functional groups, or compounds contained in the sample can be determined. For example, pollutants in water (such as pesticide residues and heavy metal ions) can be identified through mass spectrometry in environmental testing.
Structural analysis: The fragment ion peak in the mass spectrum reflects the fragmentation mode of the molecule, and the molecular structure of the compound can be inferred by combining the fragment pattern. For example, in drug development, analyzing the mass spectrometry fragments of drug metabolites can clarify metabolic pathways and product structures.
3. Quantitative analysis of substance content
Based on the principle that "ion signal intensity is proportional to substance concentration", mass spectrometer can quantitatively analyze target components in samples. Combined with chromatography techniques such as gas chromatography (GC) and liquid chromatography (LC), precise quantification of trace components in complex samples can be achieved (detection limits can reach ppb or even ppt levels).
Application scenarios include: detection of additive or toxin content in food, monitoring of drug concentration in blood, analysis of pollutant content in the environment, etc.
4. Study the isotopic composition of substances
Mass spectrometers can accurately measure the differences in mass to charge ratios of different isotopes, thereby analyzing the abundance ratios of isotopes in substances. For example:
In geology, the formation age and paleoenvironmental temperature of rocks or fossils can be inferred by measuring the ratio of carbon isotopes (¹² C/¹³ C) and oxygen isotopes (¹⁶ O/¹⁸ O).
In biology, stable isotope labeling (such as ¹⁵ N labeling of amino acids) is used to track the metabolic pathways of substances in organisms through mass spectrometry.
5. Characterizing the characteristics of biomolecules
In the field of life sciences, mass spectrometry is a core tool for proteomics and metabolomics research
Can identify the amino acid sequence of proteins (through peptide mass spectrometry analysis), post-translational modifications (such as phosphorylation and glycosylation), and reveal the functions and regulatory mechanisms of proteins.
Analyze the metabolite composition in biological samples (such as blood and urine) and search for disease biomarkers (such as potential indicators for early diagnosis of cancer).
6. Environmental and safety testing
Quickly screen for toxic and harmful substances in the environment, such as volatile organic compounds (VOCs) in the atmosphere, persistent organic pollutants (POPs) in water, heavy metals in soil, etc.
In the field of security inspection, it can be used to detect characteristic ions of prohibited items such as explosives and toxins, achieving rapid identification (such as trace substance detection at airports and stations).