D. Harvey - Modern Analytical Chemistry (794078), страница 4
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A discussion of curve-fitting, includingthe statistical basis for linear regression (with and without weighting) also isincluded in this chapter.• More attention to selecting and obtaining a representative sample. The design of astatistically based sampling plan and its implementation are discussed earlier,and in more detail than in other textbooks. Topics that are covered includehow to obtain a representative sample, how much sample to collect, how manysamples to collect, how to minimize the overall variance for an analyticalmethod, tools for collecting samples, and sample preservation.• The importance of minimizing interferents is emphasized.
Commonly usedmethods for separating interferents from analytes, such as distillation, masking,and solvent extraction, are gathered together in a single chapter.• Balanced coverage of analytical techniques. The six areas of analyticaltechniques—gravimetry, titrimetry, spectroscopy, electrochemistry,chromatography, and kinetics—receive roughly equivalent coverage, meetingthe needs of instructors wishing to emphasize wet methods and thoseemphasizing instrumental methods. Related methods are gathered together in asingle chapter encouraging students to see the similarities between methods,rather than focusing on their differences.• An emphasis on practical applications. Throughout the text applications fromorganic chemistry, inorganic chemistry, environmental chemistry, clinicalchemistry, and biochemistry are used in worked examples, representativemethods, and end-of-chapter problems.• Representative methods link theory with practice.
An important feature of thistext is the presentation of representative methods. These boxed features presenttypical analytical procedures in a format that encourages students to thinkabout why the procedure is designed as it is.• Separate chapters on developing a standard method and quality assurance.
Twochapters provide coverage of methods used in developing a standard methodof analysis, and quality assurance. The chapter on developing a standardmethod includes topics such as optimizing experimental conditions usingresponse surfaces, verifying the method through the blind analysis ofstandard samples and ruggedness testing, and collaborative testing usingYouden’s two-sample approach and ANOVA.
The chapter on qualityassurance covers quality control and internal and external techniques forquality assessment, including the use of duplicate samples, blanks, spikerecoveries, and control charts.xiii1400-Fm 9/9/99 7:38 AM Page xivxivPreface• Problems adapted from the literature. Many of the in-chapter examples and endof-chapter problems are based on data from the analytical literature, providingstudents with practical examples of current research in analytical chemistry.• An emphasis on critical thinking. Critical thinking is encouraged throughproblems in which students are asked to explain why certain steps in ananalytical procedure are included, or to determine the effect of an experimentalerror on the results of an analysis.• Suggested experiments from the Journal of Chemical Education.
Rather thanincluding a short collection of experiments emphasizing the analysis ofstandard unknowns, an annotated list of representative experiments from theJournal of Chemical Education is included at the conclusion of most chapters.These experiments may serve as stand alone experiments, or as starting pointsfor individual or group projects.The Role of Equilibrium Chemistry in Analytical ChemistryEquilibrium chemistry often receives a significant emphasis in the introductory analytical chemistry course.
While an important topic, its overemphasis can cause students to confuse analytical chemistry with equilibrium chemistry. Although attention to solving equilibrium problems is important, it is equally important for students to recognize when such calculations are impractical, or when a simpler, morequalitative approach is all that is needed. For example, in discussing the gravimetricanalysis of Ag+ as AgCl, there is little point in calculating the equilibrium solubilityof AgCl since the concentration of Cl– at equilibrium is rarely known. It is important, however, to qualitatively understand that a large excess of Cl– increases the solubility of AgCl due to the formation of soluble silver-chloro complexes.
Balancingthe presentation of a rigorous approach to solving equilibrium problems, this textalso introduces the use of ladder diagrams as a means for providing a qualitative picture of a system at equilibrium. Students are encouraged to use the approach bestsuited to the problem at hand.Computer SoftwareMany of the topics covered in analytical chemistry benefit from the availability ofappropriate computer software. In preparing this text, however, I made a consciousdecision to avoid a presentation tied to a single computer platform or software package.
Students and faculty are increasingly experienced in the use of computers,spreadsheets, and data analysis software; their use is, I think, best left to the personal choice of each student and instructor.OrganizationThe textbook’s organization can be divided into four parts. Chapters 1–3 serve as anintroduction, providing an overview of analytical chemistry (Chapter 1); a review ofthe basic tools of analytical chemistry, including significant figures, units, and stoichiometry (Chapter 2); and an introduction to the terminology used by analyticalchemists (Chapter 3). Familiarity with the material in these chapters is assumedthroughout the remainder of the text.Chapters 4–7 cover a number of topics that are important in understanding howa particular analytical method works.
