Contents 1. Introduction to Analytical Chemistry ............................................................................1 1.1 History of Development of Analytical Chemistry ..............................................1 1.2 What is Analytical Chemistry? .......................................................................... 3 1.3 The Process of Analytical Chemistry ................................................................. 3 1.4 Methods of Detecting Analytes ........................................................................ 4 1.5 Applications of Analytical Chemistry ................................................................5 1.6 Skills of an Analytical Chemist ........................................................................... 8 1.7 Analytical Chemistry and Society ..................................................................... 10 1.8 Terms to Know ................................................................................................... 11 1.9 Questions ........................................................................................................... 12 2. Statistical Treatment of Analytical Data ........................................................................ 13 2.1 Review of Fundamental Concepts ..................................................................... 13 2.2 Significant Figures ............................................................................................. 19 2.3 Limitations of Analytical Methods .................................................................... 20 2.4 Elementary Statistics Relevant to Analytical Chemistry .................................... 27 2.5 Validation ........................................................................................................... 36 2.6 Problems and Questions Analysis ..................................................................... 51 3. Quantitative Method of Analysis ................................................................................. 51 3.1 Introduction .......................................................................................................51 3.2 Classification of Quantitative Methods .............................................................51 3.3 General Laboratory Operations in Quantitative Method of Analysis ............... 55 3.4 Questions ........................................................................................................... 65 4 Gravimetric Analysis ...................................................................................................... 66 4.1 Precipitation Equilibria: The Solubility Product .................................................66 4.2 Unit Operations in Gravimetric Analysis ............................................................ 69
Contents
(x) 4.3 4.4
Role of Organic Precipitants in Gravimetric Analysis ........................................ 77 Problems and Questions .................................................................................... 79
5 Introduction to Volumetric Analysis .............................................................................. 81 5.1 Principles of Volumetric Analysis ....................................................................... 81 5.2 Classification of Volumetric Titrations ............................................................... 85 5.3 Problems and Questions .................................................................................... 85 6 Acid-Base Titrations ..................................................................................................... 86 6.1 Acid-Base Theories ........................................................................................... 86 6.2 Titrants in Non-Aqueous Titrants ..................................................................... 90 6.3 End-Point Detection ........................................................................................... 91 6.4 Different Types of Acid-Base Titrations ............................................................ 93 6.5 Polyprotic Acid .................................................................................................. 100 6.6 Applications of Acid/Base Titrations ................................................................ 102 6.7 Important Terms to Remember ........................................................................... 104 6.8 Important Points to Remember ........................................................................... 105 6.9 Questions and Problems .................................................................................... 107 7 Redox Titrations ............................................................................................................ 109 7.1 Redox Reaction Theory ...................................................................................... 109 7.2 Variation of Electrode Potential with Concentration: Nernst Equation .............. 123 7.3 Theory of Redox Titration Curves ..................................................................... 124 7.4 Oxidising Agents ................................................................................................ 128 7.5 Detection of End Point in Redox Titrations ....................................................... 133 7.6 Chemical Analysis by Redox Titration ............................................................... 136 7.7 Questions ........................................................................................................... 139 8 Complexometric Titrations ............................................................................................. 141 8.1 Theory ................................................................................................................ 142 8.2 Complexometric EDTA Titrations ....................................................................... 144 8.3 Complexometric Titration Curves ....................................................................... 145 8.4 Metallochromic Indicators ................................................................................. 148 8.5 Kinetics of Complexometric Titration ................................................................. 149 8.6 Typical EDTA Titrations .................................................................................... 150 8.7 Advantages of Complexometric Titrations ........................................................ 150 8.8 Important Points to be Remembered .................................................................. 159 8.9 Questions and Problems .................................................................................... 161
Contents
