SIMULTANEOUS DETERMINATION OF COPPER, CADMIUM, LEAD AND ZINC IN NATURAL WATERS BY DIFFERENTIAL PULSE CATHODIC STRIPPING VOLTAMMETRY (DPCSV)
Individual peak locations were found by analyzing each element by itself at different concentrations. After the identification of the location of peak areas, nano-pure water was spiked with known concentrations of heavy metals to form a calibration curve. In order to optimize the prior Tris/Oxine method, all possible combinations of Tris and Oxine were tested with the following set of values: 5ul, 10ul, 20ul, 40ul, and 80ul. In addition, DPCSV (differential-pulse of cathodic-stripping voltammetry) techniques were used in place of square-wave.
Linear regression provided varying R2 values which were then used to find the optimal conditions for simultaneous determination of the four metals. Some combinations lacked peaks entirely, and were discarded. At neutral pH, in a 10mL reaction vessel, three Tris/Oxine combinations with regression values of 0.997 to 0.995 were chosen for future optimization. The importance of these results allow for determinations in different environments and at higher sensitivities.
In order for implementation to surrounding bodies of water in Queens, New York City, the concentration of Tris must be altered to maintain a neutral pH. For further studies our method will be applied to local ponds and lakes to document the concentrations of such heavy metals. It will further aid in the study of the make-up of the lakes, surrounded by human activity.