title: Direct determination of cadmium and lead in pharmaceutical ingredients using anodic stripping voltammetry in aqueous and DMSO/water solutions.
abstract: A new electrochemical method has been developed to detect and quantify the elemental impurities, cadmium(II) (Cd(2+)) and lead(II) (Pb(2+)), either simultaneously or individually in pharmaceutical matrices. The electro-analytical approach, involving the use of anodic stripping voltammetry (ASV) on an unmodified glassy carbon electrode, was performed in both aqueous and in a 95/5 dimethyl sulfoxide (DMSO)/water solutions, without acid digestion or dry ashing to remove organic matrices. Limits of detection (LODs) in the μg L(-1) [or parts per billion (ppb), mass/volume] range were obtained for both heavy metals - in the presence and absence of representative pharmaceutical components. To the best of our knowledge, the work demonstrates the first analysis of heavy metals in DMSO/water solutions through ASV. The strong reproducibility and stability of the sensing platform, as well as obviation of sample pretreatment show the promise of utilizing ASV as a sensitive, robust, and inexpensive alternative to inductively-coupled-plasma (ICP)-based approaches for the analysis of elemental impurities in, e.g., pharmaceutical-related matrices.
authors.affiliation: Department of Chemistry, University of Tennessee, Knoxville, TN 37996, USA.
authors.forename: Samuel M
authors.initials: SM
authors.lastname: Rosolina
authors.affiliation: Department of Chemistry, University of Tennessee, Knoxville, TN 37996, USA.
authors.forename: James Q
authors.initials: JQ
authors.lastname: Chambers
authors.affiliation: Pfizer, Inc., Analytical Research and Development, PharmaTherapeutics Pharmaceutical Sciences, Groton, CT 06340, USA.
authors.forename: Carlos W
authors.initials: CW
authors.lastname: Lee
authors.affiliation: Department of Chemistry, University of Tennessee, Knoxville, TN 37996, USA. Electronic address: xue@utk.edu.
authors.forename: Zi-Ling
authors.initials: ZL
authors.lastname: Xue
mesh_terms: D002104:Cadmium / Q000032:analysis*; D002110:Caffeine / Q000737:chemistry; D004121:Dimethyl Sulfoxide / Q000737:chemistry*; D055664:Electrochemical Techniques; D004566:Electrodes; D007785:Lactose / Q000737:chemistry; D007854:Lead / Q000032:analysis*; D057230:Limit of Detection; D019216:Metals, Heavy / Q000032:analysis; D004364:Pharmaceutical Preparations / Q000737:chemistry*; D015203:Reproducibility of Results; D014867:Water / Q000737:chemistry*
chemical_list: D019216:Metals, Heavy; D004364:Pharmaceutical Preparations; D002104:Cadmium; D014867:Water; D007854:Lead; D002110:Caffeine; D007785:Lactose; D004121:Dimethyl Sulfoxide
keywords: Anodic stripping voltammetry; Cadmium; DMSO solutions; Lead; Pharmaceutical ingredients/excipients; Unmodified glassy C electrode