title: Trace measurements of the antineoplastic agent methotrexate by adsorptive stripping voltammetry.
abstract: An extremely sensitive voltammetric method is presented for trace measurement of the cancer chemotherapy drug methotrexate. The method is based on controlled adsorptive preconcentration of methotrexate on the hanging mercury-drop electrode, followed by voltammetric determination of the surface species. Cyclic voltammetry was used to explore the interfacial behaviour. The adsorptive stripping response was evaluated with respect to preconcentration time and potential, pH, concentration dependence, stripping mode, possible interferences, and other variables. The detection limit found was 2 x 10(-9)M (5-min preconcentration), the response was linear, and the relative standard deviation (at the 1.6 x 10(-7)M level) 2.2%. Sensitive adsorptive stripping measurements were also obtained by use of a carbon-paste disk electrode. Applicability to urine analysis is illustrated.
authors.affiliation: Department of Chemistry, New Mexico State University, Las Cruces, NM 88003, U.S.A.
authors.forename: J
authors.initials: J
authors.lastname: Wang
authors.forename: P
authors.initials: P
authors.lastname: Tuzhi
authors.forename: M S
authors.initials: MS
authors.lastname: Lin
authors.forename: T
authors.initials: T
authors.lastname: Tapia