I’m running out of Teeside puns to make so it’s a good thing that this is my last day here! After a great day in Middlesbrough yesterday, I returned this morning to the lab to continue my work here. If you’ve been wondering what exactly I’m doing in the lab, wait no further! I’m going to give you a brief crash course on some of the stuff that we do in the lab.
Firstly, welcome to the lab:
Remember to fill out your risk assessment form and put on your safety gear including: gloves, goggles, a lab coat, closed toed shoes, and a smile!
Here’s the view from the lab. We’re on the 10th floor so we’ve got quite a nice view of the surrounding area.
The project I’m working on is studying some of the Roman Leather we frequently get at Vindolanda. While these studies are quite preliminary, we are looking to answer questions such as whether one can differentiate between various hides, what type of chemical signature remain on the leather and whether this can tell us the type of tanning processes used by the Romans, and even information about the conservation process and its effect on ancient leather.
The first thing we have to figure out however is what kind of information we can get from the leather. After some research, we’ve started by looking for specific chemicals that indicate the type of tanning chemical used. In general, these chemicals are called “tannins” and bind to the collagen in the leather to create that shiny and waterproof material that your jacket/purse/wallet/shoes are made out of.
The first step is to extract these tannins from the leather. Because they’re quite tightly bound, this can be quite a challenge and we’re trying several methods to see which is the best.
The second step is to analyse these tannins. There are several options to do this but the two that we’ve chosen are High Performance Liquid Chromatography (HPLC) and Attenuated Total Reflection Infrared Spectroscopy (ATR-IR). Try saying that 5 times! While I’d love to explain these methods in great detail, I’m going to focus on just HPLC because it’s probably the most useful.
The word “chromatography” is used in chemistry to indicate a technique that separates a mixture of compounds. The way it works is actually quite simple and I’m going to explain it in terms of something we can all understand: candy (or “sweets” in British)
Imagine that there are 3 people enter the sweets aisle in a supermarket at the same time. Because everyone is different, one person (Alicia) is incredibly health conscious and doesn’t really eat sweets, another (Bob) likes some chocolate on the odd day, and the last one (Carol) has had three cavities in the past week. As the three walk down, Carol is going to immediately stop to look at the first sweet she sees. A little further down, Bob tries to keep going but gets distracted by his favourite Kit Kat. Perhaps today is a cheat day…Alicia is laser focused with incredibly discipline and just shoots down the aisle and out the other end.
This is the basic principle of chromatography. We push compounds down a column (aisle) and based off of their chemical properties (sweet preferences), they spend differing amounts of time in the column. Thus, a mixture slowly separates into components based off of the amount of time they take, a metric we call “retention time.” We can tweak a few other parameters to improve the separation as well. HPLC just states that this process occurs using liquids under high pressure.
That’s all the chemistry for now! I hope you have a better grasp of some of the analytical techniques that we use. If you’d like to learn more about some of the other things I’ve been doing or have some questions about this post, comment below. Tomorrow, I return back into the mud and become as Justine has termed it, a “Trench Troll” once again. Until then!