MALDI Matrix Selection
Matrix-Assisted Laser Desorption/Ionization (MALDI) is a soft ionization method where the 'matrix' is determined by the type of molecule to be detected. The matrix is added in excess to the sample to be analyzed and irradiated with a laser to vaporize the analyte molecules, thus producing positively and negatively charged ions.
The selection of a MALDI matrix is one of the most crucial steps in its analysis. The matrix co-crystallizes with the analyte and absorbs laser energy to prevent direct laser irradiation from damaging the analyte, reducing interactions between analyte molecules. The analyte sample is dispersed within the matrix, which effectively absorbs the energy of the pulsed laser at a certain wavelength and then uniformly transmits it to the sample, causing the sample to evaporate and ionize instantly. The large amount of matrix effectively disperses the analyte sample, thereby reducing interactions between analyte molecules.
In conventional MALDI detection, the analyte sample is mixed into and surrounded by the matrix. The matrix molecules absorb the laser energy and transfer a portion of it to the analyte sample (e.g., proteins, nucleic acids). Different types of analyte samples have varying requirements for the matrix, thus choosing an appropriate matrix is fundamental to successfully detecting target molecules.
The choice of MALDI matrix mainly depends on the wavelength of the laser used and the nature of the analyte. Typically, highly polar analytes work better in highly polar matrices, and nonpolar analytes are best used with nonpolar matrices. Different types of samples and target focuses may require different matrices. An ideal matrix usually has the following characteristics: strong electronic absorption at the laser wavelength used, good vacuum stability, low vapor pressure, and good miscibility with solid-state analytes. Commonly used matrices include α-cyano-4-hydroxycinnamic acid (CHCA), 2,5-dihydroxybenzoic acid (DHB), sinapinic acid (SA), 2,4,6-trihydroxyacetophenone (THAP), dithranol (DI), 3-indoleacrylic acid (IAA), etc.
Biotech company BGI offers a high-throughput mass spectrometry platform providingMALDI-TOF-MS mass spectrometry identificationanalysis services suitable for the identification of proteins with a molecular weight below 25kDa. You only need to send us your requirements and samples, and we will handle all subsequent matters, including sample pre-treatment, MALDI-TOF-MS mass spectrometry analysis, raw data analysis, and bioinformatics analysis.
Related services:
Molecular weight determination
High-resolution mass spectrometry molecular weight identification
Protein molecular weight determination
Molecular weight determination of protein complexes and protein-small molecule complexes
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