The detection of alkali, alkaline earth and heavy metal ions with a high-voltage capacitively coupled contactless conductivity detector (HV-(CD)-D-4) was investigated. Eight alkali, alkaline earth metal ions and ammonium could be separated in less than 4 min with detection limits in the order of 5 x 10(-8) m. The heavy metals Mn2+, Pb2+ Cd2+ Fe2+, Zn2+, Co2+, Cu2+ and Ni2+ could also be successfully resolved with a 10 mm 2-(N-morpholino)ethanesulfonic acid/DL-histidine (MES/His)-buffer. Zn2+, Co2+, Cu2+ and Ni2+ showed an indirect response. The detection limits for the heavy metals were determined to range from about 1 to 5 mum.