CONTENTS

Chapter 1 The Nature of Analytical Chemistry 21A The Roleof Analytical Chemistry 31B Quantitative Analytical Methods 41C A TypicalQuantitative Analysis 51D An Integral Rolefor ChemicalAnalysis:

FeedbackControl Systems 10Feature1-1 Deer Kill: A CaseStudy Illustrating the Use

of Analytical Chemistry to Solvea Problemin Toxicology 12

PART I Tools of Analytical Chemistry 17

A Conversation with Richard N. Zare 18

Chapter 2 Chemicals, Apparatus, and Unit Operationsof Analytical Chemistry 20

2A Selecting and Handling Reagents and OtherChemicals 21

2B Cleaning and Marking of Laboratory Ware 22

2C Evaporating Liquids 23

2D Measuring Mass 23

2E Equipment and Manipulations Associated withWeighing 30

2F Filtration and Ignition of Solids 33

2G Measuring Volume 39

2H Calibrating Volumetric Glassware 48

21 The Laboratory Notebook 51

2J Safety in the Laboratory 52

Chapter 3 Using Spreadsheets in AnalyticalChemistry 54

3A KeepingRecordsand Making Calculations:SpreadsheetExercise1 55

3B CalculatingMolar MassesUsing Excel:SpreadsheetExercise2 60

Chapter 4 Calculations Used in AnalyticalChemistry 71

4A Some Important Units of Measurement 71Feature 4-1 Atomic Mass Units and the Mole 734B Solutions and Their Concentrations 76

4C ChemicalStoichiometry 83

Chapter 5 Errors in Chemical Analyses 90SA Some Important Terms 925B SystematicErrors 95

Chapter 6 Random Errors in Chemical Analysis 1056A The Nature of Random Errors 105

Feature 6-1 Flipping Coins: A Student Activity toIllustrate a Normal Distribution 109

6B Statistical Treatment of Random Error 110

Feature 6-2 Calculating the Areas under the GaussianCurve 113

Feature 6-3 The Significance of the Number of Degreesof Freedom 116

Feature 6-4 Equation for Calculating the PooledStandard Deviation 124

6C Standard Deviation of Calculated Results 127

6D Reporting Computed Data 133

Chapter 7 Statistical Data Treatment andEvaluation 142

7A ConfidenceIntervals 143

Feature 7-1 Breath Alcohol Analyzers 1487B Statistical Aids to HypothesisTesting 1497C Analysisof Variance 1607D Detection of GrossErrors 167

Chapter 8 Sampling, Standardization,and Calibration 175

8A Analytical Samples and Methods 175

8B Sampling and Sample Handling 178

Feature 8-1 Lab-on-a-Chip 1918C Standardization and Calibration 192

Feature 8-2 A Comparison Method for AflatoxinsFeature 8-3 Multivariate Calibration 208

8D Figures of Merit for Analytical Methods 214

192

PART II Chemical Equilibria 225

A Conversation with Sylvia Daunert 226

Chapter 9 Aqueous Solutions and ChemicalEquilibria 228

v

vi Contents

9A The Chemical Compositions of AqueousSolutions 228

9B Chemical Equilibrium 233Feature 9-1 Stepwise and Overall Formation Constants

for Complex Ions 236Feature 9-2 Why[H2O] Does Not Appear in Equilibrium-

Constant Expressions for AqueousSolutions 237

Feature 9-3 Relative Strengths of Conjugate Acid/BasePairs 244

Feature 9-4 The Method of SuccessiveApproximations 248

9C Buffer Solutions 251Feature 9-5 The Henderson-Hasselbalch

Equation 252Feature 9-6 Acid Rain and the Buffer Capacity of

Lakes 259

Chapter 10 Effect of Electrolytes on ChemicalEquilibria 267

lOA The Effect of Electrolytes on ChemicalEquilibria 267

lOB Activity Coefficients 271Feature 10-1 Mean Activity Coefficients 274

Chapter 11 Solving Equilibrium Calculations forComplex Systems 281

11A Solving Multiple-Equilibrium Problems by aSystematic Method 282

11B Calculating Solubilities by the SystematicMethod 287

Feature 11-1 Algebraic Expressions Needed toCalculate the Solubility of CaC2O4 inWater 294

11C Separation of Ions by Control of the Concentrationof the Precipitating Agent 300

Feature 11-2 Immunoassay: Equilibria in the SpecificDetermination of Drugs 304

PART III Classical Methods of Analysis 311

A Conversationwith Larry R. Faulkner 312

Chapter 12 Gravimetric Methods of Analysis 31412A PrecipitationGravimetry 315Feature 12-1 SpecificSurfaceArea of Colloids 32212B Calculationof Resultsfrom GravimetricData 32612C Applicationsof GravimetricMethods 329

