MEKC determination of IgG in human serum via a pH-mediated acid stacking method.

An on-column preconcentration technique, pH-mediated acid stacking, was used in this study to improve the sensitivity of MEKC-UV analysis of IgG in human serum. Various parameters affecting pH-mediated acid stacking were optimized systematically. To eliminate the matrix interferences of human serum and to combine the sample pretreatment procedure with the detection methodology, silica-coated Fe(3)O(4) magnetic nanoparticles modified with N-(2-aminoethyl)-3-aminopropyl-trimethoxysilane were prepared and employed as solid phase extraction adsorbent to remove the abundant HSA from human serum. HSA was quantitatively removed by silica-coated Fe(3)O(4) magnetic nanoparticles modified with N-(2-aminoethyl)-3-aminopropyl-trimethoxysilanes without retaining IgG at pH 9.3. Under the optimum conditions, the sensitivity of IgG was improved 40.3-fold using a 100 s electrokinetic injection as compared with a 6 s hydrodynamic injection. The detection limit of IgG was found to be 0.1 mg/L, and the proposed method was successfully applied for the determination of IgG in human serum with satisfactory results.