Technically, today was a disaster in the lab. For the past week I've been 'picking forams' for analysis. We are going to have the carbon-dated. I needed to pick out around 300 individuals of one species, Globigerina bulloides. That was expected to give me around the 10 miligrams of sample that were needed. Six sets, each from a different depth of the ocean drilling project core, were selected, those were the points that we wanted dates for.
So I pulled the specimins, and brought them over to the Hofstra lab, there is a professor/researcher there who has the lab materials and has similar research interests and was kindly enough to permit me to clean the samples there. This is a necessary preparation step before they are sent away to be C14 dated.
I had to put the specimins into a small seive that she had created (six seives, one for each set of 300). These were then split up into two large beakers, which were filled with methanol to about the middle of the seives, which were now partly submerged. These beakers were then put into a sonicator, a device that has a water bath and that vibrates, the vibration will travel through the water to the methanol and mix the methanol with any dirt, clay, sediment, and other carbon bearing materials that need to be eleminated. The non-foram carbon will screw the analysis.
After sonicating for about five minutes, I remove the beakers and take out the seives to let them dry. They dry quickly, because the methanol just evaporates away. I started brushing one of the samples out of its seive, but noticed that a glue used to hold the tiny cloth-like seive screen to the seive had become very soft. The forams were sticking to it.
Crap!
Thats not good! Forams bound up with glue! Thats allways bad no?
I hoped it was just because they weren't completely dry, so I put it down and gave them more time to dry. But it was no good, the glue dried, but at least half of the sample was bound up within it. I brushed out what I could. The Hofstra professor was completely shocked and I could tell that she was mortified and very concerned. She had created the seives herself, and had used them for the same purpose, and nothing like that happened. She speculated that perhaps the glue she used had aged and changed to become unstable somehow. We tried sonicating two seives again, hoping to loosen it completely and set the forams free. I set the sonicator timer for 10 minutes, and it did soften and loosen up, but the foram material was just immpossible to seperate. I though maybe it would be possible to dissolve the glue somehow, or flush it with methanol from a squeeze bottle, to get them out, and then perhaps boil it down on a steam bath, leaving just the forams and vapourizing the dissolved glue, but the glue wasn't necessarily dissolving, just softening.
Fortunately, the professor was able to find a different glue. We pulled one screen off its seive-ring, it had been loosened that much by the sonication, and used this other glue to hold it on. The rings for the seives are some type of acrylic, and the glue was methylene chloride, a glue for acrylics. We were worried that the seive screen itself wouldn't bind, but it turned out to work nicely once she assembled one under a hood. I was concerned that the methylene chloride would react badly with the methanol once we put it to use, so we threw in some sand and tested one out. It worked perfectly, the stuff held together, and the sand grains, a decent enough proxy for forams, didn't stick at all.
So I lost the samples for the most part, and basically have to pick them all again. I only say that it was 'technically' a disaster because I just wasn't too upset over it. Something allways goes wrong, something that forces you to start all over, and usually it happens a few times. Hopefully this is the only time it happens with this C-14 dating project, but who knows.
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