title: Determination of trace elements in lithium niobate crystals by solid sampling and solution-based spectrometry methods.
abstract: Solid sampling (SS) graphite furnace atomic absorption spectrometry (GFAAS) and solution-based (SB) methods of GFAAS, flame atomic absorption spectrometry (FAAS), inductively coupled plasma optical emission spectrometry (ICP-OES) and inductively coupled plasma mass spectrometry (ICP-MS) were elaborated and/or optimized for the determination of Cr, Fe and Mn trace elements used as dopants in lithium niobate optical crystals. The calibration of the SS-GFAAS analysis was possible with the application of the three-point-estimation standard addition method, while the SB methods were mostly calibrated against matrix-matched and/or acidic standards. Spectral and non-spectral interferences were studied in SB-GFAAS after digestion of the samples. The SS-GFAAS method required the use of less sensitive spectral lines of the analytes and a higher internal furnace gas (Ar) flow rate to decrease the sensitivity for crystal samples of higher (doped) analyte content. The chemical forms of the matrix produced at various stages of the graphite furnace heating cycle, dispensed either as a solid sample or a solution (after digestion), were studied by means of the X-ray near-edge absorption structure (XANES). These results revealed that the solid matrix vaporized/deposited in the graphite furnace is mostly present in the metallic form, while the dry residue from the solution form mostly vaporized/deposited as the oxide of niobium.
authors.affiliation: Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, Budapest, Hungary. bencs.laszlo@wigner.mta.hu
authors.forename: László
authors.initials: L
authors.lastname: Bencs
authors.forename: Krisztina
authors.initials: K
authors.lastname: György
authors.forename: Márta
authors.initials: M
authors.lastname: Kardos
authors.forename: János
authors.initials: J
authors.lastname: Osán
authors.forename: Bálint
authors.initials: B
authors.lastname: Alföldy
authors.forename: Imre
authors.initials: I
authors.lastname: Varga
authors.forename: Zsolt
authors.initials: Z
authors.lastname: Ajtony
authors.forename: Norbert
authors.initials: N
authors.lastname: Szoboszlai
authors.forename: Zsolt
authors.initials: Z
authors.lastname: Stefánka
authors.forename: Eva
authors.initials: E
authors.lastname: Széles
authors.forename: László
authors.initials: L
authors.lastname: Kovács