talk dirty to me: teaching undergraduate students the ... · talk dirty to me: teaching...
TRANSCRIPT
Talk dirty to me: Teaching undergraduate students the importance of good hygiene in
the teaching laboratory
Luke Gallion, Dr. Michael Samide, Dr. Anne Wilson
Butler University, Department of Chemistry Indianapolis, IN
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Presentation Outline
• Significance of teaching undergraduates the importance of a clean lab
• Previous work/current practices • Butler University’s current laboratory
sequence • Modified laboratory sequence • Effects of the modified laboratory
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http://searchpp.com/messy-laboratory/
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Significance • Cleanliness and its
safety impacts lead to success in the laboratory
• “Maintain proper PPE” and “accident avoidance” ranked two highest safety priorities by industrial chemists
Fair, J. D.; Kleist, E. M.; Stoy, D. M. J. Chem. Educ. 2014, ASAP. DOI: 10.1021/ed400570f. http://www.amazon.com/Simpsons-Chemical-
Safety-Poster-Procedures/dp/B00BR0B9VG
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Previous Work – University of Kentucky
Safety in the Analytical Laboratory: Guidelines and Practices. www.chem.uky.edu/courses/che226/003-Safety_Guide.pdf (accessed November 25, 2014).
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• Safety guidelines are comprehensive but discuss what to do after an incident, not how to prevent
Previous Work – Iowa State University
• Great for cataloging safety issues
• Can be boring and dry
• Only reading it
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Miller, G. J.; Heideman, S. A.; Greenbowe, T. J. J. Chem. Educ. 2000, 77, 1185-1187.
Previous Work – Seattle University
• Held a safety training session – Alternate class discussion and worksheets – Students more engaged by breaking up
discussion and worksheets • Safety teams • Weekly pre-lab safety presentations
Alaimo, Peter J.; Langenhan, Joseph M.; Tanner, Martha J. J. Chem. Educ. 2010, 87, 856-861.
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Our Current Lab Sequence – Butler University
• Week 1: Check in, fermentation (aqueous sugar and yeast) set-up – 20 minutes
• Week 2: Filter solution, perform fractional distillation on filtrate – 3 hours
• Week 3: Identification of unknown compound using melting point, TLC, and mass spectrometry – 2 hours
Azman, A. M.; Barrett, J. A.; Darragh, M.; Esteb, J. J.; McNulty, L. M.; Morgan, P. M.; O’Reilly, S. A.; Wilson, A. M. J. Chem. Educ. 2013, 90, 140-141. 8
Modification • Week 1: Check in, fermentation (aqueous sugar and
yeast) set-up – Pour TLC plates – Evaluate cleanliness of laboratory – 2.5 hours
• Week 2: Filter solution, perform fractional distillation on filtrate – 3 hours
• Week 3: Identification of unknown compound using melting point, TLC, and mass spectrometry – Compare commercially-available TLC plate to hand-
poured TLC plate – 2.5 hours
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Procedure for Student-Poured Plates
• 1.2 g silica • 0.1 g CaSO4
• Fluorescence indicator green 254 nm
• 2.7 mL H2O
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Qualitative Results – Week 1
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Qualitative Results – Week 1
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Qualitative Results – Week 1
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Qualitative Results – Week 1
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Qualitative Results – Week 1
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Qualitative Results – Week 1
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Qualitative Results • “It was helpful to see how the plates are made/work.
However the homemade plates were a lot more difficult to use and I didn’t get any date for one of my compounds.”
• “Homemade TLC plates, in my opinion, don’t work as well as pre-made TLC plates”
• “Home-made plates are extremely fragile and therefore not reliable as some completely fell apart. Stick with the purchased commercial plates.”
• “The TLC plate I made fell apart when I placed it inside the beaker to run.”
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Qualitative Results
“Luke is cute”
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Quantitative Results
Mean scores 1= “Not Clean,” “No impact,” “Not worthwhile”;
6= “Very Clean,” Strong Impact,” “Very Worthwhile”
Survey Statements for Response
Students That Performed Modified
Laboratory
Control Group Students
p Values (Significance)
How would you have rated your lab cleanliness before
this laboratory? 4.45 ± 1.15 4.93 ± 1.03 0.0817,
significant
Indicate how this laboratory affected your view on lab
cleanliness. 4.42 ± 1.36 3.47 ± 1.55 0.0266,
significant
Now that you know how a TLC plate is prepared, how worthwhile is it to purchase
commercial plates?
5.19 ± 1.07 3.60 ± 1.68 0.0016, significant
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Quantitative Results
Correct Response, %
Survey Question Students That
Performed Modified Laboratory
Control Group p Values (significance)
Rf Calculation 93.5 80.0 0.0869, significant
Rf understanding 80.6 73.3 0.2925, not significant
Polarity/IM forces 71.0 33.3 0.0072, significant
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Summary/Conclusions
• Greater appreciation of lab cleanliness in hoods and common areas
• Greater realization of the importance of PPE
• Greater understanding of TLC • Greater appreciation of common
laboratory techniques
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Acknowledgements
• Butler University Department of Chemistry • Professor Kelsie Graham • Dr. Michael Samide • Dr. Anne Wilson • ACS National Meeting & Exposition • You!
