Determination of copper and cadmium using an on-line anodic stripping voltammetry flow cell with detection by inductively coupled plasma mass spectrometry

An on-line anodic stripping voltammetry flow system was used to deposit copper and cadmium from National Institute of Standards and Technology (NIST) Standard Reference Material (SRM) 2670 Toxic Metals in Freeze-Dried Urine at a working electrode, with release of the analyte for detection by inductively coupled plasma mass spectrometry after the sample matrix was cleared from the cell. Recoveries determined against calibration graphs and by the method of standard additions were 94–115% for copper and 89–97% for cadmium. Spike recoveries for both analytes ranged from 92–106%. Elimination of the sodium-based polyatomic species at m/z= 62 and 63 remains highly efficient for up to 1 × 104µg cm–3 of sodium, whereas the use of dilute nitric acid as electrolyte gives far superior results for copper than those previously reported. Recent improvements in the system manifold design are discussed.