Experimental designs in the development of a new method for the sensitive determination of cadmium in seawater by adsorptive cathodic stripping voltammetry

• Published in: Analytica chimica acta 2003-07, Vol.487 (2), p.229-241
• Main Authors: Jurado-González, José A, Galindo-Riaño, Marı́a D, Garcı́a-Vargas, Manuel
• Format: Article
• Language: English
• Subjects: 2-Acetylpyridine salicyloylhydrazone; Adsorptive cathodic stripping voltammetry; Analytical chemistry; Applied sciences; Cadmium; Chemistry; Electrochemical methods; Exact sciences and technology; Natural water pollution; Pollution; Seawater; Seawaters, estuaries; Water treatment and pollution
• ISSN: 0003-2670; 1873-4324
• DOI: 10.1016/S0003-2670(03)00536-1

A new differential pulse adsorptive cathodic stripping voltammetric (DPAdCSV) method for the direct determination of cadmium at subnanomolar levels in saline waters based on metal complexation with 2-acetylpyridine salicyloylhydrazone (APSH) and subsequent adsorptive deposition onto a hanging mercury drop electrode (HMDE) is presented. A study strategy based on experimental designs has been followed. Operating conditions were improved with exploratory (Plackett–Burman) and surface response (central composite) experimental designs, involving several chemical and instrumental parameters (pH, ligand concentration, pulse amplitude, time interval for voltage step, voltage step, deposition potential and deposition time). Analytical parameters as repeatability, linearity and accuracy were also investigated and a detection limit (DL) of 0.06 nM was achieved which could be lowered by extending the adsorption time. The interference of other metals and major salts present in seawater was also studied. The method was validated with reference water samples: NIST-SRM 1643d and BCR-CRM 505, showing good concordance with the certified values.