Chapter 13 Titrimetric Methods; PrecipitationTitrimetry 337

13A SomeTermsUsed in VolumericTitrimetry13B Standard Solutions 340

338

13C Volumetric Calculations 341

Feature 13-1 Another Approach toExample 13-6(a) 346

Feature 13-2 Rounding the Answer toExample 13-7 347

13D Gravimetric Titrimetry 34913E Titration Curves in Titrimetric Methods 350

13F Precipitation Titrimetry 353Feature 13-3 Calculating the Concentration of Indicator

Solutions 361

Chapter 14 Principles of Neutralization Titrations 36814A Solutions and Indicators for Acid/Base

Titrations 368

14B Titration of Strong Acids and Strong Bases 372Feature 14-1 Using the Charge-Balance Equation to

Construct Titration Curves 375

Feature 14-2 How Many Significant Figures ShouldWe Retain in Titration CurveCalculations? 378

14C Titration Curves for Weak Acids 378

Feature 14-3 Determining Dissociation Constants forWeak Acids and Bases 381

14D Titration Curves for Weak Bases 383

Feature 14-4 Determining the pK Values for AminoAcids 385

14E The Composition of Solutions During Acid/BaseTitrations 387

Feature 14-5 Locating Titration End Points from pHMeasurements 388

Chapter 15 Titration Curves for Complex Acid/BaseSystems 395

15A Mixtures of Strong and Weak Acids or Strong andWeak Bases 398

15B Polyfunctional Acids and Bases 39915C Buffer Solutions Involving Polyprotic Acids 40115D Calculation of the pH of Solutions of NaHA 40315E Titration Curves for Polyfunctional Acids 407Feature 15-1 The Dissociation of Sulfuric Acid 41 515F Titration Curves for Polyfunctional Bases 41 615G Titration Curves for Amphiprotic Species 417Feature 15-2 Acid/Base Behavior of Amino Acids 418

15H The Composition of Solutions of a Polyprotic Acidas a Function of pH 419

Feature 15-3 A General Expression for AlphaValues 420

Feature 15-4 Logarithmic Concentration Diagrams 422

Chapter 16 Applications of NeutralizationTitrations 428

16A Reagents for NeutralizationTitrations 429

16B TypicalApplications of NeutralizationTitrations 435

Feature 16-1 Determining Total Serum Protein 435

Feature 16-2 Other Methods for Determining OrganicNitrogen 436

Feature 16-3 Equivalent Weights of Acids andBases 442

Chapter 17 Complexation Reactions and Titrations 449

17A The Formation of Complexes 449Feature 17-1 Calculation of Alpha Values for Metal

Complexes 452

17B Titrations with Inorganic Complexing Agents 455

Feature 17-2 Determination of Hydrogen Cyanide inAcrylonitrile Plant Streams 456

17C Organic Complexing Agents 457

17D Aminocarboxylic Acid Titrations 458

Feature 17-3 Species Present in a Solution of EDTA 459Feature 17-4 EDTA as a Preservative 462

Feature 17-5 EDTA Titration Curves When a Complex-ing Agent Is Present 473

Feature 17-6 How Masking and Demasking Agents CanBe Used to Enhance the Selectivity ofEDTA Titrations 480

Feature 17-7 Test Kits for Water Hardness 482

PART IV 487Electrochemical Methods

A Conversation with Allen J.Bard 488

Chapter 18 Introduction to Electrochemistry 49018A Characterizing Oxidation/Reduction Reactions 490

Feature 18-1 Balancing Redox Equations 49218B Electrochemical Cells 494

Feature 18-2 The Daniell Gravity Cell 49818C Electrode Potentials 499

Feature 18-3 Why We Cannot Measure AbsoluteElectrode Potentials 504

Feature 18-4 Sign Conventions in the OlderLiterature 513

Feature 18-5 Why Are There Two Electrode Potentialsfor Br2 in Table 18-17 515

Chapter 19 Applications of Standard ElectrodePotentials 523

19A CalculatingPotentialsof ElectrochemicalCells 52319B Determining Standard Potentials

Experimentally 53019C Calculating Redox Equilibrium Constants 532Feature 19-1 Biological RedoxSystems 532Feature 19-2 A GeneralExpressionfor Calculating

