A solid phase extraction flow injection spectrophotometric method for the zinc determination in plants

A solid phase extraction flow injection system for the spectrophotometric determination of total zinc in plant digests was developed. Solid phase extraction was chosen as a strategy for zinc preconcentration and removal of some interferences. The determination of zinc was based on the colorimetric reaction with Zincon. As detection system, a multi-reflection flow cell coupled with a light emitting diode was used. The analytical characteristics of the methodology such as pH of standard/sample solution, nitric acid concentration, the placement of SPE column within the manifold and preconcentration flow rate were studied. The interference of some metals present in plants was also assessed. The limits of detection and quantification achieved were 0.04 mg L− 1 and 0.12 mg L− 1, respectively. The corresponding Zincon consumption was 0.17 mg for each determination. The developed system was applied to plant digests and the results obtained were in agreement with those obtained with reference procedure.