title: On-line preconcentration/determination of lead in Ilex paraguariensis samples (mate tea) using polyurethane foam as filter and USN-ICP-OES.
abstract: The present paper proposes an on-line preconcentration procedure for lead determination in Ilex paraguariensis (St. Hilaire) samples by ultrasonic nebulization associated to inductively coupled plasma optical emission spectrometry (USN-ICP-OES). It is based on the precipitation of lead(II) ion on a minicolumn packed with polyurethane foam using 2-(5-bromo-2-pyridilazo)-5-diethylaminophenol (5-Br-PADAP) as precipitating reagent. The collected analyte precipitate was quantitatively eluted from the minicolumn with 20% (v/v) nitric acid. An enhancement factor of 225-fold was obtained (15 for USN and 15 for preconcentration). The detection limit (DL) value for the preconcentration of 10.0 ml of sample was 40.0 ng/l. The relative standard deviation (R.S.D.) was 3.0% for a Pb concentration of 1 microg/l, calculated from the peak heights obtained. The calibration graph using the preconcentration system for lead was linear with a correlation coefficient of 0.9997, at levels near the detection limits up to at least 100 microg/l. The preconcentration procedure was successfully applied to the determination of lead in mate tea samples.
authors.affiliation: Department of Analytical Chemistry, Faculty of Biochemistry, Chemistry and Pharmacy, National University of Tucumán, Ayacucho 491, 4000 Tucumán, Argentina.
authors.forename: P F
authors.initials: PF
authors.lastname: Marchisio
authors.forename: A
authors.initials: A
authors.lastname: Sales
authors.forename: S
authors.initials: S
authors.lastname: Cerutti
authors.forename: E
authors.initials: E
authors.lastname: Marchevski
authors.forename: L D
authors.initials: LD
authors.lastname: Martinez
mesh_terms: D001628:Beverages / Q000032:analysis*; D002138:Calibration; D011232:Chemical Precipitation; D005374:Filtration / Q000295:instrumentation* / Q000379:methods*; D005506:Food Contamination / Q000032:analysis*; D006863:Hydrogen-Ion Concentration; D030019:Ilex paraguariensis / Q000737:chemistry*; D007854:Lead / Q000032:analysis*; D008422:Materials Testing; D011140:Polyurethanes; D013054:Spectrophotometry, Atomic / Q000379:methods
chemical_list: D011140:Polyurethanes; D007854:Lead