Instant Notes: Analytical Chemistry

353 Pages·2005·2.2 MB·English

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Analytical Chemistry
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ii Section K – Lipid metabolism
The INSTANT NOTES series
Series editor
B.D. Hames
School of Biochemistry and Molecular Biology, University of Leeds, Leeds, UK
Animal Biology
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The INSTANT NOTES Chemistry series
Consulting editor: Howard Stanbury
Analytical Chemistry
Inorganic Chemistry
Medicinal Chemistry
Organic Chemistry
Physical Chemistry
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Analytical Chemistry
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D. Kealey
School of Biological and Chemical Sciences
Birkbeck College, University of London, UK
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Department of Chemistry
University of Surrey, Guildford, UK
and
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Oakland Analytical Services,
Farnham, UK
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© BIOS Scientific Publishers Limited, 2002
First published 2002 (ISBN 1 85996 189 4)
This edition published in the Taylor & Francis e-Library, 2005.
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A CIP catalogue record for this book is available from the British Library.
ISBN 0-203-64544-8 Master e-book ISBN
ISBN 0-203-68109-6 (Adobe eReader Format)
ISBN 1 85996 189 4 (Print Edition)
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C
ONTENTS
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Abbreviations vii
Preface ix
Section A – The nature and scope of analytical chemistry 1
0111 A1 Analytical chemistry, its functions and applications 1
A2 Analytical problems and procedures 3
A3 Analytical techniques and methods 5
A4 Sampling and sample handling 10
A5 Calibration and standards 15
A6 Quality in analytical laboratories 18
Section B − Assessment of data 21
B1 Errors in analytical measurements 21
B2 Assessment of accuracy and precision 26
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B3 Significance testing 34
B4 Calibration and linear regression 41
B5 Quality control and chemometrics 49
Section C − Analytical reactions in solution 55
C1 Solution equilibria 55
C2 Electrochemical reactions 61
C3 Potentiometry 66
C4 pH and its control 74
0111 C5 Titrimetry I: acid–base titrations 80
C6 Complexation, solubility and redox equilibria 85
C7 Titrimetry II: complexation, precipitation and redox
titrations 90
C8 Gravimetry 95
C9 Voltammetry and amperometry 98
C10 Conductimetry 104
Section D − Separation techniques 109
D1 Solvent and solid-phase extraction 109
0111 D2 Principles of chromatography 119
D3 Thin-layer chromatography 131
D4 Gas chromatography: principles and instrumentation 137
D5 Gas chromatography: procedures and applications 149
D6 High-performance liquid chromatography: principles
and instrumentation 155
D7 High-performance liquid chromatography: modes,
procedures and applications 166
D8 Electrophoresis and electrochromatography: principles
and instrumentation 174
0 D9 Electrophoresis and electrochromatography: modes,
11 procedures and applications 182
vi Contents
Section E − Spectrometric techniques 189
E1 Electromagnetic radiation and energy levels 189
E2 Atomic and molecular spectrometry 195
E3 Spectrometric instrumentation 201
E4 Flame atomic emission spectrometry 206
E5 Inductively coupled plasma spectrometry 209
E6 X-ray emission spectrometry 214
E7 Atomic absorption and atomic fluorescence spectrometry 218
E8 Ultraviolet and visible molecular spectrometry:
principles and instrumentation 223
E9 Ultraviolet and visible molecular spectrometry:
applications 228
E10 Infrared and Raman spectrometry: principles and
instrumentation 233
E11 Infrared and Raman spectrometry: applications 242
E12 Nuclear magnetic resonance spectrometry: principles
and instrumentation 248
E13 Nuclear magnetic resonance spectrometry: interpretation
of proton and carbon-13 spectra 261
E14 Mass spectrometry 270
Section F − Combined techniques 283
F1 Advantages of combined techniques 283
F2 Sample identification using multiple spectrometric
techniques data 285
F3 Gas chromatography–mass spectrometry 294
F4 Gas chromatography–infrared spectrometry 298
F5 Liquid chromatography–mass spectrometry 302
Section G − Thermal methods 305
G1 Thermogravimetry 305
G2 Differential thermal analysis and differential scanning
calorimetry 311
G3 Thermomechanical analysis 316
G4 Evolved gas analysis 320
Section H – Sensors, automation and computing 323
H1 Chemical sensors and biosensors 323
H2 Automated procedures 328
H3 Computer control and data collection 331
H4 Data enhancement and databases 333
Further reading 337
Index 339
A
BBREVIATIONS
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AAS atomic absorption spectrometry ICP-MS ICP-mass spectrometry
ADC analog-to-digital converter IEC ion-exchange chromatography
AFS atomic fluorescence spectrometry ISE ion-selective electrode
ANOVA analysis of variance LVDT linear variable differential
ATR attenuated total reflectance transformer
0111 BPC bonded-phase chromatography MEKC micellar electrokinetic
CC chiral chromatography chromatography
CGE capillary gel electrophoresis MIR multiple internal reflectance
CI confidence interval MS mass spectrometry
CIEF capillary isoelectric focusing NIR near infrared
CL confidence limits NMR nuclear-magnetic resonance
CPU central processing unit NPD nitrogen-phosphorus detector
CRM certified reference material PAH polycyclic aromatic hydrocarbons
CZE capillary zone electrophoresis PC paper chromatography
DAC digital-to-analog converter PCA principal component analysis