Later chapters are mostly independent of thematerial in these chapters. Instructors may pick and choose from among the topics1400-Fm 9/9/99 7:38 AM Page xvPrefaceof these chapters, as needed, to support individual course goals. The statistical analysis of data is covered in Chapter 4 at a level that is more complete than that found inother introductory analytical textbooks. Methods for calibrating equipment, standardizing methods, and linear regression are gathered together in Chapter 5. Chapter6 provides an introduction to equilibrium chemistry, stressing both the rigoroussolution to equilibrium problems, and the use of semi-quantitative approaches, suchas ladder diagrams. The importance of collecting the right sample, and methods forseparating analytes and interferents are covered in Chapter 7.Chapters 8–13 cover the major areas of analysis, including gravimetry(Chapter 8), titrimetry (Chapter 9), spectroscopy (Chapter 10), electrochemistry(Chapter 11), chromatography and electrophoresis (Chapter 12), and kinetic methods (Chapter 13).
Related techniques, such as acid–base titrimetry and redoxtitrimetry, or potentiometry and voltammetry, are gathered together in single chapters. Combining related techniques together encourages students to see the similarities between methods, rather than focusing on their differences. The first techniquepresented in each chapter is generally that which is most commonly covered in theintroductory course.Finally, the textbook concludes with two chapters discussing the design andmaintenance of analytical methods, two topics of importance to analytical chemists.Chapter 14 considers the development of an analytical method, including its optimization, verification, and validation. Quality control and quality assessment arediscussed in Chapter 15.AcknowledgmentsBefore beginning an academic career I was, of course, a student.
My interest inchemistry and teaching was nurtured by many fine teachers at Westtown FriendsSchool, Knox College, and the University of North Carolina at Chapel Hill; their collective influence continues to bear fruit. In particular, I wish to recognize DavidMacInnes, Alan Hiebert, Robert Kooser, and Richard Linton.I have been fortunate to work with many fine colleagues during my nearly 17years of teaching undergraduate chemistry at Stockton State College and DePauwUniversity. I am particularly grateful for the friendship and guidance provided byJon Griffiths and Ed Paul during my four years at Stockton State College. At DePauwUniversity, Jim George and Bryan Hanson have willingly shared their ideas aboutteaching, while patiently listening to mine.Approximately 300 students have joined me in thinking and learning about analytical chemistry; their questions and comments helped guide the development ofthis textbook.
I realize that working without a formal textbook has been frustratingand awkward; all the more reason why I appreciate their effort and hard work.The following individuals reviewed portions of this textbook at various stagesduring its development.David BallantineNorthern Illinois UniversityJohn E. BauerIllinois State UniversityAli BazziUniversity of Michigan–DearbornSteven D. BrownUniversity of DelawareWendy ClevengerUniversity of Tennessee–ChattanoogaCathy CobbAugusta State UniversityPaul FlowersUniversity of North Carolina–PembrokeNancy GordonUniversity of Southern Mainexv1400-Fm 9/9/99 7:38 AM Page xvixviPrefaceVirginia M.
IndiveroSwarthmore CollegeMichael JanusaNicholls State UniversityJ. David JenkinsGeorgia Southern UniversityRichard S. MitchellArkansas State UniversityGeorge A. Pearse, Jr.Le Moyne CollegeGary RaysonNew Mexico State UniversityDavid RedfieldNW Nazarene UniversityVincent RemchoWest Virginia UniversityJeanette K.
RiceGeorgia Southern UniversityMartin W. RoweTexas A&M UniversityAlexander ScheelineUniversity of IllinoisJames D. StuartUniversity of ConnecticutThomas J. WenzelBates CollegeDavid ZaxCornell UniversityI am particularly grateful for their detailed written comments and suggestions forimproving the manuscript. Much of what is good in the final manuscript is the resultof their interest and ideas. George Foy (York College of Pennsylvania), John McBride(Hofstra University), and David Karpovich (Saginaw Valley State University) checkedthe accuracy of problems in the textbook. Gary Kinsel (University of Texas atArlington) reviewed the page proofs and provided additional suggestions.This project began in the summer of 1992 with the support of a course development grant from DePauw University’s Faculty Development Fund. Additional financial support from DePauw University’s Presidential Discretionary Fund also isacknowledged.
Portions of the first draft were written during a sabbatical leave in theFall semester of the 1993/94 academic year. A Fisher Fellowship provided releasetime during the Fall 1995 semester to complete the manuscript’s second draft.Alltech and Associates (Deerfield, IL) graciously provided permission to use thechromatograms in Chapter 12; the assistance of Jim Anderson, Vice-President,and Julia Poncher, Publications Director, is greatly appreciated. Fred Soster andMarilyn Culler, both of DePauw University, provided assistance with some of thephotographs.The editorial staff at McGraw-Hill has helped guide a novice through theprocess of developing this text. I am particularly thankful for the encouragement andconfidence shown by Jim Smith, Publisher for Chemistry, and Kent Peterson,Sponsoring Editor for Chemistry. Shirley Oberbroeckling, Developmental Editor forChemistry, and Jayne Klein, Senior Project Manager, patiently answered my questions and successfully guided me through the publishing process.Finally, I would be remiss if I did not recognize the importance of my family’ssupport and encouragement, particularly that of my parents.
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