9 Chromatography ............................................................................................................ 162 9.1 Classification in Chromatography ..................................................................... 162 9.2 Theories of Chromatography ............................................................................. 166 9.3 Retardation Factor ............................................................................................. 167 9.4 Retention Volume ............................................................................................... 168 9.5 Column Capacity ................................................................................................ 168 9.6 Development of the Chromatogram ...................................................................169 9.7 Selection of a Chromatographic System ............................................................ 170 9.8 Important Points ................................................................................................ 171 9.9 Questions ........................................................................................................... 180 10 Paper Chromatography .................................................................................................. 181 10.1 Migration Parameters ......................................................................................... 181 10.2 Types of Paper Chromatography ....................................................................... 183 10.3 Experimental Details for Qualitative Analysis ....................................................185 10.4 Types of Paper ................................................................................................... 185 10.5 Stationary and Mobile Phases ........................................................................... 187 10.6 Multiple Development ....................................................................................... 189 10.7 Applications ...................................................................................................... 189 10.8 Important Points to Remember ........................................................................... 198 10.9 Questions and Problems .................................................................................... 199 11 Thin Layer Chromatography ......................................................................................... 200 11.1 Coating ............................................................................................................... 200 11.2 Experimental Techniques.................................................................................... 201 11.3 Superiority of TLC Over Other Chromatographic Techniques .......................... 206 11.4 Applications of TLC .......................................................................................... 207 11.5 Important Points ................................................................................................ 218 11.6 Advantages for TLC .......................................................................................... 218 11.7 Question .............................................................................................................222 12 Gas Chromatography (GC) ............................................................................................. 224 12.1 Introduction .......................................................................................................224 12.2 Principles of Gas Chromatographic Separations ................................................ 224 12.3 Gas-Liquid Chromatography .............................................................................. 224 12.4 Instrumentation .................................................................................................. 227 12.5 Applications ...................................................................................................... 235
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Contents
(xii) 12.6 12.7 12.8
Introduction and Development of Headspace Analysis .................................... 239 Important Points to Remember ........................................................................... 242 Questions ........................................................................................................... 250
13 High Performance Liquid Chromatography ................................................................... 252 13.1 Introduction ....................................................................................................... 252 13.2 Theory ................................................................................................................ 252 13.3 Instrumentation .................................................................................................. 253 13.4 Materials ............................................................................................................ 259 13.5 Reversed-Phase HPLC ....................................................................................... 262 13.6 Applications ...................................................................................................... 273 13.7 Important Points ................................................................................................ 283 13.8 Questions ........................................................................................................... 284 14 Column Chromatography .............................................................................................. 285 14.1 Columns ............................................................................................................. 285 14.2 Adsorption ......................................................................................................... 287 14.3 Partition Chromatography .................................................................................. 289 14.4 Detection of Column Effluent ............................................................................ 291 14.5 Applications ...................................................................................................... 291 14.6 Important Points ................................................................................................ 296 14.7 Questions ........................................................................................................... 298 15 Ion Exchange Chromatography ..................................................................................... 300 15.1 Introduction ....................................................................................................... 300 15.2 Exchange Materials ............................................................................................ 301 15.3 Cation Exchangers ............................................................................................. 304 15.4 Anion Exchangers .............................................................................................. 305 15.5 Regeneration ...................................................................................................... 306 15.6 Ion Exchange Capacity ....................................................................................... 306 15.7 Basis for Separations ......................................................................................... 306 15.8 Changing of Ionic Form ..................................................................................... 307 15.9 Mechanical and Chemical Stability .................................................................... 307 15.10 Kinetics .............................................................................................................. 308 15.11 Selectivity of Ion Exchangers ............................................................................ 308 15.12 The Column Process .......................................................................................... 310 15.13 Applications ...................................................................................................... 314
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Contents
15.14 15.15
Important Points ................................................................................................ 327 Questions ........................................................................................................... 329
