Environmental Sciences 528L
Analysis of Environmental Contaminants
Southern
Spring Semester 2004
Lab Thursday (SL 0218 or 1209)
(
Course Instructor
Dr. Kevin A. Johnson, SL 3316 650-5934, kevjohn@siue.edu
Teaching Assistant
Sunitha Yerragodula 650-5063, sunu_y@rediffmail.com
Office Hours:
By appointment
Textbook:
Hand-outs of lab experiments will be provided. Students will need to read pertinent sections of the textbook (Analytical Chemistry for Technicians by Kenkel) for theoretical discussions and information.
Course Description:
Applications in environmental analysis, including: extraction, cleanup, and quantitative analysis of authentic samples. Experiments are designed to reinforce and apply theories taught in ENVS 528 (lecture). Hands on experience with the procedures, experimental methods, and instrumentation used for identification and quantitation of toxic substances and their transformation products in environmental and biological samples.
Objectives:
This course will emphasize laboratory methods in the preparation, extraction and analysis of toxicants in environmental samples. Sampling procedures, study design, and statistical treatment of experimental data will be a significant portion of the material that is discussed.
Laboratory experiments are designed to provide students with experience in sampling, isolation of analytes from sample matrices, determination of proper chromatographic or instrumental conditions, troubleshooting, and assessment of quantitative data. This background will enable students to pursue their own research problems in environmental toxicant analysis.
Analysis of Environmental Contaminants
Tentative Laboratory Schedule
Points
1. Laboratory check in/fun and games with balances and pipettes
A. Check in/measurement tests; Solution preparation each-10
2. Determination of lead in soils and water using graphite furnace atomic absorption spectroscopy
A. Digestion
B. AA analysis 50
3. Extraction of water for organophosphate (OPs) pesticides to evaluate their stability in water at varying pH=s using gas chromatography
A. Water extraction
B. Analysis 100
4. Evaluation of extraction methods for PAHs in soils and plant tissues using HPLC
A. Extraction
B. HPLC 100
5. Determination of unknowns using GC-MS: GC-MS operation and theory
A. Operation, Hands-on, GC-MS and other instrumental methods
B. GC-MS
C. RRTs on other GCs Each-100
6. Student-designed projects 160
Oral reports on projects 40
January A B March A B
15 Lab 1 Lab 1 04 Indep. projects
22 Lab 2 Lab 3 11 Spring Break
29 Lab 2 Lab 3 18 Indep. projects
25 Indep. projects
February April
05 Lab 3 Lab 2 01 Indep. projects
12 Lab 3 Lab 2 08 Indep. projects
19 Lab 4 Lab 4 15 Indep. projects
26 Lab 4 Lab 5 22 Lab 5 Lab 4
29 Lab 5 Lab 5
May
06 Group presentations,
Reports due
Grading
The course grade will be weighted as follows:
Laboratory performance: 10 %
Laboratory reports: 65 %
Project design and Presentation: 25 %
Performance will be rated by assessment of in-lab activities, such as compliance with safety requirements, development of lab skills in procedures and equipment operation, participation in experimental work, cleanliness, record keeping, and Attitude. Please note: disregarding safety rules, or abuse of instruments by non-compliance with mandated precautions for their operation will result in the loss of all performance credit and possible expulsion from the course. Additionally, failure to write up the pre-laboratory section or tardiness will result in an automatic loss of 10 points or approximately 4% of your grade for that experiment (see documentation section).
Project design will be rated according to originality, practicality, and efficiency in laboratory performance of the experiment. The experimental design and laboratory results of projects will be presented both as a written report and orally in class at the end of the semester. The written report will be due and presentations given during the last scheduled laboratory period (April 26th). Project presentation will be graded on presentation technique, organization and content. The report will be graded in a manner similar to that for the regular reports.