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References 1. Banholzer, W. F.; Calabrese, G. S.; Confalone, P. Chem.
Eng. News 2013, 91 (18), 2. 2. Laboratory Safety. http://www.acs.org/content/dam/acsorg/
about/governance/committees/training/acsapproved/degreeprogram/laboratory-safety.pdf (accessed November 19, 2014).
3. Fair, J. D.; Kleist, E. M.; Stoy, D. M. J. Chem. Educ. 2014, ASAP. DOI: 10.1021/ed400570f.
4. Alaimo, Peter J.; Langenhan, Joseph M.; Tanner, Martha J. J. Chem. Educ. 2010, 87, 856-861.
5. Miller, G. J.; Heideman, S. A.; Greenbowe, T. J. J. Chem. Educ. 2000, 77, 1185-1187.
6. Hill Jr., R. H.; Nelson, D. A.. Chem. Health Safety, 2005, November-December, 19-23.
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References 7. Laboratory Health and Safety Training. https://www.amherst.edu/media/
view/64011/original/Laboratory%2BHealth%2Band%2BSafety%2BTraining.doc (accessed November 19, 2004).
8. The Chemical Safety Mechanism; Laboratory Housekeeping. http://www.ehs.wisc.edu/chem/LaboratoryHousekeeping.pdf (accessed November 19, 2014).
9. Safety Policies – College of Life Sciences. http://lifesciences.byu.edu/safety/LabSafety/SafetyPolicies.aspx (accessed August 22, 2014).
10. Safety in the Analytical Laboratory: Guidelines and Practices. www.chem.uky.edu/courses/che226/003-Safety_Guide.pdf (accessed November 25, 2014).
11. Miller, G. J.; Heideman, S. A.; Greenbowe, T. J. J. Chem. Educ. 2000, 77, 1185-1187.
12. Azman, A. M.; Barrett, J. A.; Darragh, M.; Esteb, J. J.; McNulty, L. M.; Morgan, P. M.; O’Reilly, S. A.; Wilson, A. M. J. Chem. Educ. 2013, 90, 140-141.
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Fluorescent Green Indicator
• Zinc silicate, Mn doped • Zn2SiO4
• http://www.sigmaaldrich.com/catalog/product/fluka/02554?lang=en®ion=US
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Previous Work
Hill Jr., R. H.; Nelson, D. A.. Chem. Health Safety, 2005, November-December, 19-23.
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Previous Work – Iowa State University
Miller, G. J.; Heideman, S. A.; Greenbowe, T. J. J. Chem. Educ. 2000, 77, 1185-1187.
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Quantitative Results – Appreciation of laboratory
cleanliness • How would you have rated your lab cleanliness
before this laboratory?1 = “Not clean” 6 = “Very Clean”
• Control Group (n=18): 4.93 ± 1.03 • Students that Performed Modified Laboratory
(n=33): 4.45 ± 1.15 • p Value: 0.0817 • Statistically significant at 90% confidence level
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Quantitative Results – Appreciation of laboratory
cleanliness • Indicate how this laboratory affected your view
on lab cleanliness. • 1 = “No impact” 6 = “Strong Impact” • Control Group (n=18): 3.47 ± 1.55 • Students that Performed Modified Laboratory
(n=33): 4.42 ± 1.36 • p Value: 0.0266 • Statistically significant at 90% confidence level
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Quantitative Results – Appreciation of common laboratory
techniques • Now that you know how to prepare a TLC plate,
how worthwhile is it to purchase commercial plates?
• 1 = “Not worthwhile” 6 = “Very Worthwhile” • Control Group (n=18): 3.60 ± 1.68 • Students that Performed Modified Laboratory
(n=33): 5.19 ± 1.07 • p Value: 0.0016 • Statistically significant at 90% confidence level
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Quantitative Results A student ran a TLC of an unknown compound on a commercial silica gel plate. The distance to the solvent front was 5.0 cm. The unknown compound being analyzed had an Rf of 0.4. How far did the compound travel up the plate? • Control Group (n=18): 80% correct • Students that Performed Modified Laboratory
(n=33): 93.5% correct • p Value: 0.0869 • Statistically significant at 90% confidence level
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Quantitative Results The student from the previous question (#4) wanted to replicate data. This time, the compound traveled 1.6 cm. What was the distance to the solvent front? • Control Group (n=18): 73.3% correct • Students that Performed Modified Laboratory
(n=33): 80.6% correct • p Value: 0.2925 • Not statistically significant at 90% confidence level
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Quantitative Results Compound A is very polar. Compound B is nonpolar. Compound C is of moderate polarity. If these three compounds were spotted on a TLC plate and a mobile phase of 90:10 hexanes: ethyl acetate was used, what would be the elution order of the compounds from lowest Rf value to highest Rf value be? • Control Group (n=18): 33.3% correct • Students that Performed Modified Laboratory (n=33):
71.0% correct • p Value: 0.0072 • Statistically significant at 90% confidence level
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