Equilibrium Constantsfrom StandardPotentials 537

Contents vii

19D Constructing Redox Titration Curves 538

Feature 19-3 The Inverse Master Equation Approachfor Redox Titration Curves 547

Feature 19-4 Reaction Rates and ElectrodePotentials 552

19E Oxidation/Reduction Indicators 552

19F Potentiometric End Points 555

Chapter 20 Applications of OxidationlReductionTitrations 560

20A Auxiliary Oxidizing and ReducingReagents 56020B Applying Standard ReducingAgents 56220C Applying Standard Oxidizing Agents 566Feature 20-1 Determination of Chromium Speciesin

Water Samples 568Feature 20-2 Antioxidants 573

Chapter 21 Potentiometry 58821A GeneralPrinciples 58921B ReferenceElectrodes 590

21C Liquid-JunctionPotentials 59221D Indicator Electrodes 593

Feature 21-1 An EasilyConstructed Liquid-MembraneIon-Selective Electrode 606

Feature 21-2 The Structure and Performanceof lon-Selective Field EffectTransistors 608

Feature 21-3 Point-of-CareTesting:Blood GasesandBlood Electrolyteswith PortableInstrumentation 612

21E Instruments for Measuring Cell Potential 614Feature 21-4 The Loading Error in Potential

Measurements 614

Feature 21-5 Operational AmplifierVoltageMeasurements 615

21 F Direct Potentiometry 61621G Potentiometric Titrations 623

21H Potentiometric Determination of EquilibriumConstants 627

Chapter 22 Bulk Electrolysis: Electrogravimetry andCoulometry 633

22A The Effectof Currenton Cell Potential 634

Feature 22-1 Overvoltageand the Lead/AcidBattery 641

22B The Selectivityof ElectrolyticMethods 64122C Electrogravimetric Methods 64322D Coulometric Methods 649Feature 22-2 CoulometricTitrationof Chloride in

Biological Fluids 658

Chapter 23 Voltammetry 66523A Excitation Signals 66623B Linear SweepVoltammetry 667

viii Contents

23C Pulse Polarographic and VoltammetricMethods 689

Feature 23-1 Voltammetric Instruments Based onOperational Amplifiers 668

23D CyclicVoltammetry 694Feature 23-2 Modified Electrodes 697

23E Stripping Methods 69923F Voltammetry with Microelectrodes 703

PART V Spectrochemical Methods 707

A Conversation with Gary M. Hieftje 708

Chapter 24 Introduction to SpectrochemicalMethods 710

24A Properties of Electromagnetic Radiation 71124B Interaction of Radiation and Matter 714

Feature 24-1 Spectroscopy and the Discovery ofElements 71 7

24C Radiation Absorption 718Feature 24-2 Deriving Beer's Law 720Feature 24-3 Why Is a Red Solution Red? 72524D Emission of Electromagnetic Radiation 734

Chapter 25 Instruments for Optical Spectrometry 74425A Instrument Components 744Feature 25-1 Laser Sources: The Light Fantastic 748Feature 25-2 Derivation of Equation 25-1 754Feature 25-3 Ruling Gratings 756Feature 25-4 Deriving Equation 25-2 759Feature 25-5 Signals, Noise, and the Signal-to-Noise

Ratio 761

Feature 25-6 Measuring Photocurrents withOperational Amplifiers 769

25B Ultraviolet-Visible Photometers andSpectrophotometers 771

25C Infrared SpectrophotometersFeature 25-7 How Does a Fourier Transform Infrared

Spectrometer Work? 776

Chapter 26 Molecular Absorption Spectrometry 78426A Ultraviolet and Visible Molecular Absorption

Spectroscopy 78426B Automated Photometric and Spectrophotometric

Methods 807

26C Infrared Absorption Spectroscopy 811Feature 26-1 Using The Fourier Transform To Produce

Infrared Spectra 818

Chapter 27 Molecular Fluorescence Spectroscopy 82527 A Theory of Molecular Fluorescence 82527B Effect of Concentration On Fluorescence

Intensity 829

27C Fluorescence Instruments 830

27D Applications of Fluorescence Methods 831Feature 27-1 Use of Fluorescence Probes in Neurobiology:

Probing the Enlightened Mind 83227E Molecular Phosphorescence Spectroscopy 83427F Chemiluminescence Methods 835

Chapter 28 Atomic Spectroscopy 83928A Origins of Atomic Spectra 84028B Production of Atoms and Ions 843

28C Atomic Emission Spectrometry 85428D Atomic Absorption Spectrometry 858Feature 28-1 Determining Mercury by Cold-Vapor

Atomic Absorption Spectroscopy 86528E Atomic Fluorescence Spectrometry 86828F Atomic Mass Spectrometry 868

