Over the last year I’ve spent a ridiculous amount of time fighting with the machines that are meant to help me analyse soil and vegetation chemistry. One is our Carbon and Nitrogen analyser – you put a small amount of a dry soil or vegetation sample into the machine which burns it at a high temperature, releasing the carbon and nitrogen as gasses. The gasses are filtered to remove other elements and then picked up by a detector. At least that’s what it should do, but we’ve had persistent problems with the nitrogen readings. We’ve had maintenance people come repeatedly to service it. The analyser will then usually work for a few samples before the results become unreliable again. Two weeks ago a new person came to check out the machine. As is common with these things, the CN analyser worked pretty well while he was there and we managed to get a few results. Unfortunately, when we tried to run more samples the next day, the CN analyser went back to its old tricks. Even the tech support people don’t understand what’s going on and are running out of ideas to fix it, so it looks like I’m going to have to find another lab that might be willing to let me run my samples. It’s a very frustrating loss, but it doesn’t seem like there is much more I can do and I need to get some results soon!
The second machine that has been causing problems is a Skalar continuous flow analyser. Basically, you extract nitrogen and phosphate from soils, run them through the machine with various chemicals which cause a colour change reaction, and the machine calculates the amount of extracted N and P based on intensity of the colour produced. Over the last year I tried to run samples on the skalar at least a dozen times. I got it to work and produce reasonable results only once in July, and when I tried again the following day, it failed. Sometimes the lab was too hot, sometimes parts would break, and sometimes I just couldn’t figure out what the issue was. Every time I tried again, I’d have to spend a few hours cleaning the machine and making fresh reagents only to find that something else was wrong. Finally, last Monday, a former PhD student from our lab came to the rescue. She had been doing a fellowship in Australia and is about to start a post doc in Manchester, but was able to spend a bit of the time between the two helping me out. We managed to fix a couple of broken/loose pieces, adjust a few settings, remake reagents, and luckily the lab stayed cool. This meant that instead of another week of data analysis, I ended up analysing a few hundred samples and actually got good results with reasonable replication! I can’t tell you how exciting it is to finally have the machine working, and to have had help on hand from someone who had used the machine before. It was definitely a much-needed lab win.
I hadn’t expected to spend the whole of last week in the lab though, and it was a big rush to get everything done as I had a flight to catch on Friday – for my first holiday since starting my PhD! An unexpectedly hectic week followed by blissful relaxation is my excuse for not posting in a while, by the way. The victory in the lab has made me feel much more deserving of the vacation that followed. I’ve still got another week to go, celebrating Thanksgiving with my family in the US, but I’m already feeling refreshed and much more ready for the next data analysis blitz. Which is good news considering I now (finally) have a sizeable stack of soil chemistry data!
Direct effects 