a system is disclosed for voltammetry such as anodic stripping voltammetry including a special electrode mounted to be fitted into a sample holder , stirring means operable through the electrode and an electrolytic potential source , optionally pulsed , capable of scanning the operating potential range which may for example , be a range between about - 1 volt and 0 volt . output recording means can be either an analog chart output or digitalized output . the system may be employed for a wide variety of test purposes generally relating to identifying and measuring heavy metals , one of which is detecting and measuring trace mineral components or trace elements in samples of human blood . when employed with blood samples the sample may first be prepared in the usual manner including digesting the sample but the presently preferred procedure comtemplate that the metals being tested are first displaced from blood complexing with a suitable ion such as cr 3 + or ca 2 + and the operating potential from about - 800 millivolts to nearly 0 volt is scanned to read out the presence and quantity of metal such as lead , cadmium , copper and the like . an analysis of such metals can be run in as little as a minute . the ratio of electrode area to sample volume disclosed is 4cm 2 per 1 . 0 milliliter . a self contained test composition is disclosed .