Thin-layer preparation (MALDI)

The thin film preparation is a type of preparation in the MALDI method for the matrix , ie for the substance in which the analyte to improve the desorption and ionization is embedded.

In a thin-layer preparation, the matrix is dissolved in a rapidly volatile solvent ( ethanol , acetone ) and applied to a sample carrier (for example a steel plate). The rapid evaporation causes many very small crystals to form . The fine crystalline matrix then serves as a base for applying the analyte solution. Suitable for thin film preparation is in particular the matrix α-cyano-4-hydroxycinnamic acid ( English α-cyano-4-hydroxycinnamic acid , CHCA) as these typically is not soluble in aqueous solvent. The presented crystals act as crystallization nuclei and as an affine surface to which peptides bind well - but not contaminants such as salts or other MALDI interfering substances. The resulting preparation is therefore well suited for purification and is particularly uniform due to the many small matrix crystals, so that "sweet spot hunting" is less necessary.

Individual evidence

↑ M. Schuerenberg, C. Luebbert, H. Eickhoff, M. Kalkum, H. Lehrach, E. Nordhoff: α-Cyano-4-hydroxycinnamic Acid Affinity Sample Preparation. A Protocol for MALDI-MS Peptide Analysis in Proteomics , in: Anal. Chem. 2001 , 73 , 434-448; doi : 10.1021 / ac001241s .

[1] M. Schuerenberg, C. Luebbert, H. Eickhoff, M. Kalkum, H. Lehrach, E. Nordhoff: α-Cyano-4-hydroxycinnamic Acid Affinity Sample Preparation. A Protocol for MALDI-MS Peptide Analysis in Proteomics , in: Anal. Chem. 2001 , 73 , 434-448; doi : 10.1021 / ac001241s .