Exploring Chemical Analysis

Citation

Harris, D. C. (2012). Exploring Chemical Analysis (5th ed.). W. H. Freeman.

Chapter Summary

The fifth edition has about 640 pages in 24 chapters, numbered 0 to 23. Each chapter opens with a short real-world story (cocaine residues in river water, a titration on the Phoenix Mars Lander, the ozone hole), and the numbered sections are interleaved with boxes, classroom demonstrations and, in a few chapters, reference laboratory procedures. The publisher describes the book as a one-term introduction for students whose main interests generally lie outside chemistry. Back matter includes a glossary, four appendices of data (solubility products, acid dissociation constants, standard reduction potentials, and oxidation numbers with redox balancing), solutions to the "Ask Yourself" questions and answers to problems.

Chapter 0: The Analytical Process

A short orientation to the analytical chemist's job and the general steps of an analysis, with a box on constructing a representative sample.

Chapters 1–2: Chemical Measurements; Tools of the Trade

Chapter 1 covers SI units, unit conversion, concentration units, preparing solutions and a first look at the equilibrium constant. Chapter 2 is a guide to laboratory practice: safety, waste disposal and green chemistry, the lab notebook, the analytical balance, burets, volumetric flasks, pipets and syringes, filtration, drying, calibration of glassware and methods of sample preparation, with a reference procedure for calibrating a 50-mL buret.

Chapters 3–5: Math Toolkit; Statistics; Quality Assurance and Calibration Methods

The data-handling core. Chapter 3 treats significant figures, types of error, propagation of uncertainty, and an introduction to spreadsheets and graphing in Excel. Chapter 4 covers the Gaussian distribution, the F test, Student's t and a spreadsheet t test, the Grubbs test for outliers, least-squares fitting and calibration curves; a box explains the choice of null hypothesis with an epidemiology example. Chapter 5 introduces quality assurance (with control charts), method validation, standard addition and internal standards.

Chapters 6–7: Good Titrations; Gravimetric and Combustion Analysis

Chapter 6 sets out the principles and calculations of volumetric analysis, includes a section on chemistry in a fishtank (the publisher mentions classroom data from a saltwater aquarium), and then treats the solubility product, titration of a mixture and titrations involving silver ion. Chapter 7 covers precipitation, gravimetric calculations and combustion analysis.

Chapters 8–11: Introducing Acids and Bases; Buffers; Acid–Base Titrations; Polyprotic Acids and Bases

The longest sequence in the book. Chapter 8 relates [H⁺], [OH⁻] and pH and develops weak-acid and weak-base equilibria. Chapter 9 introduces the Henderson–Hasselbalch equation, buffer preparation and capacity, and how indicators work. Chapter 10 builds titration curves for strong and weak acids and bases, discusses finding the end point, describes Kjeldahl nitrogen analysis and shows how to model titrations in a spreadsheet. Chapter 11 extends this to diprotic systems, using amino acids as the example, and asks which species predominates at a given pH.

Chapters 12–13: A Deeper Look at Chemical Equilibrium; EDTA Titrations

Chapter 12 adds ionic strength, activity coefficients, charge and mass balances, the systematic treatment of equilibrium and fractional composition equations. Chapter 13 covers metal–chelate complexes, EDTA, metal-ion indicators, titration techniques, the pH dependence of metal–EDTA equilibria and titration curves.

Chapters 14–17: Electrode Potentials; Electrode Measurements; Redox Titrations; Instrumental Methods in Electrochemistry

Chapter 14 moves from redox chemistry and galvanic cells to standard potentials, the Nernst equation, the link between E° and the equilibrium constant, and reference electrodes. Chapter 15 covers indicator electrodes, junction potentials, ion-selective electrodes and pH measurement with the glass electrode. Chapter 16 treats the theory of redox titrations, redox indicators and titrations involving iodine. Chapter 17 introduces electrogravimetric and coulometric analysis, amperometry, voltammetry and polarography.

Chapters 18–20: Let There Be Light; Spectrophotometry: Instruments and Applications; Atomic Spectroscopy

Chapter 18 introduces the properties of light, absorption and Beer's law, with practical matters of measurement. Chapter 19 describes the spectrophotometer, analysis of mixtures, spectrophotometric titrations, what happens when a molecule absorbs light and luminescence in analysis. Chapter 20 covers atomization in flames, furnaces and plasmas, the effect of temperature, instrumentation, interference and inductively coupled plasma–mass spectrometry.

Chapters 21–23: Principles of Chromatography and Mass Spectrometry; Gas and Liquid Chromatography; Chromatographic Methods and Capillary Electrophoresis

Chapter 21 explains what chromatography is, how chromatograms are described and why bands spread, then introduces mass spectrometry and the information in a mass spectrum. Chapter 22 covers gas chromatography, classical and high-performance liquid chromatography, and sample preparation. Chapter 23 adds ion-exchange, ion, molecular-exclusion and affinity chromatography, then capillary electrophoresis, ending with DNA profiling on a chip.