16 Gel Permeation Chromatography (GPC) ........................................................................ 330 16.1 Introduction .......................................................................................................330 16.2 Packing Material ................................................................................................ 331 16.3 Column ............................................................................................................... 333 16.4 Gel Preparation ................................................................................................... 333 16.5 Packing of the Column ....................................................................................... 333 16.6 Application of the Sample ................................................................................. 334 16.7 Theory of Gel Permeation Chromatography ...................................................... 334 16.8 Column Calibration ............................................................................................. 345 16.9 Applications of Gel Permeation Chromatography ............................................. 345 16.10 Determination of the molecular weight distribution and average molecular weights of soluble oligomers and polymers ...................................... 346 16.11 Important Points ................................................................................................ 348 16.12 Questions ........................................................................................................... 350 17 Spectroscopy ................................................................................................................351 17.1 Introduction .......................................................................................................351 17.2 Wave Properties of Electromagnetic Radiation .................................................351 17.3 Relation Between Frequency, Velocity and Wave Number ................................ 353 17.4 Particle Properties of Electromagnetic Radiation ............................................... 353 17.5 Relation Between Wavelength and Particle Properties of Electromagnetic Radiation ............................................... 354 17.6 Electromagnetic Spectrum ..................................................................................354 17.7 Interaction of Electromagnetic Radiation With Matter ...................................... 356 17.8 Atomic Spectroscopy ........................................................................................357 17.9 Molecular Spectroscopy .................................................................................... 357 17.10 Questions ........................................................................................................... 361 18 UV Visible Spectroscopy ............................................................................................... 362 18.1 Electronic Transitions ........................................................................................362 18.2 Theory of Quantitative Aspects of UV Visible Spectroscopy ........................... 366 18.3 Instrumentation .................................................................................................. 369 18.4 Applications of Visible and UV Absorption Spectroscopy ...............................371 18.5 Important Points ................................................................................................ 383 18.6 Questions and Problems .................................................................................... 389
Contents
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19 Turbidimetry and Nephelometry ................................................................................... 392 19.1 Introduction ....................................................................................................... 392 19.2 Theory ................................................................................................................ 393 19.3 Effect of wavelength on scattering .................................................................... 394 19.4 Questions and Problems .................................................................................... 398 20 Molecular Fluorescence & Phosphorescence and Chemiluminescence Spectrometry 399 20.1 Introduction ....................................................................................................... 399 20.2 Theory ................................................................................................................ 400 20.3 Chemiluminescence ............................................................................................ 411 20.4 Questions and Problems .................................................................................... 414 21 Infra-Red Spectroscopy ................................................................................................ 415 21.1 Introduction ....................................................................................................... 415 21.2 Theory of IR Spectroscopy ............................................................................... 417 21.3 Instrumentation .................................................................................................. 419 21.4 Sample Preparation ............................................................................................. 423 21.5 Interpretation of Infrared spectra ....................................................................... 425 21.6 Applications of I.R. Spectroscopy ..................................................................... 429 21.7 Important Points ................................................................................................ 440 21.8 Questions and Problems .................................................................................... 441 22 Raman Spectroscopy ..................................................................................................... 444 22.1 22.2 22.3 22.4 22.5 22.6 22.7 22.8 22.9 22.10
Introduction ....................................................................................................... 444 Theory ................................................................................................................ 444 Stoke’s and Antistoke’s Lines ........................................................................... 445 Characteristics properties of Raman lines ......................................................... 446 Comparison Between Raman Spectra and Infrared Spectra ............................... 446 Instrumentation .................................................................................................. 448 Resonance Raman Scattering ............................................................................ 448 Applications of Raman Spectroscopy ............................................................... 448 Important Points ................................................................................................ 457 Questions and Problems .................................................................................... 462
23 Atomic Emission, Fluorescence and Absorption Spectroscopy .................................. 463 23.1 Basic Theory ...................................................................................................... 463 23.2 Principles–Electronic Transitions ...................................................................... 465 23.3 Theory of Atomic Spectra .................................................................................. 467
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Contents
23.4 23.5 23.6 23.7 23.8 23.9 23.10 23.11 23.12 23.13 23.14
