title: An efficient approach to designing and optimizing the analysis of Ni(II) by AdCSV in seawater.
abstract: A highly sensitive voltammetric method was developed for the determination of nickel in seawater at nanomolar concentrations. The measurement is based on the differential pulse cathodic adsorptive stripping of Ni(II) complexed with pyridoxal salicyloylhydrazone at a hanging mercury drop electrode. Optimal conditions were found following a two-step study strategy based on a Plackett Burman design and subsequently a modified simplex method. They were: deposition potential -0.8 V; deposition time 120 s; differential pulse scan mode; pulse amplitude -0.07 V; pulse time 0.04 s; voltage step 0.017 V; time interval for voltage step 0.05 s; supporting electrolyte ammonium chloride/ammonia (0.08 M, pH=8.9) and concentration of PSH 5.32 × 10(-6)M. The response of the system was found to be linear in a range of Ni concentrations from 0 to 306.7 × 10(-9)M. The detection limit was found to be 0.04 × 10(-9)M of Ni(II). The precision of the method was 1.4% for 3.4×10(-8)M of Ni(II) and 1.48% for the blank at a significance level of 95% (n=9). The method was free from interferences of inorganic salts and trace metals at usual concentrations in seawater. The application to seawater was demonstrated by analysis of CRM 505 and LGC 6016 certified reference estuarine water and real seawater samples from Tangier Bay (Morocco).
authors.affiliation: Department of Analytical Chemistry, Faculty of Science, University of Cádiz, Campus Río San Pedro, 11510, Puerto Real, Cádiz, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Aouarram
authors.forename: M D
authors.initials: MD
authors.lastname: Galindo-Riaño
authors.forename: M
authors.initials: M
authors.lastname: García-Vargas
authors.forename: M
authors.initials: M
authors.lastname: Stitou
authors.forename: F
authors.initials: F
authors.lastname: El Yousfi
authors.forename: E
authors.initials: E
authors.lastname: Espada-Bellido
mesh_terms: D000327:Adsorption; D055664:Electrochemical Techniques / Q000295:instrumentation / Q000379:methods*; D004566:Electrodes; D007202:Indicators and Reagents; D008024:Ligands; D057230:Limit of Detection; D008628:Mercury / Q000737:chemistry; D009018:Morocco; D009532:Nickel / Q000032:analysis*; D012015:Reference Standards; D012107:Research Design; D012623:Seawater / Q000032:analysis* / Q000737:chemistry; D013056:Spectrophotometry, Ultraviolet; D014131:Trace Elements / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D007202:Indicators and Reagents; D008024:Ligands; D014131:Trace Elements; D014874:Water Pollutants, Chemical; D009532:Nickel; D008628:Mercury