0111 DAD diode array detector PCR principal component regression
DMA dynamic mechanical analysis PDMS polydimethylsiloxane
DME dropping mercury electrode PLS partial least squares
DSC differential scanning calorimetry QA quality assurance
DTA differential thermal analysis QC quality control
DTG derivative thermogravimetry RAM random access memory
DVM digital voltmeter RF radiofrequency
ECD electron-capture detector RI refractive index
EDAX energy dispersive analysis ROM read only memory
of X-rays RMM relative molecular mass
0111 EDTA ethylenediaminetetraacetic acid SCE saturated calomel electrode
EGA evolved gas analysis SDS sodium dodecyl sulfate
FA factor analysis SDS-PAGE SDS-polyacrylamide gel
FAES flame atomic emission electrophoresis
spectometry SE solvent extraction
FFT fast Fourier transform SEC size-exclusion chromatography
FID flame ionization detector SHE standard hydrogen electrode
or free induction decay SIM selected ion monitoring
GC gas chromatography SPE solid phase extraction
GLC gas liquid chromatography SPME solid phase microextraction
0111 GSC gas solid chromatography SRM standard reference material
HATR horizontal attenuated total TCD thermal conductivity detector
reflectance TG thermogravimetry
HPLC high-performance liquid TIC total ion current
chromatography TISAB total ionic strength adjustment
IC ion chromatography buffer
ICP inductively coupled plasma TLC thin-layer chromatography
ICP-AES ICP-atomic emission spectrometry TMA thermomechanical analysis
ICP-OES ICP-optical emission spectrometry
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P
REFACE
Analytical chemists and others in many disciplines frequently ask questions such as: What is this
substance?; How concentrated is this solution?; What is the structure of this molecule? The answers to
these and many other similar questions are provided by the techniques and methods of analytical
chemistry. They are common to a wide range of activities, and the demand for analytical data of a
chemical nature is steadily growing. Geologists, biologists, environmental and materials scientists,
physicists, pharmacists, clinicians and engineers may all find it necessary to use or rely on some of the
techniques of analysis described in this book.
If we look back some forty or fifty years, chemical analysis concentrated on perhaps three main areas:
qualitative testing, quantitative determinations, particularly by ‘classical’ techniques such as titrimetry
and gravimetry, and structural analysis by procedures requiring laborious and time-consuming calcu-
lations. The analytical chemist of today has an armoury of instrumental techniques, automated systems
and computers which enable analytical measurements to be made more easily, more quickly and more
accurately.
However, pitfalls still exist for the unwary! Unless the analytical chemist has a thorough understand-
ing of the principles, practice and limitations of each technique he/she employs, results may be inaccu-
rate, ambiguous, misleading or invalid. From many years of stressing the importance of following
appropriate analytical procedures to a large number of students of widely differing abilities, backgrounds
and degrees of enthusiasm, the authors have compiled an up-to-date, unified approach to the study of
analytical chemistry and its applications. Surveys of the day-to-day operations of many industrial and
other analytical laboratories in the UK, Europe and the USA have shown which techniques are the most
widely used, and which are of such limited application that extensive coverage at this level would be
inappropriate. The text therefore includes analytical techniques commonly used by most analytical
laboratories at this time. It is intended both to complement those on inorganic, organic and physical
chemistry in the Instant Notesseries, and to offer to students in chemistry and other disciplines some guid-
ance on the use of analytical techniques where they are relevant to their work. We have not given extended
accounts of complex or more specialized analytical techniques, which might be studied beyond first- and
second-year courses. Nevertheless, the material should be useful as an overview of the subject for those
studying at a more advanced level or working in analytical laboratories, and for revision purposes.
The layout of the book has been determined by the series format and by the requirements of the
overall analytical process. Regardless of the discipline from which the need for chemical analysis arises,
common questions must be asked:
● How should a representative sample be obtained?
● What is to be determined and with what quantitative precision?
● What other components are present and will they interfere with the analytical measurements?
● How much material is available for analysis, and how many samples are to be analyzed?
● What instrumentation is to be used?
● How reliable is the data generated?
These and related questions are considered in Sections A and B.
Most of the subsequent sections provide notes on the principles, instrumentation and applications of
both individual and groups of techniques. Where suitable supplementary texts exist, reference is made
to them, and some suggestions on consulting the primary literature are made.
We have assumed a background roughly equivalent to UK A-level chemistry or a US general
chemistry course. Some simplification of mathematical treatments has been made; for example, in the
sections on statistics, and on the theoretical basis of the various techniques. However, the texts listed
under Further Reading give more comprehensive accounts and further examples of applications.