Instrumentation .................................................................................................. 471 Theory of Operation .......................................................................................... 471 Instrumental Design of AAS .............................................................................. 472 Flame Atomisers .................................................................................................473 Alternative atomisation sources ........................................................................ 479 Advantages of Flame Atomisers include ........................................................... 485 Interferences in Atomic Absorption Methods ................................................... 490 Background Corrections .................................................................................... 494 Applications of AAS .......................................................................................... 496 Important Points ................................................................................................ 511 Questions ........................................................................................................... 514
24 Flame Photometry ..........................................................................................................516 24.1 Introduction .......................................................................................................516 24.2 Instrumentation: .................................................................................................518 24.3 The Flame and the Burner ..................................................................................519 24.4 The Photometer or Spectrometer ....................................................................... 523 24.5 Excitation of Spectra .......................................................................................... 526 24.6 Handling of Analytical Samples .........................................................................528 24.7 Internal Standards ..............................................................................................529 24.8 Precision and Accuracy .....................................................................................532 24.9 Questions and Problems .................................................................................... 534 25 Inductively Coupled Plasma-Optical Emission Spectrometry (ICP–OES) ..................... 537 25.1 Introduction .......................................................................................................537 25.2 Principle of the Inductively Coupled Plasma ..................................................... 539 25.3 Simultaneous Spectrometers .............................................................................. 542 25.4 Sequential spectrometers ................................................................................... 543 25.5 Analytical Output and Instrument Calibration .................................................. 543 25.6 Liberty of calibration lines ................................................................................. 544 25.7 Interferences ...................................................................................................... 545 25.8 Wave Length Selection ...................................................................................... 546 25.9 Sample Preparation Methodology ..................................................................... 547 25.10 Detection Limits in ICP Analysis ....................................................................... 549 25.11 Operating Conditions ......................................................................................... 550 25.12 Applications of ICP ............................................................................................ 552 25.13 Questions ........................................................................................................... 559
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Contents
26 Inductively Coupled Plasma–Mass Spectrometry (ICP-MS) ........................................ 560 26.1 History of ICP-MS ............................................................................................. 560 26.2 Theory of ICP-MS .............................................................................................. 560 26.3 Interferences ...................................................................................................... 614 26.4 Methodology ..................................................................................................... 624 26.5 Advantages of ICP-MS ...................................................................................... 626 26.6 Disadvantages of ICP-MS ................................................................................. 626 26.7 Applications ...................................................................................................... 626 26.8 Important Points ................................................................................................ 627 26.9 Questions ........................................................................................................... 632 27 Mass 27.1 27.2 27.3 27.4
Spectroscopy ...................................................................................................... 635 Introduction ....................................................................................................... 635 Instrumentation .................................................................................................. 638 Applications of Mass spectrometry .................................................................. 647 Questions and Problems .................................................................................... 650
28 Photoacoustic spectroscopy ........................................................................................ 651 28.1 Introduction ....................................................................................................... 651 28.2 Photoacoustic Effect .......................................................................................... 651 28.3 Photoacoustic Signal Generation, Processing and Interpretation ..................... 652 28.4 Photoacoustic Cell Design ................................................................................. 656 28.5 Sample Considerations ....................................................................................... 666 28.6 Applications ...................................................................................................... 668 28.7 Questions ........................................................................................................... 668 29 X-Ray Absorption, diffraction and Fluorescence Spectroscopy .................................. 669 29.1 Introduction ....................................................................................................... 669 29.2 Theory ................................................................................................................ 669 29.3 Interaction of X-ray with matter ......................................................................... 672 29.4 Instrumentation .................................................................................................. 674 29.5 Applications ...................................................................................................... 678 29.6 Questions and Problems .................................................................................... 681 30 Nuclear Magnetic Resonance Spectroscopy ................................................................ 682 30.1 Introduction ....................................................................................................... 682 30.2 Principle and Theory of NMR Process .............................................................. 683 30.3 The External Magnetic Field .............................................................................. 684
