Capillary electrophoresis-mass spectrometry of basic proteins using a new physically adsorbed polymer coating. Some applications in food analysis.
A new physically adsorbed capillary coating for capillary electrophoresis-mass spectrometry (CE-MS) of basic proteins is presented, which is easily obtained by flushing the capillary with a polymer aqueous solution for two min. This coating significantly reduces the electrostatic adsorption of a group of basic proteins (i.e., cytochrome c, lysozyme, and ribonuclease A) onto the capillary wall allowing their analysis by CE-MS. The coating protocol is compatible with electrospray inonization (ESI)-MS via the reproducible separation of the standard basic proteins (%RSD values (n = 5) < 1% for analysis time reproducibility and < 5% for peak heights, measured from the total ion electropherograms (TIEs) within the same day). The LODs determined using cytochrome c with total ion current and extracted ion current defection were 24.5 and 2.9 fmol, respectively. Using this new coating lysozymes from chicken and turkey egg white could be easily distinguished by CE-MS, demonstrating the usefulness of this method to differentiate animal species. Even after sterilization at 120 degrees C for 30 min, lysozyme could be detected, as well as in wines at concentrations much lower than the limit marked by the EC Commission Regulation. Adulteration of minced meat with 5% of egg-white could also be analysed by our CE-MS protocol.
Simó
Carolina
C
Institute of Industrial Fermentations (CSIC).
Elvira
Carlos
C
Institute of Science and Technology of Polymers (CSIC).
González
Nieves
N
Institute of Science and Technology of Polymers (CSIC).
San Román
J
J
Institute of Science and Technology of Polymers (CSIC).
Barbas
Coral
C
Department of Analytical Chemistry, University San Pablo-CEU, Madrid, Spain.
Cifuentes
Alejandro
A
Institute of Industrial Fermentations (CSIC).
D000327:Adsorption; D000818:Animals; D045304:Cytochromes c / Q000032:analysis; D004529:Egg White / Q000032:analysis; D019075:Electrophoresis, Capillary / Q000379:methods*; D005504:Food Analysis; D013058:Mass Spectrometry / Q000379:methods*; D008460:Meat / Q000032:analysis; D009113:Muramidase / Q000032:analysis; D011108:Polymers / Q000737:chemistry*; D011506:Proteins / Q000032:analysis* / Q000737:chemistry; D012259:Ribonuclease, Pancreatic / Q000032:analysis; D055672:Static Electricity; D013997:Time Factors
D011108:Polymers; D011506:Proteins; D045304:Cytochromes c; D012259:Ribonuclease, Pancreatic; D009113:Muramidase