Yesterday Kim and I drove six hours south to Rovaniemi. This small city is just a few kilometers south of the Arctic Circle. In fact, Santa Claus Village straddles the Arctic Circle, and all Finns know that this is where Santa lives. Wow, and all this time I thought that North Pole, Alaska (just east of Fairbanks) was the Santa Claus capital!
Rovaniemi and METLA
We came to Rovaniemi to analyze the gas samples we have been collecting. Kim has run out of vials for collecting samples, and she also has a lot of samples that she collected this spring before I arrived. As the laser has not turned up yet, she decided to change plans and take care of some of the "lab work."
Rovaniemi is one location of METLA, which stands for Metsantutkimuslaitos, otherwise known as the Finnish Forest Research Institute. This is the affiliate agency for Kim's work in Finland, so she uses lab space and equipment here to analyze her samples.
The main METLA building, the Finnish Forest Research Institute in Rovaniemi. Kim does her lab work here.
It's All About the Gas
Just turning on the gas chromatograph is a lengthy process. Kim is using helium as the carrier gas to analyze her samples. The helium flows through the machine, and carries a portion of the gas sample through the column. Using helium will not mask or affect the gases (carbon dioxide or methane) that she is measuring.
Gas cylinders in the gas chromatography room. From the left: argon, hydrogen, helium, compressed air. Kim uses the helium as the 'carrier gas' in the gas chromatograph.
The Column
So how is the gas in a sample separated into its various components? I will be writing in detail about this process during these next few days. However, the main idea is that some of the sample gas is injected into a column, which looks like multiple loops of wire.
The column inside the gas chromatography machine is specific to the kind of gas you are analyzing for.
A gas sample is made up of different molecules. The molecules that Kim is measuring in her samples are the CO2 and CH4. Each type of gas molecule is a specific size and travels at a specific speed through the column. Because the molecules are different sizes traveling at different speeds, as the sample travels around and around inside the coiled column, the different types of gas molecules will start to separate from each other.
A detector records the electrical signal (number of electrons) of the gas molecules hitting it after they exit the column. As the gas sample has been separated into its different molecules (by traveling through the column), the electrical signal will be specific to a particular gas. On the computer screen, this electrical signal will show up as a peak. Different types of gases show up on the screen at known times. For example, the carbon dioxide peak shows up at 1.5 minutes after the gas sample is injected into the column.
The large peak on the left represents air (mostly nitrogen) in this sample. The smaller peak on the right shows the amount of carbon dioxide in the sample. We know it is carbon dioxide because it shows up at the 1.5 minute mark.
Change of Subject
Enough gas chromatography for one day! There will be more to come, but I thought I would add a note about the weather I have been experiencing. For the past week, Kevo has been really sunny and warm. It has been record-breaking warmth in fact, in the high 70s (Fahrenheit). Here in Rovaniemi, it has been equally hot and sunny (perhaps even warmer). People here are just amazed. It has been so warm and sunny that the Finns are shaking their heads and saying that the rest of the summer is sure to be cold and wet!
However, there was a huge downpour this evening as I worked with the gas chromatograph. A little while later, this is what I spied as I walked back to my lodging!
These are the biggest chunks of hail that I have seen in a while. That is a regular-sized chapstick for comparison.