The separation of proteins of fetal calf serum using a MECC method was developed. The influence of pH, sample dilution, nature and concentration of buffer, concentration of surfactant and other conditions affecting the separation were optimized. The usefulness of the addition of two replaceable polymers: hydroxypropylmethylcellulose and dextran to the buffer was investigated. Although their addition had little influence on the separation, an improvement of the resolution of some group of peaks were observed. A 25 mM borate/25 mM phosphate buffer, pH=8.5. with 50 mM SDS allowed to separate the proteins of fetal calf serum, rat serum and healthy and abnormal human serum with good resolution and short analysis time. The potential of this method in clinical diagnosis is demonstrated. Using standard proteins, an assignment of some peaks in human serum was proposed. Then, the method was applied to the evaluation of a biomimetic drug carrier. The interaction of orosomucoid-coated nanoparticles with serum proteins was evidenced and compared with the one of uncoated nanoparticles. The method allowed to establish a kinetic of desorption of pre-adsorbed orosomucoid by competition with serum proteins.