Analytical Chemistry – Gary D. Christian – 7th Edition

Chapter 1 Analytical Objectives, or: What Analytical Chemists Do 1

1.1 What Is Analytical Science?, 2

1.2 Qualitative and Quantitative Analysis: What Does Each Tell Us?, 3

1.3 Getting Started: The Analytical Process, 6

1.4 Validation of a Method—You Have to Prove It Works!, 15

1.5 Analyze Versus Determine—They Are Different, 16

1.6 Some Useful Websites, 16

Chapter 2 Basic Tools and Operations of Analytical Chemistry 20

2.1 The Laboratory Notebook—Your Critical Record, 20

2.2 Laboratory Materials and Reagents, 23

2.3 The Analytical Balance—The Indispensible Tool, 23

2.4 Volumetric Glassware—Also Indispensible, 30

2.5 Preparation of Standard Base Solutions, 42

2.6 Preparation of Standard Acid Solutions, 42

2.7 Other Apparatus—Handling and Treating Samples, 43

2.8 Igniting Precipitates—Gravimetric Analysis, 48

2.9 Obtaining the Sample—Is It Solid, Liquid, or Gas?, 49

2.10 Operations of Drying and Preparing a Solution of the Analyte, 51

2.11 Laboratory Safety, 57

Chapter 3 Statistics and Data Handling in Analytical Chemistry 62

3.1 Accuracy and Precision: There Is a Difference, 62

3.2 Determinate Errors—They Are Systematic, 63

3.3 Indeterminate Errors—They Are Random, 64

3.4 Significant Figures: How Many Numbers Do You Need?, 65

3.5 Rounding Off, 71

3.6 Ways of Expressing Accuracy, 71

3.7 Standard Deviation—The Most Important Statistic, 72

3.8 Propagation of Errors—Not Just Additive, 75

3.9 Significant Figures and Propagation of Error, 81

3.10 Control Charts, 83

3.11 The Confidence Limit—How Sure Are You?, 84

3.12 Tests of Significance—Is There a Difference?, 86

3.13 Rejection of a Result: The Q Test, 95

3.14 Statistics for Small Data Sets, 98

3.15 Linear Least Squares—How to Plot the Right Straight Line, 99

3.16 Correlation Coefficient and Coefficient of Determination, 104

3.17 Detection Limits—There Is No Such Thing as Zero, 105

3.18 Statistics of Sampling—How Many Samples, How Large?, 107

3.19 Powering a Study: Power Analysis, 110

3.20 Use of Spreadsheets in Analytical Chemistry, 112

3.21 Using Spreadsheets for Plotting Calibration Curves, 117

3.22 Slope, Intercept, and Coefficient of Determination, 118

3.23 LINEST for Additional Statistics, 119

3.24 Statistics Software Packages, 120

Chapter 4 Good Laboratory Practice: Quality Assurance and Method Validation 132

4.1 What Is Good Laboratory Practice?, 133

4.2 Validation of Analytical Methods, 134

4.3 Quality Assurance—Does the Method Still Work?, 143

4.4 Laboratory Accreditation, 144

4.5 Electronic Records and Electronic Signatures: 21 CFR, Part 11, 145

4.6 Some Official Organizations, 146

Chapter 5 Stoichiometric Calculations: The Workhorse of the Analyst 149

5.1 Review of the Fundamentals, 149

5.2 How Do We Express Concentrations of Solutions?, 152

5.3 Expressions of Analytical Results—So Many Ways, 159

5.4 Volumetric Analysis: How Do We Make Stoichiometric Calculations?, 166

5.5 Volumetric Calculations—Let's Use Molarity, 169

5.6 Titer—How to Make Rapid Routine Calculations, 179

5.7 Weight Relationships—You Need These for Gravimetric Calculations, 180

Chapter 6 General Concepts of Chemical Equilibrium 188

6.1 Chemical Reactions: The Rate Concept, 188

6.2 Types of Equilibria, 190

6.3 Gibbs Free Energy and the Equilibrium Constant, 191

6.4 Le Châtelier's Principle, 192

6.5 Temperature Effects on Equilibrium Constants, 192

6.6 Pressure Effects on Equilibria, 192

