In the Laboratory
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A New Project-Based Lab for Undergraduate Environmental and Analytical Chemistry Gianpiero Adami Department of Chemical Sciences, University of Trieste, Via L. Giorgieri 1, I-34127 Trieste, Italy;
[email protected] During the undergraduate analytical chemistry lab activity, students often execute a well-defined series of analytical operations that require only laboratory skills and data-analysis skills, but today’s students need a broader range of technical and nontechnical skills. The instructor’s ability to communicate knowledge and attract student interest is becoming more important in the various analytical chemistry curricula (1). It is also well demonstrated that good teaching requires an interpersonal relationship between students and instructor; moreover, it is very important that students are able to make independent choices and resolve problems (2). On the basis of these considerations and other learning experiences (2–7), a project-based lab has been developed (8) for third-year undergraduate chemistry students based on realworld applications. The course has a duration of 90 hours and is based on instrumental analytical chemistry, especially on chemical analyses of environmental samples, such as natural water samples. Each student follows the steps of the analytical procedure from sampling design, data treatment, and discussion: thus, the project name is TAP, total analytical procedure. To begin the project, students perform an initial sampling of natural freshwater. After sampling, various parameters are tested by means of chemical analyses with the goal of estimating the quality of the water. The data treatment is conducted during the next step of the project, focusing on the evaluation of data quality by means of replicates or by using reference materials. Finally, the students present their results in a public forum open to interested people, students, and researchers. The event is called Young Analytical Chemists day (YAC day). The final discussion leads to useful debate on the various theoretical and practical aspects of environmental and analytical chemistry.
Table 1. The Six Steps of TAP Project Step
Description
Duration
Location
I
Theoretical lessons
15 hours
Classroom
II
Project design
4 hours
Classroom
III
Sampling
4 hours
In situ
IV
Analysis (literature search)
6–8 weeks
Analytical chem lab
V
Data analysis (interpretation, final report)
2 weeks
PC lab
VI
Presentation
4 hours
Public room
Project Description The course consists of six steps (Table 1). During Step I, theoretical concepts (9–11) are discussed, especially on how to solve an analytical problems concerning environmental chemistry and water monitoring (river, lake, groundwater, etc.). In addition, the sampling steps and the applicable analytical techniques are discussed, such as conductimetry, UV– vis spectroscopy, atomic absorption spectroscopy, inductively coupled plasma atomic emission spectroscopy, and voltammetry. Parameters for data quality evaluation, how to present a result or a certified analysis in a correct way, and the major environmental laws pertaining to natural water control are also described during Step I. The project design is carried out in the classroom (Step II); each student chooses a water system (river, lake, pond, etc.) or a particular point (spring, source, etc.) relevant for a
Table 2. Chemical Species and Analytical Methods Employed during the TAP Project Species
Analytical Techniques
Instrument
Sources and Comments
Ions
Conductimetry (16)
Conductometer Metrohm model 660
Salt content; dilution effect
Nitrate
UV–Vis Spectroscopy (17, 18)
Lange LASA20
Fertilizers pollution
Ammonia Phosphate Total Phosphorus
UV–Vis Spectroscopy (17, 18)
Lange LASA20
Sewage urban pollution
Sulfates
UV–Vis Spectroscopy (17, 18)
Lange LASA20
Natural sources (gypsum) or industrial sources
Chloride
UV–Vis Spectroscopy (17, 18)
Lange LASA20
Seawater permeation or sewage pollution
Calcium, Magnesium
Atomic Absorption Spectroscopy (19)
Varian SpectrAA10
Hardness
Zinc, Iron
Plasma Atomic Emission Spectroscopy (20)
ICP-AES SpectroFlame Modula E (Spectro)
Sewage urban and industrial pollution
Copper
Voltammetry (21)
Polarecord 626 Metrohm
Industrial and agricultural pollution
Lead, Cadmium
Voltammetry (21)
Polarecord 626 Metrohm
Industrial pollution
www.JCE.DivCHED.org
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Vol. 83 No. 2 February 2006
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Journal of Chemical Education
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In the Laboratory
chemical–environmental study. Sampling points, sampling procedure, and treatment methods are also defined and chemical analyses decided. Sample containers are prepared in the laboratory, then each student, usually during the holiday periods, collects the required samples (Step III). Chemical analyses are performed in laboratory during Step IV (Table 2). Analytical methods are based on standard procedures mainly selected from the Standard Methods for the Examination of Water and Wastewater manual (12) and U.S. EPA methods (13). Details are available on the TAP project Web site (14,15) and in the Supplemental Material.W During this step each participant collects information and literature data about his specific water system, performing a literature search using the Internet, visiting the university libraries, and contacting local environmental control agencies. Step V requires data analysis by means of Excel (Microsoft Corp.) software, such that the results can be better analyzed and a final report written. An oral presentation is performed using PowerPoint software (22, 23). At the conclusion of the course, the presentations are discussed in a public forum during YAC day where students can describe their results and conclusions (Step VI). Public posters, brochures, and a Web site advertise this event (24). At the end of the presentations, each student receives a certificate of participation similar to those of a scientific congress. Some reports are published on the Internet where they can also be downloaded (15). Project Results and Student Responses Fifty-five students participated in the TAP project over the four-year period reported here. The studies, subdivided
Table 3. Students, Water Systems, and YAC Day Dates Academic Year
Number of Students
Number of Water Systems
1999– 2000
11
Water Typology
YAC Day
11
Spring: 6 Tap: 2 Ground: 3
Not held
May 30
2000– 2001
18
12
Spring: 2 Tap: 7 River: 2 Ground: 1
2001– 2002
11
9
Ground: 1 River: 3 Lake: 5
May 28
15
Spring: 2 Ground: 2 Lake: 2 River: 9
June 3
2002– 2003
15
by the different water systems, are listed in Table 3. The data obtained by students during 2000–2001 course are reported in Table 4. Data are divided in three subgroups: Friuli Plain, Trieste City, and Belluno Province water samples. Students are numbered from 1 to 18. During this academic year the reported data were the subject of 6 oral presentations at YAC day. Students debated the data and discussed the differences between the various water samples. In particular the high values of nitrates (students 5 and 18) and ammonium (students 1 and 7) suggested possible agricultural and sewage pollution.
Table 4. Student-Generated Data Obtained on Real Samples during 2000–2001 Academic Year Student Number
Conductivity/ (µS cm᎑1)
NO3/ (mg L᎑1)
NH4/ (mg L᎑1)
PO4/ (mg L᎑1)
Ca/ (mg L᎑1)
Mg/ (mg L᎑1)
Fe/ (mg L᎑1)
Zn/ (mg L᎑1)
Cu/ (mg L᎑1)
Pb/ (mg L᎑1)
Cd/ (mg L᎑1)
Friuli Plain (Friuli Venezia Giulia region) 1
453
05.3
0.10
