Talk dirty to me: Teaching undergraduate students the importance of good hygiene in the teaching laboratory

Transcription

1 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 1

2 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 2

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4 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: /ed400570f. Safety-Poster-Procedures/dp/B00BR0B9VG 4

5 Previous Work University of Kentucky Safety guidelines are comprehensive but discuss what to do after an incident, not how to prevent Safety in the Analytical Laboratory: Guidelines and Practices. (accessed November 25, 2014). 5

6 Previous Work Iowa State University Great for cataloging safety issues Can be boring and dry Only reading it Miller, G. J.; Heideman, S. A.; Greenbowe, T. J. J. Chem. Educ. 2000, 77,

7 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,

8 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,

9 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 handpoured TLC plate 2.5 hours 9

10 Procedure for Student-Poured Plates 1.2 g silica 0.1 g CaSO 4 Fluorescence indicator green 254 nm 2.7 ml H 2 O 10

11 Qualitative Results Week 1 11

12 Qualitative Results Week 1 12

13 Qualitative Results Week 1 13

14 Qualitative Results Week 1 14

15 Qualitative Results Week 1 15

16 Qualitative Results Week 1 16

17 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. 17

18 Qualitative Results Luke is cute 18

19 Quantitative Results Survey Statements for Response How would you have rated your lab cleanliness before this laboratory? Indicate how this laboratory affected your view on lab cleanliness. Mean scores 1= Not Clean, No impact, Not worthwhile ; 6= Very Clean, Strong Impact, Very Worthwhile Students That Performed Modified Laboratory Control Group Students 4.45 ± ± ± ± 1.55 p Values (Significance) , significant , significant Now that you know how a TLC plate is prepared, how worthwhile is it to purchase commercial plates? 5.19 ± ± , significant 19

20 Quantitative Results Correct Response, % Survey Question Students That Performed Modified Laboratory Control Group p Values (significance) R f Calculation , significant R f understanding , not significant Polarity/IM forces , significant 20

21 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 21

22 Acknowledgements Butler University Department of Chemistry Professor Kelsie Graham Dr. Michael Samide Dr. Anne Wilson ACS National Meeting & Exposition You! 22

23 References 1. Banholzer, W. F.; Calabrese, G. S.; Confalone, P. Chem. Eng. News 2013, 91 (18), Laboratory Safety. 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: /ed400570f. 4. Alaimo, Peter J.; Langenhan, Joseph M.; Tanner, Martha J. J. Chem. Educ. 2010, 87, Miller, G. J.; Heideman, S. A.; Greenbowe, T. J. J. Chem. Educ. 2000, 77, Hill Jr., R. H.; Nelson, D. A.. Chem. Health Safety, 2005, November-December,

24 References 7. Laboratory Health and Safety Training. view/64011/original/laboratory%2bhealth%2band%2bsafety %2BTraining.doc (accessed November 19, 2004). 8. The Chemical Safety Mechanism; Laboratory Housekeeping. (accessed November 19, 2014). 9. Safety Policies College of Life Sciences. safety/labsafety/safetypolicies.aspx (accessed August 22, 2014). 10. Safety in the Analytical Laboratory: Guidelines and Practices. (accessed November 25, 2014). 11. Miller, G. J.; Heideman, S. A.; Greenbowe, T. J. J. Chem. Educ. 2000, 77, 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,

25 Fluorescent Green Indicator Zinc silicate, Mn doped Zn 2 SiO 4 product/fluka/02554?lang=en&region=us 25

26 Previous Work Hill Jr., R. H.; Nelson, D. A.. Chem. Health Safety, 2005, November-December,

27 Previous Work Iowa State University Miller, G. J.; Heideman, S. A.; Greenbowe, T. J. J. Chem. Educ. 2000, 77,

28 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: Statistically significant at 90% confidence level 28

29 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: Statistically significant at 90% confidence level 29

30 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: Statistically significant at 90% confidence level 30

31 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 R f 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: Statistically significant at 90% confidence level 31

32 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: Not statistically significant at 90% confidence level 32

33 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 R f value to highest R f value be? Control Group (n=18): 33.3% correct Students that Performed Modified Laboratory (n=33): 71.0% correct p Value: Statistically significant at 90% confidence level 33