title: Fluorimetric determination of ultratraces of lead by ion-pair extraction with cryptand 2.2.1 and eosin.
abstract: A spectrofluorimetric study of the extraction of lead into 1,2-dichloroethane, as an ion-pair formed between the cryptand 2.2.1-lead complex and the eosinate counter-ion is described. Optimum conditions for the extraction have been established and a new spectrofluorimetric determination of ultratraces of lead is proposed (detection limit 0.8 ng/ml; relative standard deviation 2.4% at the 60 ng/ml level). The metal:ligand:counter-ion molecular ratio in the extracted mononuclear ion-pair is 1:1:1. The equilibrium constants involved in the extraction have been estimated and refined by the Letagrop-DISTR program.
authors.affiliation: Departamento de Química Física y Analítica, Facultad de Química, Universidad de Oviedo, Oviedo, Spain.
authors.forename: D B
authors.initials: DB
authors.lastname: Gomis
authors.forename: P A
authors.initials: PA
authors.lastname: Abrodo
authors.forename: A M
authors.initials: AM
authors.lastname: Lobo
authors.forename: A S
authors.initials: AS
authors.lastname: Medel