Analysis of human luteinizing hormone and human chorionic gonadotropin preparations of different origins by reversed-phase high-performance liquid chromatography

Specific reversed-phase high-performance liquid chromatography conditions are reported for the analysis of recombinant and native human luteinizing hormone (hLH) and human chorionic gonadotropin (hCG) preparations. Heterodimeric hLH, hCG and their α- and β-subunits migrated with significantly different retention times (tR) in the following order of increasing hydrophobicity: α-hCG < α-hLH < hCG < hLH < β-hCG < β-hLH. Under these conditions, the main peak of three hCG preparations ran about 4% faster than the average tR (38.35 ± 0.42 min; RSD = 1.1%) of four hLH preparations. Four heterogeneous urinary products were also analyzed, hLH, hFSH and hCG peaks being identified. Quantitative analysis was validated for the homogeneous preparations and a highly linear dose–response curve (r = 0.99998; p < 0.0001; n = 20) used to assess the accuracy, precision and sensitivity of the analysis. Quantification of the different gonadotropins in the heterogeneous preparations was also carried out, but with limitations in accuracy.