title: A new sensitive electrochemical method for the determination of vanadium(IV) and vanadium(V) in Benfield sample.
abstract: Vanadium(IV) and vanadium(V) can be determined by using differential pulse cathodic stripping voltammetry technique (DPCSV). Cupferron (ammonium N-nitrosophenylhydroxylamine) was used as ligand to form complex compounds with vanadium ions in Britton-Robinson buffer (BRB) solution. At concentration lower than 1.0×10(-6) M, both V(IV) and V(V) cupferron complexes showed a single cathodic peak at -0.576 V in BRB of pH 4; thus V(IV) and V(V) ions cannot be differentiated at low concentration. However, the ionic species of vanadium can be differentiated at high concentration in the presence of cupferron. Parameters including pH of BRB solution, initial potential and accumulation potential were optimized. Under the optimized parameters, the limit of detection (LOD) was 0.09 nM, and the peak current was linear in the concentration range 0.01-0.9 µM total vanadium ions. The determination of V(IV) and V(V) ions was carried out at higher concentration in the sample using calibration plot method. At higher concentration range of 10-60 µM V(IV) and V(V) ions were determined with LOD of 1.2 and 1.1 µM, respectively. The developed method was successfully applied to 10,00,000 fold diluted Benfield sample and 0.6227 M total vanadium ions were determined. The determination of V(IV) and V(V) ions were also successfully carried out in artificial sample as well as Benfield sample (dilution factor, 10,000). The concentration of V(IV) and V(V) ions was 22.52 µM and 38.91 µM, respectively, giving total vanadium concentration of 0.6143 M in Benfield sample.
authors.affiliation: Institute of Environmental & Water Resource Management (IPASA), Universiti Teknologi Malaysia, Skudai, Johor, Malaysia. Electronic address: munawar@utm.my.
authors.forename: Munawar Saeed
authors.initials: MS
authors.lastname: Qureshi
authors.affiliation: Institute of Environmental & Water Resource Management (IPASA), Universiti Teknologi Malaysia, Skudai, Johor, Malaysia.
authors.forename: Abdull Rahim bin
authors.initials: AR
authors.lastname: Mohd Yusoff
authors.affiliation: Department of Chemistry, University of Science and Technology, Bannu 28100, Khyber Pakhtunkhwa, Pakistan; School of Chemistry, Monash University, Clayton Campus 3800, Melbourne, VIC, Australia. Electronic address: afzalnm@yahoo.com.
authors.forename: Afzal
authors.initials: A
authors.lastname: Shah
authors.affiliation: Department of Chemistry, College of Science, King Saud University, Riyadh 11451, Saudi Arabia.
authors.forename: Ayman
authors.initials: A
authors.lastname: Nafady
authors.affiliation: National Center of Excellence in Analytical Chemistry, University of Sindh, Jamshoro, Pakistan.
authors.lastname: Sirajuddin
keywords: Artificial sample; Benfield sample; Britton–Robinson; Cupferron; Differential pulse cathodic stripping voltammetry