Because Organic Chemistry Doesn't Smell Bad Enough

Someone published an Org. Lett. paper on analyzing rotting fish guts. Yeah.

So let's say you're a hungry shark. You want some fish, and you want to make sure it's delicious and fresh and whatnot. How does a hungry shark go about quantifying the following analysis?


I mean, to a shark, it's all good, probably. Dead and rotting? Dory? A hungry shark will eat them all. But those rotting fishies can have some nasty toxic amines in them like putrescine or histamine that can accumulate before you can smell them. So what's a shark to do?

Basically, nothing. The shark's totally fucked in this case.* ** But lucky for us humans, a new technique for detecting nasty amines has been developed using some functionalized polythiophenes. Using a polythiophene that has been functionalized with a carboxylic acid, the Lavigne group has shown in the latest Org. Lett. ASAP that the UV/Vis absorbance profiles of poly(thiophene)s changes when amines form aggregrates with them.

Since every amine is a little different either in size, binding character, or both, the poly(thiophene) aggregates that form will vary from amine to amine. In other words, one amine will aggregate poly(thiophene) such that the polymer molecules are closer to one another, while another amine will space them out more. This "multidimensional response," as the authors call it, changes the solution absorbance profile of the polymer, which can be qualified for each amine. After testing the profiles of different amines, they did a blind test with 97% accuracy, regardless of the complexity of the matrix.


But the best part of the paper was the "proof of concept," or, as I like to call it, "the PI suckered some poor grad student to blend rotting fish guts with trichloroacetic acid." Seriously. They took "fish matrix," which was canned tuna doped with a known amount of histamine (a common biogenic amine found in rotten tuna). They blended it in trichloroacetic acid, centrifuged and added the polymer, then measured the absorbance. Then they repeated it, over and over again. (And you thought you had to do shitty work for your PhD.) Turns out their little polymer makes for a pretty handy amine detector, able to quantify the amount of histamine in your rotten tuna.

It's not without its limitations (what if you have more than one amine? you're screwed; it'd be nice if you could just make a freshness sticker like they do with other meats), but still a neat idea that utilizes familiar chemistry in a really freaking stinky way. Someone give that fish guts guy/gal a medal.

*EDIT: Or not.

**Okay, more relevant example that'll appeal to the retro gaming crowd. Let's say you're playing Final Fantasy III (VI in Japan or if you're a prick) and the world just ended. And you're Celes, and you just woke up a year later on an island with Cid, who's basically your adopted father. And he's really sick after taking care of you for so long. You have to get fish for him to eat, but if he eats bad fish, he gets worse and dies and Celes attempts suicide (depressing!). What do you do? WHAT DO YOU DO? (The real answer is just catch the fast fish, but what if you couldn't tell?)