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Teaching the Essential Principles Students need to understand the analytical thought processes and basic concepts before they can comprehend advanced technical principles. Miguel Valcárcel, University of Córdoba (Spain)
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ethods of teaching analytical chemistry should constantly evolve. The process of teaching and learning can improve by critically analyzing how information leads to training, the value of the material presented, what “messages” are delivered by the lecturer, and whether the course is consistent with real-world demands. Thus, continually renovating the curriculum is essential for training future analytical chemists (1). Innovations in the curriculum can be introduced in several ways. The approach proposed here, which mirrors ideas promoted by Pemberton and others (2), is a small “revolution” that emphasizes students learning basic analytical chemistry principles, so that training prevails over just memorizing information. This revolution also entails restructuring the curriculum. Adopting new and appealing ways of presenting the material, such as the problem-based learning approach, is helpful but not enough; we should also revise what we teach to ensure that students acquire a sound knowledge of the essential analytical chemistry principles (3–8).
Intrinsic and shared principles The pedagogical approach used in this article is based on what I label as the inherent fundamental principles of analytical chemistry and the principles the field shares with other scientific and technical areas. The “intrinsic” principles are those that distinguish analytical chemistry from other disciplines. They rely on the
assumption that analytical chemistry is a discipline of chemical and biochemical information (9). In my opinion, the
salient principles are seen in the definition of analytical chemistry as a discipline of chemical metrology, the interrelationship
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between analytical properties of results and methods (10), the use of reference materials for traceability, the essential steps that lead to qualitative and quantitative results, how analytical problems are tackled and solved (11), and the importance of “analytical quality” as practiced in quality control and assurance (12). The functions that make up each of these items are described in part I of the supporting information for this article, which
out first establishing the definition of analytical properties and their complementary and contradictory relationships. The student’s first contact with measurement standards often occurs when dealing with potassium phthalate and sodium carbonate, but without the necessary framework to understand standards and their relationship with traceability. The “bottom-up” approach that we propose starts with a description of the
Only a few books devote their opening chapters to fundamentals. is found at http://pubs.acs.org/ac. Analytical chemistry shares aspects with other areas such as chemistry, physics, biology, mathematics, and engineering. Typical examples include the use of analytical instrumentation, integrated chemical systems with a biological basis such as biosensors (13) and chemometrics. The principles are seen in the interface between analytical chemistry and other disciplines. According to Murray, these shared “boundaries” will persist and prosper (14). Although the intrinsic and shared characteristics are fundamental aspects of analytical chemistry, problems arise when the two sets are not properly distinguished—when one set prevails at the expense of the other, when advances in other areas are not used or adapted, and when fundamental characteristics are emphasized at the expense of applications.
Teaching the intrinsic principles In a “top-down” approach to teaching analytical chemistry, techniques and methods prevail, and the basic principles are delivered when needed. Crucial concepts of analytical chemistry such as standards, accuracy, calibration, sensitivity, and selectivity are presented when the first analytical technique is taught. Titrimetry and gravimetry are perfect examples. Students are told that titrimetry is less accurate but faster and simpler than gravimetry, and less selective and sensitive than most instrumental techniques. These topics are presented with-
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basic principles. This approach ensures that the analytical message from the teacher is consistent and the analytical perspective to measurements is never understated or lost. Finding a textbook to support this approach can be difficult. Most textbooks begin with ionic equilibria, basic laboratory operations, and applied statistics, which are followed by a detailed description of specific analytical methods and techniques (15). This approach teaches our discipline topic-by-topic (technique-by-technique or method-bymethod), which can provide a distorted picture of the analytical process. Some textbooks include an introductory chapter on principles, which does not adequately describe the intrinsic fundamentals. In fact, only a few books devote their opening chapters to fundamentals; one prominent example is the classic textbook by Laitinen and Harris, the second chapter of which deals with chemical standards (16). The same three approaches to the fundamentals are seen in analytical chemistry lectures. The tenets are either “diluted” with the bulk of the technical material, minimally covered, or given significant coverage from the very first lecture. The first approach misses the analytical perspective, and the second doesn’t provide a framework large enough to deliver this message. However, the third lecture style can give students the proper background while conveying the traditional topic-by-topic messages in a much
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more rational manner and even allow time for expanded discussions.
