title: Focused ultrasound versus microwave digestion for the determination of lead in must by electrothermal-atomic absorption spectrometry.
abstract: The content of metals at the different stages of the winemaking process is of great concern because of legal and wine quality reasons. In the present work, we have developed a new fast procedure for metal extraction from must based on focused ultrasound with HNO3 and H2O2, with which microwave digestion of the must is not necessary. Lead was used as a model element to achieve the optimum combination of reagents in order to achieve total extraction. Results were compared with those obtained after microwave digestion of the samples. In addition, conventional and fast programs in conjunction with different matrix modifiers were studied. The method requires few sample mass (ca 0.5 g) and few reagents in low volume (HNO3 50 microL and H2O2 100 microL). The total sample treatment time is only 60 s.
authors.affiliation: Centro de Quimica Estrutural, Instituto Superior Técnico de Lisboa, Avda Rovisco Pais, s/n, 1049-001, Lisbon, Portugal. jlcapelom@ist.utl.pt
authors.forename: Jóse L
authors.initials: JL
authors.lastname: Capelo
authors.forename: Sofia
authors.initials: S
authors.lastname: Catarino
authors.forename: António S
authors.initials: AS
authors.lastname: Curvelo-Garcia
authors.forename: Miguel
authors.initials: M
authors.lastname: Vaiâo
mesh_terms: D002138:Calibration; D007202:Indicators and Reagents; D007854:Lead / Q000032:analysis*; D008872:Microwaves; D012015:Reference Standards; D015203:Reproducibility of Results; D012996:Solutions; D013054:Spectrophotometry, Atomic; D014465:Ultrasonics; D014920:Wine / Q000032:analysis*
chemical_list: D007202:Indicators and Reagents; D012996:Solutions; D007854:Lead