Reports
There will be 5 experiments and one student-designed project. All students will prepare a report for Experiments 1, 2, and 5, and each group will prepare a report for their Project. You can decide who will write up Experiments 3 and 4 (note: everyone will write up a long report and each group will turn in a report for each experiment). Division of responsibility for writing reports will be at the discretion each research group. It is strongly recommended that all members participate in data analysis. However, the grade will be assigned to the individual responsible for the report. Example reports will be handed out. Reports will be due 2 weeks from completion of the experiment, unless otherwise specified. Late reports will be assessed a 10 % penalty per week. Reports will not be accepted any latter than three weeks after the original due date. No reports will be accepted after April 26th. Reports for the student-designed project will be the equal responsibility of all members of the team (no late reports accepted).
Reports will be written with a brief introduction, methods (site laboratory handout unless there were deviations from the protocol), results, and discussion sections in a format similar to those found in the scientific literature. Be sure to answer all questions posed in the laboratory handout. Include examples of calculations used in generating reported results, and copies of representative standard and sample chromatograms (you will be docked points if you merely attach all chromatograms). The student-designed project report is the only one requiring a complete methods section.
Labeling:
All chromatograms included in reports need at least the following basic Information: column type (stationary phase, thickness, length, internal diameter, and flow rates), instrument settings (attenuation, temperature of all controlled zones), instrument identification, detector (type, wavelength if appropriate), date of analysis, sample or standard identification, volume injected, injection technique (manual or autosampler), and identification of peaks. ONLY turn in representative chromatograms--not all of them. Much of this can be obtained from a printout of the method from the instrument. Other information should be listed with the printout or identified on the chromatogram itself. Always indicate the identity of peaks on at least one of the chromatograms.
As a reminder of the correct format for graphs, see Figure 1. Note that the line does not extend beyond the data points. If it is necessary to extrapolate a line beyond the measured data points, this should be indicated by using a dashed line in that portion of the graph, and indicate that it is an extrapolation. Note, also that the line does not pass through the origin. The origin is not used as one of the points except when a measured variable actually is zero for a zero value sample. The line is not forced through the origin except in very specialized cases. Remember that the independent variable is something you already know (concentration, weight, time, etc.), and that the dependent variable is what you determine experimentally (peak area, enzyme activity, absorbance). If you ever have to generate a graph on log paper, do not take the log of the number and plot that, plot the actual number.
Laboratory basics
Documentation
You will be provided a laboratory notebook for the class. Prior to a lab experiment, students will be required to write-up a pre-laboratory summary and all calculations. The pre-laboratory summary should contain an overview of experimental procedures for that experiment. Notes, observations, deviations from the experimental procedure, as well as lab data should all be entered in this notebook. The SOP laboratory sample and reagent labeling and data sheet entries@ will be followed in this class. Reagent mixtures, sample extracts, and other solutions without identification will be discarded. Proper recording of data and labeling of materials is part of the performance grading of the class.
Safety
The chemicals we will be working with are toxic, as are many of the solvents and reagents used in analytical procedures. The MSDSs for all chemicals are available (in SL 1209 and on the Internet) and relevant ones should be consulted prior to an experiment. Toxicant concentrations encountered will generally be low, and represent little hazard. However, neat standards (i.e pure) and solutions of high concentrations must be handled carefully, and a cautious approach to any circumstance that may lead to chemical exposure is a wise habit to form. The observance of a few simple precautions will generally reduce or eliminate exposure. Conformance with these rules will be expected in all procedures used in this laboratory course.
Gloves will be worn when handling chemicals, solutions, and samples. Operations involving solvent evaporation or solution filtration will take place in fume hoods. No open-toed shoes, shorts, or other attire that does not cover the legs will be allowed. Lab coats are encouraged, however use of safety or prescription glasses are required in the laboratory at all times. Wearing of contact lenses are not generally a good idea, and should be avoided if possible. Additional safety precautions will be required for some procedures. You will be instructed in these during the relevant experiments. No food or drink will be brought into any of the laboratories. Only bring material essential to the experiments into the labs (e.g. leave backpacks, etc. elsewhere). Wash your hands before leaving the laboratory, and after handling any toxic materials.
