High-Resolution Continuum Source AAS: The Better Way to Do Atomic Absorption Spectrometry

310 Pages·2005·7.9 MB·English

by  Bernhard Welz

High-Resolution
Continuum Source AAS
The Better Way to Do Atomic Absorption
Spectrometry
Bernhard Welz,Helmut Becker-Ross,
Stefan Florek,Uwe Heitmann
WILEY-VCH Verlag GmbH & Co.KGaA

High-Resolution
Continuum Source AAS
B.Welz,H.Becker-Ross,
S.Florek,U.Heitmann
Further Titles of Interest:
J.A.C.Broekaert
Analytical Atomic Spectrometry with Flames
and Plasmas
2nd Edition
2005,ISBN 3-527-31282-X
E.Merian,M.Anke,M.Ihnat,M.Stoeppler
Elements and their Compounds in the Environment
Occurrence,Analysis and Biological Relevance
3 Volumes,2nd Edition
2004,ISBN 3-527-30459-2
J.Nölte
ICP Emission Spectrometry
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B.Welz,M.Sperling
Atomic Absorption Spectrometry
3rd Edition
1999,ISBN 3-527-28571-7
High-Resolution
Continuum Source AAS
The Better Way to Do Atomic Absorption
Spectrometry
Bernhard Welz,Helmut Becker-Ross,
Stefan Florek,Uwe Heitmann
WILEY-VCH Verlag GmbH & Co.KGaA
Authors All books published by Wiley-VCH are carefully
produced.Nevertheless,authors,and publisher do
not warrant the information contained in these
Prof.Dr.Bernhard Welz
books,including this book,to be free of errors.
Departamento de Química
Universidade Federal de Santa Catarina Readers are advised to keep in mind that state-
88040-900 Florianópolis – SC ments,data,illustrations,procedural details or
Brazil other items may inadvertently be inaccurate.
Dr.Helmut Becker-Ross
Library of Congress Card No.:applied for
ISAS – Institute for Analytical Sciences,
Department Berlin British Library Cataloging-in-Publication Data:
ISAS – Institute for Analytical Sciences, A catalogue record for this book is available from
Department Berlin the British Library
Albert-Einstein-Strasse 9
12489 Berlin
Bibliographic information published by
Germany
Die Deutsche Bibliothek
Dr.Stefan Florek Die Deutsche Bibliothek lists this publication
ISAS – Institute for Analytical Sciences, in the Deutsche Nationalbibliografie;detailed
Department Berlin
bibliographic data is available in the
Albert-Einstein-Strasse 9
Internet at <http://dnb.ddb.de>.
12489 Berlin
Germany
Dr.Uwe Heitmann © 2005 WILEY-VCH Verlag GmbH & Co.
ISAS – Institute for Analytical Sciences,
KGaA,Weinheim
Department Berlin
Albert-Einstein-Strasse 9
12489 Berlin All rights reserved (including those of translation
Germany into other languages).No part of this book may
be reproduced in any form – nor transmitted or
translated into machine language without written
permission from the publishers.Registered
names,trademarks,etc.used in this book,even
when not specifically marked as such,are not to
be considered unprotected by law.
Printed in the Federal Republic of Germany
Printed on acid-free paper
Printing Druckhaus Darmstadt GmbH,
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Bookbinding Litges & Dopf Buchbinderei
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ISBN-13: 978- 3-527-30736-4
ISBN-10: 3-527-30736-2
Preface
Conventionallinesourceatomicabsorptionspectrometry(LSAAS)cannowadaysbecon-
sideredanestablishedtechniqueinthepositivesenseoftheterm,i.e.itiswidelyused,and
no dramatic improvements are expected in the foreseeable future. The state-of-the-art of
conventional LSAAS is fully described in the book of Welz and Sperling [150], and its
content may well be valid for another decade or two. The only progress will be in the
developmentofnewapplications,butthisfieldistodayfullycoveredbyavarietyofdata
banks, which are easily accessible through the Internet, so that this increase in literature
onapplicationsdoesnotjustifyaneweditionofthisbook.
TheonlyrealprogressinthefieldofAAS,intheopinionoftheauthors,isinthedi-
rectionofhigh-resolutioncontinuumsourceAAS(HR-CSAAS),whichwillundoubtedly
bethefutureofthistechnique.Forthisreasonwethoughtitwouldbemuchmoreuseful
