Cleaning for Mg:Ca Analysis: Problems and Solutions

I collected around 40 individual G. bulloides for the first 15 or so depth intervals from the core. I seperated them into two sets of 20 individuals each and carefully crushed the test chambers open in prepartion for cleaning them for Mg:Ca analysis. This gave me 30 samples, which were put into certified metal free tubes on a rack. Even though they were certified metal free, I still treated them to a long heated acid bath to ensure that there were no metals that had collected in them, such as with dust. I then went to Dr. Farmer's lab at Hofstra for the cleaning at around 9 in the morning. The rest of the cleaning work was done inside of a negative pressure hood, to prevent metal bearing dusts from contaminating them. They were then put through a series of treatments, the goal of which was to remove all clay minerals and wash away any Mg or Ca crusts (non-biological) that had accumulated after deposition on the ocean floor. A small amount of methanol (for clays) or acids (for leaching) would be added to the tube and then siphoned off. I also treated the samples to a boiling bath of strong Hydrogen Peroxide, to destroy any organic materials that may also have accumulated, using a sonicator at many steps to aggitate the material. Leaching in a weak acid was the penultimate step before final dissoution. It was after leaching, and this was around 6 or 7 at night, that I realized that the tiny amounts of material were missing, they had either been dissolved at one of the acid steps or sucked up by the vaccuum. That was unfortunate.

So several days later I collected a small sampling of forams, not necessarily all G. bulloides, but similarly shaped and with similarly thin test walls, from a 'practice' jar of washed material. There were four tubes, with around 20 crushed individuals in them each. I then used the same procedure as I had previosuly used to clean them, and after the weak acid leach, they were still there and looked good.
So its possible that I had previously sucked them up with the vaccum, or that I had crushed them too finely, which allowed them to dissolve in the various acids. But it looks unlikely that carefully crushed tests will be dissolved by this procedure, which of course is to be expected, since many other workers have used it with success, including Dr. Farmer.

Now I will have to finish picking the foram samples and clean them, hopefully there won't be any problems with this round.