June 24: Top of the ninth

Posted: Fri Jun 25, 2004 6:07 pm

Also Penney’s 27th birthday! Everybody, now: “Happy birthday to you! Happy birthday to you….”

Penney suits up for sampling at bugging hour. (Anymore, it’s always bugging hour!)

Today we started our final experiment; we are in the home stretch! With several hours between sample points, and no experiment to prepare for tomorrow, the pace of our work slowed dramatically; we can breathe again. Smile

There was some drama this morning when the gas chromatograph started to give funny results (i.e., peaks missing or peaks in funny places). The culprits were pieces of septum (a foam-like cap through which the syringe is pushed just before injecting it into the column). Apparently, small bits of septum had become dislodged and were gumming up the works. More clever observations and deductions on the part of Penney, Yo, and Amanda.

The glass column is skinnier than a piece of spaghetti. If you look closely at the column on the left side of the photo, you can see the discoloration where the septum was lodged.

I spent the day taking apart the lake reactor (a very satisfying chore as it gave me another chance to put on the waders and jump in the water), and transferring hexane (with pollutants) from the mixing vials to the smaller sampling vials.

Interesting Facts to Make You Smarter
Hexane is less dense than water, so floats on water. No, it doesn’t matter how much hexane, doesn’t matter how much water.

Because the pollutants we are studying are hydrophobic (hydro – water and phobic – fearing), when we add the water and hexane together, only the pollutants at the surface of the water slip into the hexane. We use a device called a vortexer to thoroughly mix the water and the hexane, allowing as much of pollution as possible to transfer to the hexane. Trouble is, like mixing oil and water with a little bit of soap, when you mix hexane and water and dissolved organic matter, lots of little bubbles form; impress that special someone by calling this kind of mixture an “emulsion”.

How do you separate an emulsion? If you put the mixture into freezer, the emulsion will separate. As water freezes, it forms tightly-packed crystals, pushing out oil or hexane bubbles.

On a lighter note:
We enjoyed a very pleasant birthday dinner together and a game of Scrabble afterwards. Yo, who does great impersonations, kept invoking the Coneheads: “Scrabble, scrabble… Scrabble, scrabble”.

A couple of friends from around the camp also popped by: one of whom came to say goodbye (he’s leaving tomorrow and won’t return until we’re gone), one of whom came by to say hello (she arrived yesterday).