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Contents
30.4 30.5 30.6 30.7 30.8 30.9 30.10 30.11 30.12 30.13
Experimental Arrangements ...............................................................................685 Instrumentation .................................................................................................. 685 NMR Spectra and Molecular Structural Elucidation .......................................... 687 Shielding and Deshielding - Chemical Shift .......................................................688 Chemical Shift ....................................................................................................689 Dipolar Coupling ................................................................................................ 703 Quantitative Analysis ........................................................................................709 Applications ...................................................................................................... 712 Important Points ................................................................................................ 713 Problems .............................................................................................................715
31 Electron Spin Resonance Spectroscopy ....................................................................... 719 31.1 Introduction .......................................................................................................719 31.2 Paramagnetism ................................................................................................... 719 31.3 Questions and Problems .................................................................................... 741 32 Thermal Analysis ........................................................................................................... 743 32.1 General introduction .......................................................................................... 743 32.2 Thermogravimetry ..............................................................................................744 32.3 Effect of heating on the TG curves of siderite ................................................... 747 32.4 Questions ........................................................................................................... 763 32.5 Problems .............................................................................................................763 33 Electro Analytical Chemistry ......................................................................................... 765 33.1 Introduction .......................................................................................................765 33.2 Classification of Electrochemical Methods .......................................................765 33.3 Theory of Electrochemistry ...............................................................................767 33.4 Questions and Problems .................................................................................... 782 34 Potentiometry ................................................................................................................784 34.1 Introduction .......................................................................................................784 34.2 Reference Electrodes .......................................................................................... 784 34.3 The Standard Hydrogen Electrode (SHE) ..........................................................786 34.4 Questions and Problems .................................................................................... 814 35 Conductometry .............................................................................................................. 815 35.1 Introduction .......................................................................................................815 35.2 Conductivity ...................................................................................................... 815 35.3 Some Definitions and Relations .........................................................................816
Contents
(xviii) 35.4 35.5 35.6 35.7 35.8 35.9
Effect of dilution ................................................................................................ 816 Conductance Measurements ............................................................................. 818 Conductometric Titrations ................................................................................. 822 Applications of Conductance measurements .................................................... 825 Direct Concentration Determination .................................................................. 826 Questions and Problems .................................................................................... 827
36 Electrogravimetry .......................................................................................................... 828 36.1 Theory of electro-gravimetric analysis .............................................................. 828 36.2 Current in Electrochemical Cells ........................................................................ 830 36.3 Ohmic Potential: IR Drop .................................................................................... 830 36.4 Electrode Polarization And Electroanalytical Methods ..................................... 831 36.5 Completeness of deposition .............................................................................. 837 36.6 Electrolytic separation of metals ........................................................................ 838 36.7 Character of the deposit ..................................................................................... 839 36.8 Electrolytic separation of metals with controlled cathode potential .................. 839 36.9 Constant current electrolysis ............................................................................. 840 36.10 Some examples of metals which can be determined by electro-gravimetry ....... 842 36.11 Questions ........................................................................................................... 843 37 Coulometric methods of analysis .................................................................................. 844 37.1 Introduction ....................................................................................................... 844 37.2 Coulometry at constant potential ...................................................................... 844 37.3 Coulometric Titrations at Constant Current ...................................................... 847 37.4 Questions and Problems .................................................................................... 854 38 Voltammetry ................................................................................................................... 855 38.1 Introduction ....................................................................................................... 855 38.2 Instrumentation .................................................................................................. 856 38.3 Polarography ...................................................................................................... 862 38.4 Cyclic Voltammetry ............................................................................................. 873 38.5 Amperometry ..................................................................................................... 876 38.6 Questions and Problem ...................................................................................... 883
Index
........................................................................................................................... 887