Key Concepts

Chapters 0–5: Measurement and data

• Representative sample: a sample whose composition reflects that of the whole material being analysed.
• Propagation of uncertainty: how the uncertainties of measured quantities combine in a calculated result.
• F test, t test and Grubbs test: statistical tests for comparing precision, comparing means and deciding whether to reject an outlier.
• Standard addition and internal standards: calibration methods that compensate for matrix effects and for variations in instrument response.

Chapters 6–13: Equilibrium and titrations

• Solubility product: the equilibrium constant governing the dissolution of a sparingly soluble salt.
• Henderson–Hasselbalch equation: the relation between buffer pH, pKa and the ratio of base to acid.
• Systematic treatment of equilibrium: solving a system by writing all equilibria with charge and mass balances.
• EDTA titration: titration of metal ions with a chelating agent whose binding depends on pH.

Chapters 14–17: Electrochemistry

• Nernst equation: how cell potential depends on the concentrations (activities) of reactants and products.
• Ion-selective electrode: an electrode whose potential responds selectively to one ion, the glass pH electrode being the most familiar.

Chapters 18–23: Spectroscopy and separations

• Beer's law: absorbance is proportional to concentration and path length.
• Band spreading: the broadening of a chromatographic peak as it travels through the column, which limits resolution.
• Capillary electrophoresis: separation of ions by their migration in an electric field inside a narrow capillary.

Critical Analysis

Strengths

• Problem-solving support built in. According to the publisher, each worked example ends with a "Test Yourself" question that breaks the problem into simpler steps, and the contents show solutions to the "Ask Yourself" questions and answers to problems at the back. A separate solutions manual is also sold.
• Context throughout. Chapter openers and boxes connect methods to biology, environmental science, medicine and planetary science; the publisher lists new fifth-edition applications such as perchlorate detection on Mars, bisphenol A in food containers and DNA profiling on a chip.
• Spreadsheets without dependence on them. Spreadsheets are introduced early (Chapter 3) and reused for t tests, least squares and titration curves, but the publisher notes that the text can be used without ever opening one; spreadsheet problems are marked with an icon.
• Classroom demonstrations and lab practice. Demonstrations run through the equilibrium and electrochemistry chapters, and Chapter 2 with its reference procedures gives a practical introduction to the laboratory.

Limitations

• Weighted toward equilibrium and titration. Twelve of the 24 chapters (6–17) concern equilibria, titrations and electrochemistry, while spectroscopy and separations share six. Students who need depth in instrumental methods will need a further text.
• Dated software and examples. The fifth edition dates from 2012 and its spreadsheet instructions were updated to Excel 2007, so menus and commands will differ from current versions.
• No molecular-structure spectroscopy. Infrared and NMR spectroscopy do not appear in the contents; mass spectrometry is introduced within the chromatography chapter.

Where It Fits in the Course

This is the course's most approachable introduction to quantitative analysis. Harris and Lucy's Quantitative Chemical Analysis is by the same author and covers similar ground at greater length; the publisher's account of Exploring Chemical Analysis as a one-term course for students mainly outside chemistry makes it the choice for non-majors, while chemistry majors may go straight to Quantitative Chemical Analysis or use the two together. David Harvey's Analytical Chemistry 2.1 is an open text for a first analytical course that covers the same areas (equilibrium, statistics, spectroscopy, chromatography, electrochemistry) and is a useful free source of further explanations and problems.

For instrumental analysis, Rouessac and Rouessac's Chemical Analysis surveys more than 20 instrumental methods with little theory and fills the gap left by Harris's six instrumental chapters; Skoog, Holler and Crouch's Principles of Instrumental Analysis is the upper-level treatment of instrument principles and design. Bard, Faulkner and White's Electrochemical Methods is a graduate text that follows on from Chapters 14–17 for students who specialise in electrochemistry.

How to Use This Book

The book suits a one-term analytical chemistry course, especially for students in biology, geology, environmental science and other fields outside chemistry. General chemistry is the expected background, including stoichiometry and a first acquaintance with equilibrium, which Chapter 1 revisits.

A practical plan for one term:

• Core: Chapters 0–5 (measurement, laboratory tools, error, statistics and quality assurance), then Chapters 6 and 8–10 (titrations, acids and bases, buffers, acid–base titrations). These give the foundation for any analytical laboratory.
• Electrochemistry and spectroscopy: Chapters 14–15 and 18–19 for potentials, electrodes, Beer's law and spectrophotometry.
• Separations: Chapters 21–22 for the principles of chromatography and the main chromatographic methods.
• By time and interest: Chapter 7 (gravimetry and combustion), Chapters 11–13 (polyprotic systems, activity and the systematic treatment of equilibrium, EDTA), Chapters 16–17 (redox titrations and instrumental electrochemistry), Chapter 20 (atomic spectroscopy) and Chapter 23 (other chromatographic methods and capillary electrophoresis).

Work each worked example's "Test Yourself" question before moving on, then the "Ask Yourself" questions, and check both against the solutions at the back. Read Chapter 2 before the first laboratory session and keep the notebook practices it describes. Spreadsheet problems are worth attempting even with a newer version of Excel, since the techniques (least squares, titration curves) transfer directly.