Hydrophobic tags, derived from iodoacetamide, were synthesized, characterized, and utilized to alkylate peptide E-76, a known inhibitor of coagulation factor VIIIa, and two other cysteine containing peptides. The electrospray response of each tagged peptide was compared against the same peptide alkylated with iodoacetamide. E-76 peptide alkylated with the synthesized tags demonstrated an increase in electrospray response of up to 429 times when compared to that alkylated with iodoacetamide.