PART VI Kinetics and Separations 875

A Conversation with Isiah M. Warner 876

Chapter 29 Kinetic Methods of Analysis 87829A Rates of Chemical Reactions 879

Feature 29-1 Enzymes 88629B Determining Reaction Rates 892Feature 29-2 Fast Reactions and Stopped-Flow

Mixing 89229C Applications of Kinetic Methods 900Feature 29-3 The Enzymatic Determination of Urea 901

Chapter 30 Introduction to AnalyticalSeparations 906

30A Separation by Precipitation 90730B Separation of Species by Distillation 91130C Separation by Extraction 911Feature 30-1 Derivation of Equation 30-3 91330D Separating Ions by Ion Exchange 916Feature 30-2 Home Water Softeners 919

30E Chromatographic Separations 920Feature 30-3 What is the Source of the Terms Plate and

Plate Height? 930

Chapter 31 Gas Chromatography 94731A Instruments for Gas-Liquid Chromatography 94831 B Gas Chromatography Columns and Stationary

Phases 958

31 C Applications of Gas-Liquid Chromatography 963Feature 31-1 Use of GC/MS to identify a Drug

Metabolite in Blood 965

Feature 31-2 High-Speed Gas Chromatography 96931 D Gas-Solid Chromatography 970

Chapter 32 High-Perfonnance LiquidChromatography 973

31A Instrumentation 974

Feature 32-1 Liquid Chromatography (LC)/MassSpectrometry (MS) and LC/MS/NS 98032B High-Performance Partition Chromatography32C High-Performance Adsorption

Chromatography 98632D Ion-Exchange Chromatography 98632E Size-Exclusion Chromatography 988Feature 32-2 Buckyballs: The Chromatographic

Separation of Fullerenes 98932F Affinity Chromatography 99132G Chiral Chromatography 99132H Comparison of High-Performance Liquid

Chromatography and Gas Chromatography

982

992

Chapter 33 Miscellaneous Separation Methods 99633A Supercritical-Fluid Chromatography 99633B Planar Chromatography 100033C Capillary Electrophoresis 1003Feature 33-1 Capillary Array Electrophoresis in DNA

Sequencing 101033D Capillary Electrochromatography 101133E Field-Flow Fractionation 1013

PART VII Practical Aspects of ChemicalAnalysis 1021

A Conversation with Julie Leary 1022

Chapter 34 Analysis of Real Samples 102434A Real Samples 102434B Choice of Analytical Method 102634C Accuracy in the Analysis of Complex

Materials 1031

Chapter 35 Preparing Samples for Analysis

35A Preparing Laboratory Samples 103435B Moisture in Samples 103635C Determining Water in Samples 1039

1034

Chapter 36 Decomposing and Dissolving theSample 1041

36A Sources of Error in Decomposition andDissolution 1042

36B Decomposing Samples With Inorganic Acids inOpen Vessels 1042

36C Microwave Decompositions 104436D Combustion Methods for Decomposing Organic

Samples 104736E Decomposition of Inorganic Materials by

Fluxes 1049

Contents ix

Chapter 37 Selected Methods of Analysis

This chapter is only available as an Adobe Acrobat@PDF file on the Analytical Chemistry CD-ROMenclosed in this book or on our Web site athttp://chemistry.brookscole.com/skoogfac/.

37 A An Introductory Experiment37B Gravimetric Methods of Analysis37C Neutralization Titrations

37 D Precipitation Titrations37E Complex-Formation Titrations with EDTA37F Titrations with Potassium Permanganate37G Titrations with Iodine37H Titrations with Sodium Thiosulfate371 Titrations with Potassium Bromate37 J Potentiometric Methods

37K Electrogravimetric Methods37L Coulometric Titrations

37M Voltammetry37 N Methods Based on the Absorption of Radiation370 Molecular Fluorescence

37P Atomic Spectroscopy370 Application of Ion Exchange Resins37 R Gas-Liquid Chromatography

Glossary G-7

APPENDIX 1 The Literature of AnalyticalChemistry A-I

APPENDIX 2 Solubility Product Constants at25°C A-6

APPENDIX 3 Acid Dissociation Constants at25°C A-8

APPENDIX 4 Formation Constants at 25°C A-lO

APPENDIX 5 Standard and Formal ElectrodePotentials A-12

APPENDIX 6 Use of Exponential Numbers andLogarithms A-IS

APPENDIX 7 VolumetricCalculations Using Normalityand Equivalent Weight A-19

APPENDIX 8 Compounds Recommended for thePreparation of Standard Solutions ofSome Common Elements A-27

x Contents

APPENDIX 9 Derivation of Error PropagationEquations A-29

Answers to Selected Questions and Problems A-34

Index 1-1