Solid Phase Extractions

It has been a while since I have written a science post -- so I want to share with everyone how we are actually processing some of the water while we are in Alaska.  I will end with some wildlife pics, I promise!

We are using a common method to isolate dissolved organic matter from water called solid phase extraction (SPE) cartridges.  Each of these cartridges is a plastic collumn with a small amount of porous material at the bottom that bonds to organic material (ours contain 5g of solid phase, but they come in all different sizes). 

Our extraction set-up!

We have developed a system of tubes that allow us to pass water from the 20L carboy into the top of the cartridge.  As the water drips through the solid phase, the organic matter bonds to the material and is removed from the water (a process called "loading" the collumn).  Since no solid phase material completely removes 100% of the organic material from the water, we are using 2 types of solid phase material: C18 and DVB.  These two types of solid phase bond to slightly different types of organic matter, which will hopefully give us a representative picture of organic matter composition.

As the organic matter is loaded onto the collumn, a dark band appears at the top of the solid phase.  Throughout the process we monitor the water that comes out of the collumn to determine when a significant amount of the organic matter is no longer bonding to the collumn and is actually just flowing through the solid phase (this is known as "break through").  At this point, we stop dripping water through the collumn and it is time to get our organic matter out!

Two completed C18 Cartridges after 15L of water were passed through each collumn

In order to remove the organic matter from the solid phase material in the collumn, we need to pass some liquid through that the organic matter will be more soluble in than water - which will allow the organic matter to dissolve in the liquid and be released from the solid material.  In our case, we use methanol to flush out the organic matter.  It is actually quite fun to watch the band of material moving down the collumn as we pull the methanol through!

The beginning of the extraction

The band of organic matter is moving down!!

... almost to the syringe...

Here it comes!  Look at that golden color :-)

... and out comes the organic matter!

At the end of this long process, we have a gorgeous amber brown material that will later be dried down to a powder for all of my experiments at OSU!!

The syringe at the end of the extraction full of our precious organic matter

Okay, so now for the promised animal pictures :-).  Allison and I headed out a couple of days ago to the Oksrukuyik Creek (pronounced Oxy-curic) to collect more water.  As we were driving, we spotted a muskox, which looked like a mass of fur moving along the river!

Unfortunately the muskox is a little out of focus, but he looked like a walking long haired wig!

While scoping out field sites we also spotted an Alaskan Lake Trout!

The first few days at Toolik~

I would like start with a little background on the origin of the trip to Alaska.  For my graduate research, I am interested in brominated flame retardants.  These compounds are included as components of many common household goods including fabrics, foam, and electronic components.  These compounds are very important in preventing and slowing the spread of fires.  However, as with any compounds we use on a daily basis - their entry into the environment is inevitable.  The most toxic forms of brominated flame retardants have recently been banned, yet some remain in use.  My question is: what happens to these compounds when they enter the environment (eg. what is their environmental fate).

So, your likely question right now is: "Then why go to the arctic?"  It turns out that brominated flame retardants are ubiquitous in the environment and are even transported to the poles in the air.  Therefore, I headed to the arctic to see how these compounds break down once they enter the aqueous environment.  Since this field season is pretty short (we will be at Toolik for 11 days), our focus is to collect water and preserve it for experiments back at OSU.  I am interested in the dissolved organic matter in the water.  When dissolved organic matter is exposed to light, it releases molecules that can interact with other compounds to break them down into smaller components.  This may be benificial in many cases.  However, with brominated flame retardants, the degraded form of the compound (ie. the daughter products) may be more toxic than the initial compound!  In this study I hope to identify these daughter products as well as determine how they form.  Over the course of the next 11 day, Allison and I will be collecting and filtering over 200 L of water.  We will ship 160 L of the filtered water back to OSU for processing, while dissolved organic matter will be extracted from the remaining water.

Okay, I know you are probably thinking: "enough already, get to the pictures!"  So here is the story for the past few days.

My labmate, Allison, and I arrived in Fairbanks at 1am on Monday morning.  We hopped a taxi to University of Alaska, Fairbanks and dragged ourselves up to the dorm for the night.  We had one day overlap in Fairbanks, during which we picked up some last minute supplies and took a several showers (to make sure we are squeaky clean before our venture up to the North Slope).  On Wednesday we woke up at 5am to a gorgeous and bright morning.  At this point Fairbanks does have darkness for part of the night, but I can attest to the fact that the sunrise definitely occurs well before 5am :-).

While on the Dalton, we passed over the Arctic Circle and (of course) had to stop to take a photo!

We had gorgeous weather when we first arrived.  Since it is late season, the evening turns dusky and the Brooks Range appears pink in the light.

The Brooks Range cast in a rosy glow :-)

Tent city as seen from the far side of Toolik Lake.  Allison and my tent are the two to the furthest right in the photo

We have hopped right in with filtering and collected 100L of water from Toolik Lake our first morning at camp.  Now to get it all filtered...

The filtration set-up with our trusty little parastaltic pump!
We pass the water through a coarse pre-filter and a 0.45um
filter.

A close-up of our work horse pump and the pre-filter for the water.