6.7 Concentration Effects on Equilibria, 193

6.8 Catalysts, 193

6.9 Completeness of Reactions, 193

6.10 Equilibrium Constants for Dissociating or Combining Species—Weak Electrolytes and Precipitates, 194

6.11 Calculations Using Equilibrium Constants—Composition at Equilibrium?, 195

6.12 The Common Ion Effect—Shifting the Equilibrium, 203

6.13 Systematic Approach to Equilibrium Calculations—How to Solve Any Equilibrium Problem, 204

6.14 Some Hints for Applying the Systematic Approach for Equilibrium Calculations, 208

6.15 Heterogeneous Equilibria—Solids Don't Count, 211

6.16 Activity and Activity Coefficients—Concentration Is Not the Whole Story, 211

6.17 The Diverse Ion Effect: The Thermodynamic Equilibrium Constant and Activity Coefficients, 217

Chapter 7 Acid–Base Equilibria 222

7.1 The Early History of Acid—Base Concepts, 222

7.2 Acid–Base Theories—Not All Are Created Equal, 223

7.3 Acid–Base Equilibria in Water, 225

7.4 The pH Scale, 227

7.5 pH at Elevated Temperatures: Blood pH, 231

7.6 Weak Acids and Bases—What Is the pH?, 232

7.7 Salts of Weak Acids and Bases—They Aren't Neutral, 234

7.8 Buffers—Keeping the pH Constant (or Nearly So), 238

7.9 Polyprotic Acids and Their Salts, 245

7.10 Ladder Diagrams, 247

7.11 Fractions of Dissociating Species at a Given pH: α Values—How Much of Each Species?, 248

7.12 Salts of Polyprotic Acids—Acid, Base, or Both?, 255

7.13 Physiological Buffers—They Keep You Alive, 261

7.14 Buffers for Biological and Clinical Measurements, 263

7.15 Diverse Ion Effect on Acids and Bases: cKa and cKb—Salts Change the pH, 266

7.16 log C—pH Diagrams, 266

7.17 Exact pH Calculators, 269

Chapter 8 Acid–Base Titrations 281

8.1 Strong Acid versus Strong Base—The Easy Titrations, 282

8.2 The Charge Balance Method—An Excel Exercise for the Titration of a Strong Acid and a Strong Base, 285

8.3 Detection of the End Point: Indicators, 288

8.4 Standard Acid and Base Solutions, 290

8.5 Weak Acid versus Strong Base—A Bit Less Straightforward, 290

8.6 Weak Base versus Strong Acid, 295

8.7 Titration of Sodium Carbonate—A Diprotic Base, 296

8.8 Using a Spreadsheet to Perform the Sodium Carbonate—HCl Titration, 298

8.9 Titration of Polyprotic Acids, 300

8.10 Mixtures of Acids or Bases, 302

8.11 Equivalence Points from Derivatives of a Titration Curve, 304

8.12 Titration of Amino Acids—They Are Acids and Bases, 309

8.13 Kjeldahl Analysis: Protein Determination, 310

8.14 Titrations Without Measuring Volumes, 312

Chapter 9 Complexometric Reactions and Titrations 322

9.1 Complexes and Formation Constants—How Stable Are Complexes?, 322

9.2 Chelates: EDTA—The Ultimate Titrating Agent for Metals, 325

9.3 Metal–EDTA Titration Curves, 331

9.4 Detection of the End Point: Indicators—They Are Also Chelating Agents, 334

9.5 Other Uses of Complexes, 336

9.6 Cumulative Formation Constants β and Concentrations of Specific Species in Stepwise Formed Complexes, 336

Chapter 10 Gravimetric Analysis and Precipitation Equilibria 342

10.1 How to Perform a Successful Gravimetric Analysis, 343

10.2 Gravimetric Calculations—How Much Analyte Is There?, 349

10.3 Examples of Gravimetric Analysis, 353

10.4 Organic Precipitates, 353

10.5 Precipitation Equilibria: The Solubility Product, 355

10.6 Diverse Ion Effect on Solubility: Ksp and Activity Coefficients, 361

Chapter 11 Precipitation Reactions and Titrations 366

11.1 Effect of Acidity on Solubility of Precipitates: Conditional Solubility Product, 366

