Mass-Spectrometry principle process.pptx

Mass spectrometry details

1. Mass Spectrometry Presented by Asha Kumari Sa Admission No- 231221207 Dept. of Molecular Biology & Biotechnology

2. What is Mass Spectrometry? Introduction: Mass spectrometry (MS) is an analytical technique used to measure the mass-to-charge ratio of ions. It is a powerful tool employed in various scientific fields, including chemistry, biochemistry, and molecular biology. MS provides detailed information about the molecular weight and structure of compounds, making it invaluable for identifying substances, quantifying components, and understanding molecular structures. Components of a Mass Spectrometer: 1 Ion Source: Where the sample is ionized. Common sources include ESI and MALDI. 2 Mass Analyzer: Separates ions based on their mass-to-charge ratio. Common types are Quadrupole, TOF, and Orbitrap. 3 Detector: Measures the number of ions and their abundance, converting this information into a mass spectrum.

3. Principles of Mass Spectrometry 1 Ionization The goal is to convert neutral atoms or molecules into ions. Various ionization methods are available, including Electrospray Ionization (ESI), Matrix-Assisted Laser Desorption/Ionization (MALDI), and others. This process involves introducing a sample into the ion source, where it is ionized to form positively or negatively charged ions. 2 Mass Analysis Ions are separated based on their mass-to-charge ratio (m/z) using various techniques. Quadrupole utilizes oscillating electric fields for m/z filtering. Time-of-Flight (TOF) measures the time it takes for ions to travel a fixed distance, with lighter ions traveling faster. Orbitrap determines m/z by measuring the frequency of ion oscillation in an electric field. The mass analyzer detects and separates ions, which then generate a mass spectrum. 3 Detection The detector quantifies and analyzes ions. It measures ion abundance and produces a mass spectrum, plotting ion abundance against m/z.

4. Matrix-Assisted Laser Desorption/ Ionization Time-of-Flight (MALDI-TOF) Sample Preparation The sample is mixed with a matrix material, which helps absorb the laser energy. Laser Desorption/Ionization A laser beam strikes the sample, causing desorption and ionization of the molecules. Time-of-Flight Analysis Ions are accelerated in an electric field, and their flight times are measured. Detection The detector records the abundance of ions based on their flight times.

5. Detailed Mechanism of MALDI-TOF MS Sample Preparation: Matrix Selection: Organic molecule (e.g., CHCA) absorbs laser light and assists ionization. Sample Mixing: Mix sample with matrix in a solvent, then apply to metal target plate. Sample Application: Deposition: Dry sample-matrix mixture forms a crystalline layer on the target plate. Ionization: Laser Desorption/Ionization: Laser energy is absorbed by the matrix, causing desorption and ionization of sample molecules. Desorption: Matrix vaporizes rapidly, carrying sample molecules into the gas phase. Ionization: Matrix helps ionize sample molecules by transferring protons or creating negative ions. Time-of-Flight (TOF) Analysis: Acceleration: Ions are accelerated by an electric field, gaining kinetic energy. Drift: Ions travel through a drift region; lighter ions move faster and reach the detector sooner. Detection: Time-of-flight data is collected and used to generate a mass spectrum. Data Analysis: Mass Spectrum Generation: Converts time-of-flight data into a spectrum showing m/z vs. intensity. Peak Identification: Peaks represent ions; their position indicates mass-to-charge ratio

6. Electrospray Ionization Mass Spectrometry (ESI-MS) 1 Sample Introduction The liquid sample is introduced into the electrospray source. 2 Electrospray Formation A high voltage is applied to the liquid, creating a fine mist of charged droplets. 3 Desolvation and Ionization The droplets evaporate, leading to a buildup of charge density and the formation of gas-phase ions. 4 Mass Analysis The ions are then separated based on their m/z in the mass analyzer, generating a mass spectrum.

7. Detailed Mechanism of ESI-MS Ionization Mechanism ESI is a soft ionization technique that creates ions from liquid samples. Droplet Evaporation Charged droplets formed in the electrospray source undergo rapid evaporation, leading to a concentration of charge and eventually, the formation of ions. Mass Analysis The ions are separated based on their m/z in a mass analyzer, allowing for identification and quantification of analytes. Advantages ESI is suitable for analyzing large biomolecules and is compatible with liquid chromatography for complex sample analysis.

8. Applications of Mass Spectrometry Proteomics MS is widely used in proteomics to identify, quantify, and characterize proteins in biological samples. Agriculture MS is instrumental in agricultural research, including pesticide residue analysis, nutrient profiling, disease detection, and quality control. Food Safety MS techniques are used to detect food adulteration, allergens, and contaminants, ensuring food safety and quality. Medical Diagnostics MS is employed in clinical diagnostics to identify biomarkers for diseases, monitor drug efficacy, and analyze patient samples.

9. Conclusion In conclusion, mass spectrometry is a versatile and powerful analytical technique with wide-ranging applications in various fields, including proteomics and agriculture. The detailed understanding of its principles and techniques, particularly MALDI-TOF and ESI-MS, provides a strong foundation for further exploration and development in these areas. Thank You Thank you for your time and attention