What is analytical chemistry? The goal is to teach students the basic tenets beginning in the first lecture and then reinforce and expand that knowledge when using the traditional learning materials. The time devoted to this introductory portion will vary depending on the length of the particular course and whether it is followed by other analytical chemistry courses. In our introductory courses, ~20% of lecture time is devoted to teaching these basics. This entails complementary strategies such as well-chosen examples (part II in supporting information), tests and questions that “immerse” students in the topics and assess how much they have learned (part III), and interactive seminars presented by students (part IV). Devoting a sizeable portion of the analytical chemistry curriculum to this approach entails carefully pruning the traditional teaching material and placing special emphasis on problem-based learning (5). This is a difficult task and is approached in different ways by different teachers. This introductory framework for teaching analytical chemistry can be divided into three blocks, which are presented in the order they should be taught because adherence to the proposed sequence is crucial for success. The first block introduces analytical chemistry, treats it as an information discipline, and emphasizes clear-cut differences from other disciplines. The topic of analytical properties—the attributes by which the quality of analytical tools and processes are judged—should be dealt with in a hierarchical manner and at reasonable depth (10). Traceability and standards, as well as their proper usage, are also essential topics. The second block should provide a global description of the way quantitative and qualitative measurements are made. Finally, the third block should be devoted to teaching analytical problems solving and explaining the relationship between analytical chemistry and quality issues. Depending on how much of the chemistry curriculum is devoted to the analytical sciences, the amount of introductory
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material can vary (part V in supporting information). A detailed description of the teaching material for each topic can be found elsewhere (17 ).
approach is an argument for increasing the analytical chemistry portion of the chemistry curriculum because its properties are different than those of other chemical disciplines.
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Assessing the proposal This approach has been used at the University of Córdoba (Spain) for the past 11 years to teach the first analytical chemistry course in the chemistry curriculum. The focus and content have been continuously refined into a consolidated introductory framework (17 ). Students are provided with a basic picture of the foundations and aims of analytical chemistry. We conclude that students have a realistic understanding of analytical chemistry based on the substantial increase in the number of students that pass their exams and the graduate students pursuing advanced degrees in analytical chemistry. The proposed
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Miguel Valcárcel is a professor at the University of Córdoba. His research interests include automation and simplification of analytical processes, sample screening systems, and analytical quality assurance. Address correspondence to Valcárcel at
[email protected].
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References (1 ) (2) (3) (4) (5) (6)
Smith, D. R. Anal. Chem. 2000, 70, 503 A. Pemberton, J. E. Anal. Chem. 2000, 70, 173 A. Wenzel, T. J. Anal. Chem. 1998, 70, 790 A–795 A. Murray, R. W. Anal. Chem. 1998, 70, 625 A. Wilson, G. S.; Anderson, M. R.; Lunte, C. E. Anal. Chem. 1997, 71, 677 A–681 A. Wenzel, T. J. Anal. Chem. 1999, 71, 693 A–695 A.
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Harris, D.C. Exploring Chemical Analysis; W. H. Freeman & Co.: New York, 1996. Tyson, J. Analysis. What Analytical Chemist Do; Royal Society of Chemistry: Cambridge, United Kingdom, 1988. Valcárcel, M. Trends Anal. Chem. 1997, 16, 124–131. Valcárcel, M.; Ríos, A. Anal. Chem. 1993, 65, 781 A–787 A.. Valcárcel, M.; Ríos, A. Trends Anal. Chem. 1997, 16, 385–393. Valcárcel, M.; Ríos, A. Trends Anal. Chem. 1994, 13, 17–23. Bard, A. J. Integral Chemical Systems; Wiley & Sons: New York, 1994. Murray, R. W. Anal. Chem. 1996, 68, 457 A. Locke, D. C.; Grossman, W. E. L. Anal. Chem. 1987, 59, 829 A–835 A. Laitinen, H. A.; Harris, W. E. Chemical Analysis; McGraw-Hill: New York, 1988. Valcárcel, M. Principles of Analytical Chemistry; Springer-Verlag: Heidelberg, Germany, 2000.
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