Q-TOF Peptide Map Analysis Steps

The Q-TOF (Quadrupole-Time of Flight) mass spectrometer is a mass spectrometry device that combines quadrupole and Time of Flight (TOF) technologies. It combines the selective ion transmission of quadrupole mass spectrometry and the high resolution, high precision measurement capabilities of Time of Flight mass spectrometry. It is often used for peptide mass spectrometry analysis, especially in protein identification and proteomics research. The Q-TOF mass spectrometer characteristic of peptide determination is high mass accuracy and high resolution.

 

Analysis Workflow

1. Sample Preparation

(1) Protein Extraction: Proteins are extracted from biological samples.

(2) Protein Digestion: Proteins are digested into peptides using enzymes (like trypsin).

 

2. Peptide Separation

(1) HPLC: Appropriate column and gradient conditions are selected, and mixed peptides are separated by High Performance Liquid Chromatography (HPLC).

 

3. Mass Spectrometry Analysis

(1) Peptide Ionization: In the Q-TOF ion source, peptides are ionized and converted into gaseous ions.

(2) Parent Ion Selection: The quadrupole selects specific parent ions to enter the collision unit.

(3) Collision-Induced Dissociation: Parent ions are energized and dissociated into daughter ions in the collision unit.

(4) Time of Flight Analysis: The m/z values of daughter ions are measured by the TOF analyzer.

 

4. Data Processing and Analysis

(1) Peptide Identification: Peptide sequences are identified by matching the fragment ion spectra of peptides with predicted or database spectra.

(2) Protein Identification: Corresponding proteins are identified by associating identified peptides.

(3) Quantitative Analysis: If a quantitative experiment is performed, the abundance changes of peptides under different samples or conditions need to be compared.

(4) Bioinformatics Analysis: Delve into the biological significance of proteins and modifications.

 

5. Result Validation

(1) Check whether the identified proteins are consistent with the experimental background and purpose.

(2) Further validation experiments should be performed on important proteins or peptides, such as re-performing mass spectrometry analysis or other biochemical experiments.