Analysis of metal-diethyldithiocarbamate (DDC) complexes by high-performance liquid chromatography (HPLC) is affected by the stability of the complexes and their interactions with the metal components of the instrument. Using a reversed-phase stainless steel column, good separation of Co(III)-, Cr(III)-, Cu(II)- Hg(II)-, Ni(II)-, Pd(II)-, Pt(II)-, Se(IV)-, and Te(IV)-DDC complexes can be achieved using ACN-H2O (70:30) as a mobile phase. Ligand exchange with Ni from the stainless steel column prohibits quantitative analysis of some metal-DDC complexes with lower stability constants relative to that of Ni. The exchange reaction can be eliminated with a metal-free PEEK column. Separation of Bi(III)-, Cd(II)-, Fe(II)-, In(III)-, Pb(II)-, Tl(I)-, and Zn(II)-DDC complexes, which is not feasible using a stainless steel column, can be achieved using a PEEK column and MeOH-H2O-CHCI3 (75:20:5) as the mobile phase. Pyrrolidinedithiocarbamate (PDC) offers no advantage over DDC in HPLC analysis of metal complexes.