Breaking Stuff for Science

Most chemists will agree, a chemical spill on the floor is one of the most annoying things to have to deal with in a lab. With LBL policy, you have to adhere to the SWIMS protocol: Stop work, Warn others, Isolate the area, Monitor yourself, Stay in the area. Not to mention using the correct spill kit, dealing with all the paperwork of the spill and the opening of the spill kit, explaining to the safety people what happened and why (hopefully) it wasn’t your fault, etc.

Aside from making sure your people are competent and well trained, not much is often done to prevent spills. Engineering controls such as secondary containment, fume hoods, capped reagent bottles, etc. work well when people remember and plan to use them. All too often, we see good chemists forgo extra safety steps for speed or just plain old laziness. Sometimes, people get badly hurt not because they were bad chemists or bad scientists, but because they really needed to catch the 6:40 train that day.

What we need are more safety devices that prevent the accident caused by a failure of the preventative safety measures from being very dangerous. For example, take these safety-coated reagent bottles from VWR. They have some plastic coating (PVC I think) outside of the glass to prevent spills even if the glass shatters. Sure some solvents would eat through the coating, but it would still buy you time to contain the spill, or evacuate the room if necessary.

Recently, with LBL’s current safety kick, our lab ordered 40 of these babies to replace our older reagent bottles. Interestingly though, the coating is really hard to see. In fact, when we first examined the bottles there was a dispute between some lab members as to whether we received the correct shipment or not.

Here is how the bottle looked, next to a typical graduate student size scale:

Being scientists however, Mitch and I knew that we couldn’t just take VWR’s word that we now had safety-coated reagent bottles.  We needed to test whether it really had the safety-coating, whether the coating would actually stay intact after an impact strong enough to break the glass inside, and whether the coating would feel weird if we poked with our finger.







So, using my safety training, I put the reagent bottle into a plastic bag, and put the plastic bag inside a phototray. Note the secondary and tertiary containment.






I went and found a big wrench, donned my safety goggles, lab coat, nitrile gloves and put the soon to be destroyed bottle durability testing apparatus into a fume hood with the sash half open.  I then proceeded to smash it to pieces. It was a good day of science.

Here is the result after a good beating. The safety-coating is quite clearly visible now, along with the area where the hole would be, if the coating wasn’t still covering it. The interior glass shattered as expected, but the safety-coating simply flexed a bit and recovered. Also, no sharp pieces of glass pierced the coating, so the contents of the bottle would have been contained. It took a significant amount of effort with some sharp tweezers to illustrate the intact film of the coating. We also confirmed our hypothesis that poking the film with our finger would feel weird. The bottle met our expectations in all tested categories. It also looked really cool and took a great picture.

So in our effort to make the lab safer, we tested and confirmed the usefulness of these safety-coated reagent bottles in an easily repeatable scientific experiment. Tests would have been done in triplicate, however funding was abruptly cut off when we attempted to share our findings with others in the lab.  We recommend the safety-coated bottles for use throughout the chemistry lab. All waste was disposed of in coordinance with EH&S protocol.

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Shifting Constants

“]One of the first things that pops up in chemical education at the high school level is stoichiometric equations where a student is supposed to determine such things as yields, coefficients, and amounts of substance on a purely theoretical basis. This quickly becomes old hat for many students. In high school, my stoichiometric technique (if you could call it that) left a lot to be desired. I tended to “divine” my answers on tests and quizzes by playing with numbers until an answer made sense- then using it. It worked surprisingly well- and I got through classes learning very little but with decent grades. At the time, I wasn’t terribly interested in chemistry, and the class really was boring up until the end, where we got to learn about electrochemistry. I didn’t realize at the time that the subject matter wasn’t being done any justice. To me a mole was a mole was a mole. I just knew there were these numbers that I used to divine answers.

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Pushing the Envelope

When I was taking organic chemistry as a sophomore, the lecturing professor encouraged students to ask questions in his class.  His reason?  “If you have a question about something, chances are that someone else in the class has the same question.”  Likewise, I believe in open communication, particularly in learning the rudiments of organic chemistry.  Anyone who has taken a class with me will instantly recognize my trademark closing inquiry: “does anyone have any questions, comments or concerns.”  I give students one last chance to bring up any issues before the lab begins.  Usually, 95% of the time you can clearly hear a pin dropping on cotton during this time. 

The problem I’ve encountered over the past couple of years is the lack of preparedness by the average student.  Granted, the procedures will deviate from what’s in the book on occasion, but these concerns are addressed either in the prelab lecture or in my final instructions right as the lab period begins; I also leave notes about these issues on the whiteboard.  Remember the old cliché, “there’s no such thing as a stupid question”?  Some students recidivistically abuse this rule to the point of criminality.  Here are a few conversations between students (S) and teaching assistants (TA) over the past few years of teaching organic chemistry.  I’m sure you can supply your own examples.

S:            “I spilled my product in the hood.  What should I do?”

TA:         “A celebratory dance?”

S:             “My book says to add…um…sodium…brine…when the color changes.  Do I add it?” 

TA:          “Did the color change?” 

S:             Pause.  Smile.  “Yeah.” 

TA:          “Congratulations!  You answered your own question.  You’re one step closer to being a synthetic organic chemist.”

S:             “No.  This is my last semester of chemistry.”

TA:          “Really?”

S:             “What’s the molecular weight of anisole?”

TA:          “What’s the chemical formula?”

S:             “C…9…8…7…H…”

TA:          “What does your book say?”

S:             “I didn’t bring it.”

S:            “Can I go to the bathroom?”

TA:         “You’re in college.  You can do whatever you want.”

S:            “So, I don’t have to do the lab if I don’t want to?”

TA:         “I don’t care.”

S:            “So you’ll gimme an A?”

TA:         “No, I don’t care if you do the lab or not.  But you have to do the lab to get an A.”

S:            “That’s not fair.”

S:             “The book says use ‘dichloromethane,’ but there isn’t any in the hood.”

TA:          “You’re better off using ‘methylene chloride.’  It’s better for the environment.”

S:             “Is NMR-chloroform a halogen?”

TA:          “What do you think?”

S:             “I think it’s halogenated…no, wait, it’s non-halogenated.”

TA:          “Why?”

S:             “Didn’t you say ‘H’ is replaced by a ‘D’ or something?”

S:             “I have a question.”

TA:          “Okay.”  

S:             The student holds up a flask with a boiling stick in it, waiting for an answer.  “What should I do?” 

TA:          “Yes.”  He walks away.  The TA makes his way around the room and returns to the student 20 minutes later.

S:             “Should I add the hydrochloric acid or the sodium stuff?”

TA:          “Yes.”

S:             Sigh.  “That’s not helping.”

TA:          “True?”

S:             Sigh.

TA:          “Oh, wait, you wanted me to say ‘no.’”

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