to write a new book about HR-CSAAS, which might be considered a ‘Volume 2’ or a
‘Supplement’ of the above basic book on AAS. This means we expect the reader of this
booktobeawareofthebasicconceptsofAAS,whichisfullycoveredinReference[150],
andsowehavedeliberatelyavoidedrepeatingthingsinthisbookthathavebeendescribed
in the former one. For example, neither the different atomizers used in AAS, i.e. flame,
graphite furnace or quartz tube atomizers, nor the atomization mechanisms or the non-
spectralinterferencesoccurringintheseatomizersarediscussedinthisbook,astheyare
obviouslyidentical.Inessence,onlythenewaspectsanddevelopmentsthatareparticular
toHR-CSAASarediscussedindetail,whereascommonthingsarerepeatedonlywhere
absolutelynecessary.
The content of this book, regarding practical application, has essentially been pro-
duced over a time period of less than two years using prototype instruments, which are
similar, but not identical, to the commercially available instrument. There have been an
impressive number of people, master, doctoral and post-doctoral students, working with
theseprototypes,butobviouslywecanonlygiveexamplesfortheapplicationofthisnew
technique, not a full coverage of all the possibilities. We expect that you, the readers of
this book, who hopefully will be using this exciting new technique, will be contributing
v
Preface
totheexplorationofthepotentialofHR-CSAASsothatthesecondeditionofthisbook
willcontainamuchmorecompletecoverageofyetundiscoveredapplicationpossibilities
ofthisnewtechnique.
This book is an integral part of the professorial dissertation of Uwe Heitmann. He
haswrittenseveralchaptersandwasresponsibleforthepreparationofthefiguresaswell
as for the total arrangement and layout of this book up to the delivery of a ready-for-
pressmanuscript.UweHeitmannhasbeenconcernedwiththeHR-CSAASprojectsince
1994. He was involved in most of the measurements, their evaluation and interpretation.
Moreover, he carried out the setup of the prototype instruments and wrote the in-house
softwarefordataacquisition,signalprocessingandbackgroundcorrection.
Florianópolis,Berlin,December2004 BernhardWelz
HelmutBecker-Ross
StefanFlorek
UweHeitmann
vi
Contents
1. Historical Development of Continuum Source AAS 1
2. Theoretical Concepts 5
2.1 SpectralLineProfiles . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.1.1 NaturalLineWidth . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.1.2 DopplerBroadening . . . . . . . . . . . . . . . . . . . . . . . . 6
2.1.3 CollisionBroadening . . . . . . . . . . . . . . . . . . . . . . . . 7
2.1.4 VoigtProfiles . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.1.5 InstrumentProfile . . . . . . . . . . . . . . . . . . . . . . . . . 11
2.2 AtomicAbsorptionwithaContinuumSource . . . . . . . . . . . . . . . 17
2.2.1 GeneralPrincipleofAbsorption . . . . . . . . . . . . . . . . . . 17
2.2.2 InstrumentEffects . . . . . . . . . . . . . . . . . . . . . . . . . 18
2.3 StructureofMolecularSpectra . . . . . . . . . . . . . . . . . . . . . . . 24
2.3.1 ElectronicTransitions . . . . . . . . . . . . . . . . . . . . . . . 24
2.3.2 VibrationalSpectra . . . . . . . . . . . . . . . . . . . . . . . . . 26
2.3.3 RotationalSpectra . . . . . . . . . . . . . . . . . . . . . . . . . 28
2.3.4 DissociationContinua . . . . . . . . . . . . . . . . . . . . . . . 30
3. Instrumentation for HR-CSAAS 31
3.1 RadiationSource . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
3.2 ResearchSpectrometerswithActiveWavelengthStabilization . . . . . . 34
3.2.1 EchelleGrating . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
3.2.2 SequentialSpectrometer . . . . . . . . . . . . . . . . . . . . . . 37
3.2.3 SimultaneousSpectrometer . . . . . . . . . . . . . . . . . . . . 46
3.3 Detector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
3.4 ThecontrAA300fromAnalytikJenaAG . . . . . . . . . . . . . . . . . 53
vii