11.2 Mass Balance Approach for Multiple Equilibria, 368

11.3 Effect of Complexation on Solubility: Conditional Solubility Product, 372

11.4 Precipitation Titrations, 374

Chapter 12 Electrochemical Cells and Electrode Potentials 383

12.1 What Are Redox Reactions?, 384

12.2 Electrochemical Cells—What Electroanalytical Chemists Use, 384

12.3 Nernst Equation—Effects of Concentrations on Potentials, 390

12.4 Formal Potential—Use It for Defined Nonstandard Solution Conditions, 394

12.5 Limitations of Electrode Potentials, 395

Chapter 13 Potentiometric Electrodes and Potentiometry 399

13.1 Metal Electrodes for Measuring the Metal Cation, 400

13.2 Metal–Metal Salt Electrodes for Measuring the Salt Anion, 401

13.3 Redox Electrodes—Inert Metals, 402

13.4 Voltaic Cells without Liquid Junction—For Maximum Accuracy, 404

13.5 Voltaic Cells with Liquid Junction—The Practical Kind, 405

13.6 Reference Electrodes: The Saturated Calomel Electrode, 407

13.7 Measurement of Potential, 409

13.8 Determination of Concentrations from Potential Measurements, 411

13.9 Residual Liquid-Junction Potential—It Should Be Minimized, 411

13.10 Accuracy of Direct Potentiometric Measurements—Voltage Error versus Activity Error, 412

13.11 Glass pH Electrode—Workhorse of Chemists, 413

13.12 Standard Buffers—Reference for pH Measurements, 418

13.13 Accuracy of pH Measurements, 420

13.14 Using the pH Meter—How Does It Work?, 421

13.15 pH Measurement of Blood—Temperature Is Important, 422

13.16 pH Measurements in Nonaqueous Solvents, 423

13.17 Ion-Selective Electrodes, 424

13.18 Chemical Analysis on Mars using Ion-Selective Electrodes, 432

Chapter 14 Redox and Potentiometric Titrations 437

14.1 First: Balance the Reduction–Oxidation Reaction, 437

14.2 Calculation of the Equilibrium Constant of a Reaction—Needed to Calculate Equivalence Point Potentials, 438

14.3 Calculating Redox Titration Curves, 441

14.4 Visual Detection of the End Point, 445

14.5 Titrations Involving Iodine: Iodimetry and Iodometry, 447

14.6 Titrations with Other Oxidizing Agents, 452

14.7 Titrations with Other Reducing Agents, 454

14.8 Preparing the Solution—Getting the Analyte in the Right Oxidation State before Titration, 454

14.9 Potentiometric Titrations (Indirect Potentiometry), 456

Chapter 15 Voltammetry and Electrochemical Sensors 466

15.1 Voltammetry, 467

15.2 Amperometric Electrodes—Measurement of Oxygen, 472

15.3 Electrochemical Sensors: Chemically Modified Electrodes, 472

15.4 Ultramicroelectrodes, 474

15.5 Microfabricated Electrochemical Sensors, 474

15.6 Micro and Ultramicroelectrode Arrays, 475

Chapter 16 Spectrochemical Methods 477

16.1 Interaction of Electromagnetic Radiation with Matter, 478

16.2 Electronic Spectra and Molecular Structure, 484

16.3 Infrared Absorption and Molecular Structure, 489

16.4 Near-Infrared Spectrometry for Nondestructive Testing, 491

16.5 Spectral Databases—Identifying Unknowns, 493

16.6 Solvents for Spectrometry, 493

16.7 Quantitative Calculations, 494

16.8 Spectrometric Instrumentation, 504

16.9 Types of Instruments, 519

16.10 Array Spectrometers—Getting the Entire Spectrum at Once, 522

16.11 Fourier Transform Infrared Spectrometers, 523

16.12 Near-IR Instruments, 525

16.13 Spectrometric Error in Measurements, 526

16.14 Deviation from Beer's Law, 527

16.15 Fluorometry, 530

16.16 Chemiluminescence, 538

16.17 Fiber-Optic Sensors, 540