Any spills must be immediately reported, first to any bystanders that may be affected, and then to one of the instructors or teaching assistants. Be sure to identify the closest location of safety equipment, such as, fire extinguishers, eye washes, and showers, in each laboratory you are working. Any injuries (cuts, burns, chemical exposures) occurring in the laboratory will be reported to the instructors.
For each experiment, make sure you understand the proper disposal procedure for any sample or solvent waste generated, and the proper location for placing used, contaminated glassware.
Health conditions which may limit or interrupt student participation in the class should be discussed confidentially with the course instructor at the beginning of the semester.
Policy Statement:
Academic Misconduct by Students
Faculty members retain their traditional authority to take disciplinary action in the event of academic misconduct. Acts of academic misconduct for which students are subject to sanctions include, without limitation, plagiarism, cheating, failure or refusal to follow clinical practice standards, falsifying or manufacturing scientific or scholarly experiments or research, and soliciting, aiding, abetting, concealing, or attempting such acts.
Plagiarism is defined as including, without limitation, the act of representing the work of another as one=s own. Plagiarism may consist of copying, paraphrasing, or otherwise using written or oral work of another without proper acknowledgment of the source or presenting oral or written material prepared by another as one=s own.
In the event of academic misconduct, the instructor may request the Student Assessments and Standards Committee of the Environmental Sciences Program to impose on a student the sanction of a failing grade on an individual assignment or on the course as a whole. The Director of the Program may recommend to the dean of Students other sanctions, such as dismissal from a major or from the University.
Students with
disabilities:
Persons with documented
disabilities should visit the Disability Support Services Office, located in
Peck Hall, room 1311, at their earliest convenience to meet the director and
discuss available services. The student
should also, make an appointment with the instructor as soon as possible to
discuss any special arrangements.
The following will be helpful for laboratory performance:
Unit conversions:
Many conversions of units will be necessary throughout the course. Recall the metric prefixes. Some of you may not be familiar with the low end: pico- (10-12) and fempto- (10-15). Concentrations of solutions used in instrumental analysis are frequently expressed in ng/μl (nanograms per micro liter), which is also, though somewhat inaccurately, expressed as ppm. Strictly speaking, ppm is weight to weight or volume to volume, and our solutions are actually weight to volume. Solutions expressed as a percent of one compound in another should indicate if the proportions are weight to weight (W/W), or weight to volume (W/V). For accuracy in reports, use the proper units for the reported data.
Calculations:
Make sure you are able to calculate, for example, a 0.2 mg/ml solution of a chemical in a solvent (what is a practical weight and volume to use?), and how much of this solution should be added in fortification of a 25 ml water sample to yield, after extraction and solvent reduction to a 2 ml final volume, a final concentration of 3 ng/μl. Also, what is the concentration in the water itself after it is fortified? If you find a 0.8 ng/μl concentration of a pesticide by gas chromatography, and it was from the analysis of a 5 ml final volume extract from a 3 g avian GI sample, what was the concentration in the GI tissue? If the whole bird weighed 500 g, what was the dose to the bird, assuming the entire dose was represented by the GI contents? Make sure you aren't going to have any trouble with these kinds of calculations and conversions before you need to use them in the laboratory or in reports.
Key for the Calculations:
Weights should be at least 10 mg for the balances we ordinarily use. This allows concentrations with 3 significant figures. For a 0.2 mg/ml solution, this would require a volume of 50 ml for a 10 mg weight. You generally want to generate the minimum volume of solution possible, as the excess must be disposed of as hazardous waste.
At 3 ng/μl, 2 ml of solution will contain 6 μg. You will need to add 30 μl of a 0.2 mg/ml solution to the water to obtain this final concentration. The water itself upon fortification will be at a concentration of 6 μg/25 ml, which would be 0.24 μg/ml.
At 0.8 ng/μl, the final 5 ml
solution contains 4 μg of the compound.
The concentration in 3 g tissue would be 4 μg/3 g, which would be
1.33 μg/g or 1.33 ppm. The dose for
the whole bird would be 4 μg/500 g, which would be 8 ng/g or 8 ppb.