Poll (Updated and Bumped)

In response to the post on the M&M caper, a representative from a company named ASPEX, a provider of “microanalysis solutions for a wide range of production environments” including SEM and EDX analysis, contacted us and offered a free SEM scan of any object of our choosing using their benchtop SEM (updated to massage wording).  Naturally, we jumped at the opportunity.

I immediately contacted the Raleigh News and Observer to see if the subject of the M&M article wanted to provide some of the tooth-like sugar lump for SEM analysis.  How cool would that have been?  I received two responses from the N&O.  a) the state used all of the sample in figuring out the composition of the sugar lump (really?  The WHOLE thing to find out it was sugar?), and b) my use of the N&O’s image was in violation of copyright, and I needed to remove the image.  oops.

So, since we can’t get our hands on that, let’s have a vote to see what we should send to ASPEX for analysis!  Choose from a few foodstuffs as well as a few labstuffs, or tell us what you want to see up close and personal.  Voting will be open until Thursday so cast your vote NOW!

ASPEX also wants readers to know that you, too, can send in any sample of your choosing for a complimentary SEM scan!  Just head over to their website and fill out the form.  If the object you vote for doesn’t win, send it yourself!  Make sure you let us know, so we can link to the results and have a regular picture swap.

Happy scanning.

RESULTS!

Well, thanks to everyone who voted. The teflon stir bar won a decisive plurality, getting 40.4% of the vote. An M&M made a strong late game run, and finished 2nd with 23.4%. Rounding out the top 5 were Peanut (17%), Rubber septum (10.6%) and Other (8.5%).

I’ll be sending ASPEX a nice, scuffed up, old teflon stir bar soon. Let’s see what happens to one of these things after years of hard work.

Don’t forget, if you want to send in something of your own for a free SEM scan, just head to their website for the form to fill out.

Here is a picture of  a ‘new’ stir bar and the stir bar we’re sending for SEM to see what it looks like really really close up.

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A Tooth in an M&M?

A Raleigh, NC, woman bit into a peanut M&M… and something didn’t feel right.  Instead of a peanut, she found… this (Via the Raleigh News & Observer):

[UPDATE: Photo removed at the request of the N&O.  Click the link above to see the image.]

What would you do?

She called Mars (the candy maker), who quickly sent her coupons and an envelope for her to send the mystery object to Mars labs for testing.

Uh…  no.   She actually wanted to know what the object was, and didn’t trust Mars to be forthcoming with her results.

After calling a number of state departments and university labs, the News & Observer got involved as part of their Troubleshooter program.  Most state labs and departments either didn’t have the resources or wouldn’t do the testing, or referred her to private labs (costing upwards of $1000 dollars for testing).

Finally, the N&O talked to the Agriculture Department’s Food and Drug Protection Division.

The director decided to make an exception – as long as the woman agreed not to sue – and got to work.

What tests would you run?  In short order, the director found out what the object was.  Was it tooth?  Bone?  Something else?  If you were the director, what would you do to find out what was in the M&M?  Find out below the jump.

Read more »

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Chemistry Lab Demonstrations: Candy Chromatography

*For more cool stories, pictures, and videos of chemistry demonstrations, click here*

Last lab of the semester today. Next week is the lab final and checkout. This week the students practiced column chromatography. They purified their crude product mixture from last week’s nitration lab. I’ve talked about the theory behind column chromatography before, so I won’t rehash it here in any detail. Suffice it to say that different organic compounds have differing affinities for a stationary phase versus a mobile phase. These differing affinities allow for one compound of interest to be separated from a mixture through the use of column chromatography. Students were aided this week in that their product was bright yellow. They could physically watch it run down the column, then only collect the yellow fractions.

Last lab of the semester means last demo of the semester.  This one’s a do-it-yourself demo, if you’d like.  You can separate the colors contained in M&M shells (or Skittles, or Reese’s Pieces, or Sharpies, etc) through chromatography.  I got my M&M proceedure here.  If you’re interested, other proceedures are available here, and here.   Basic rundown: put drops of water on wax paper, and put a piece of candy on each drop.  Allow for the water to strip the color off the colorful candy shell.  Cut a coffee filter into a rectangle.  Use a toothpick to spot each color onto the coffee filter.  Put the coffee filter into a 1% solution of table salt and allow the water to rise through the coffee filter.  Watch the colors separate like magic!

Couple’a observations I noticed.  Quite interestingly… the stationary phase matters.  A lot.  I started by spotting the colors on my silica gel TLC plates .  I was quite disappointed because the red and yellow both travelled with the solvent front and there was little separation.  I tried several different solvents… no luck.  I also noticed that according to the websites I was looking at, red should have travel the shortest distance.  Then I switched over to filter paper, and all of a sudden I got the results I was expecting.  Who knew?  Also, you should put a crease in the coffee filter before placing it in the solvent.  The paper will start to buckle and it will droop and fall over if it is not creased first.  The more distance you give the colors to separate, the better the results.  I used the largest filter paper we had, and ran the chromatograph twice to get the results shown.

Pop quiz, hot shot: Do you know what the difference between Red 40 and Red 40 Lake are?  I didn’t either.  Turns out… nothing.  At least, not as far as the compound responsible for the hue is concerned.  It’s all in the formulation:

Color additives are available for use in food as either “dyes” or “lakes”.

Dyes dissolve in water, but are not soluble in oil. Dyes are manufactured as powders, granules, liquids or other special purpose forms. They can be used in beverages, dry mixes, baked goods, confections, dairy products, pet foods and a variety of other products. Dyes also have side effects which lakes do not, including the fact that large amounts of dyes ingested can color stools.

Lakes are the combination of dyes and insoluble material. Lakes tint by dispersion. Lakes are not oil soluble, but are oil dispersible. Lakes are more stable than dyes and are ideal for coloring products containing fats and oils or items lacking sufficient moisture to dissolve dyes. Typical uses include coated tablets, cake and donut mixes, hard candies and chewing gums, lipsticks, soaps, shampoos, talc, etc.

There are 5 food coloring agents in M&Ms: Red 40, Yellow 5, Yellow 6, Blue 1, and Blue 2.  As you might expect, green separates into blue and yellow, but surprising the red and yellow of the orange M&M do not separate.  Rather, there is one orange spot with a larger Rf than red.  Brown separates to blue, red and orange.   But it looks like the blue in the blue M&M is a different blue than the blue in the green and brown M&M.

I’ve got lots of pictures from my experience (click for larger).  Note how poorly silica works and how different the Rf’s are between silica and filter paper.  the video is of separating components of felt tip pens, but it’s also neat.

There are no more demos planned, since the lab course is over.  Hope you enjoyed my miniseries.

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