Chapter 17 Atomic Spectrometric Methods 548

17.1 Principles: Distribution between Ground and Excited States—Most Atoms Are in the Ground State, 550

17.2 Flame Emission Spectrometry, 553

17.3 Atomic Absorption Spectrometry, 556

17.4 Sample Preparation—Sometimes Minimal, 567

17.5 Internal Standard and Standard Addition Calibration, 567

17.6 Atomic Emission Spectrometry: The Induction Coupled Plasma (ICP), 569

17.7 Atomic Fluorescence Spectrometry, 574

Chapter 18 Sample Preparation: Solvent and Solid-Phase Extraction 579

18.1 Distribution Coefficient, 579

18.2 Distribution Ratio, 580

18.3 Percent Extracted, 581

18.4 Solvent Extraction of Metals, 583

18.5 Accelerated and Microwave-Assisted Extraction, 585

18.6 Solid-Phase Extraction, 586

18.7 Microextraction, 590

18.8 Solid-Phase Nanoextraction (SPNE), 593

Chapter 19 Chromatography: Principles and Theory 596

19.1 Countercurrent Extraction: The Predecessor to Modern Liquid Chromatography, 598

19.2 Principles of Chromatographic Separations, 603

19.3 Classification of Chromatographic Techniques, 604

19.4 Theory of Column Efficiency in Chromatography, 607

19.5 Chromatography Simulation Software, 616

Chapter 20 Gas Chromatography 619

20.1 Performing GC Separations, 620

20.2 Gas Chromatography Columns, 623

20.3 Gas Chromatography Detectors, 630

20.4 Temperature Selection, 638

20.5 Quantitative Measurements, 639

20.6 Headspace Analysis, 641

20.7 Thermal Desorption, 641

20.8 Purging and Trapping, 642

20.9 Small and Fast, 643

20.10 Separation of Chiral Compounds, 644

20.11 Two-Dimensional GC, 645

Chapter 21 Liquid Chromatography and Electrophoresis 649

21.1 High-Performance Liquid Chromatography, 651

21.2 Stationary Phases in HPLC, 654

21.3 Equipment for HPLC, 665

21.4 Ion Chromatography, 692

21.5 HPLC Method Development, 700

21.6 UHPLC and Fast LC, 701

21.7 Open Tubular Liquid Chromatography (OTLC), 702

21.8 Thin-Layer Chromatography, 702

21.9 Electrophoresis, 708

21.10 Capillary Electrophoresis, 711

21.11 Electrophoresis Related Techniques, 724

Chapter 22 Mass Spectrometry 735

22.1 Principles of Mass Spectrometry, 735

22.2 Inlets and Ionization Sources, 740

22.3 Gas Chromatography–Mass Spectrometry, 741

22.4 Liquid Chromatography–Mass Spectrometry, 746

22.5 Laser Desorption/Ionization, 750

22.6 Secondary Ion Mass Spectrometry, 752

22.7 Inductively Coupled Plasma–Mass Spectrometry, 753

22.8 Mass Analyzers and Detectors, 753

22.9 Hybrid Instruments and Tandem Mass Spectrometry, 764

Chapter 23 Kinetic Methods of Analysis 769

23.1 Kinetics—The Basics, 769

23.2 Catalysis, 771

23.3 Enzyme Catalysis, 772

Chapter 24 Automation in Measurements 784

24.1 Principles of Automation, 784

24.2 Automated Instruments: Process Control, 785

24.3 Automatic Instruments, 787

24.4 Flow Injection Analysis, 789

24.5 Sequential Injection Analysis, 791

24.6 Laboratory Information Management Systems, 792

Clinical Chemistry C1

25.1 Composition of Blood, C1

25.2 Collection and Preservation of Samples, C3

25.3 Clinical Analysis—Common Determinations, C4

25.4 Immunoassay, C6

Chapter 26 Environmental Sampling and Analysis EN1

26.1 Getting a Meaningful Sample, EN1

26.2 Air Sample Collection and Analysis, EN2

26.3 Water Sample Collection and Analysis, EN9

26.4 Soil and Sediment Sampling, EN11

26.5 Sample Preparation for Trace Organics, EN12

26.6 Contaminated Land Sites—What Needs to Be Analyzed?, EN12

26.7 EPA Methods and Performance-Based Analyses, EN13