We evaluated the effect of the different solubilization techniques on the reproducibility and width of the chorionic proteome characterized using bottom-up proteomics: SDS-based solubilization coupled with in-gel protein digestion after applying self-named 1DE gel-concentration procedure (SDS-PAGE without fractionating in the resolving gel for SDS removal) and in-solution protein digestion of urea-thiourea extracts. These results indicated that 1DE-concentration procedure coupled with in-gel digestion, LC-MS/MS and combinational usage of different bioinformatics tools provides in-depth analysis of a single protein band, including reliable identification and quantification of low-abundant proteins, e.g. FUCA1, PSG7.