Category Archives: Water Analysis

FT-IR scans from Alex

Alex uploaded the data sets to FigShare per my request. Here is her notebook entry regarding the subject, here is the data set on FigShare:

FTIR spectra DDW, DI, D20 raw data 2-2-2012. alexandria haddad. Figshare.
Retrieved 21:12, February 04, 2012
hdl.handle.net/10779/9a949ce6c387087d66c15f0de1b81b1a

And here is the jpeg of the scans:

FTIR DDW, DI, D20 2-2-2012. alexandria haddad. Figshare.
Retrieved 20:37, February 04, 2012
hdl.handle.net/10779/dbccbe502b5449477dd268436b03222d

 

FT-IR Training and Experiments

Since mid December, I’ve been urging Alex to set up FT-IR training with Stephen Myers and being the go-getter that she is, she has set up a few training sessions. You can see her notes from that here.

I spoke with her at the beginning of the week to try and plan the future of these experiments. We have a couple of experiments that we would like to try out which wouldn’t be all that time consuming, and I’m leaving her in charge of all of it (she’s big time now!).

Yesterday was just step 1. We went to examine 4 samples. We wanted to analyze (3mL of each): DDW, D2O, DI, and DDW + 1uL of D2O (which was roughly equivalent to the standard mean ocean water).

I haven’t looked at the data in any real detail yet, but by eye the DDW and DI looked very similar, and there was almost no difference between that and DDW+1ul D2O (but I thought it was slightly discernable). Because of this we tried 3mL of DDW with 70ul of D2O added (which is roughly 2% by volume D2O), and this was obviously different in profile (but barely). As per usual, the pure D2O sample was very different.

Hopefully Alex will get the data on FigShare today (I could do it myself easily, but I would like her to experience the awesomeness).

Mini rant in 3… 2… 1… I gotta get her to be on top of her notebook a little better. I keep telling her to notebook frequently about everything, and that she just needs to get into the habit of doing it. She agrees but then doesn’t notebook. Grrrr… I was hoping to do this post yesterday but alas Alex didn’t post until after my bedtime so here it is now. Once she enters the lab I’ll be all over her like a tiger on a gazelle licking lilacs in the wilted meadow of frozen tundra. With regards to posting to figshare, of course. Rant over.

Anyways the plan for the project is as follows:

  1. Understand the spectroscopy results as they correlate to the physical properties of the water molecules (H2O and D2O and HOD). This will be major literature searching on Alex’s part with aid by myself.
  2. FT-IR analysis of D2O/H2O mixtures. Koch and I think there could be some really interesting results/studies in the mixture range around the amount that is naturally occurring. So I want to do a broad study of different D2O amounts in DDW from 0 up to 100% so we can understand how the peaks shift from H2O bonds to DOH bonds to D2O bonds.
  3. FT-IR analysis of DDW time dependence. D-exchange is a real thing. It happens all the time and rapidly, but how long does it take for DDW to reach the levels of deuteration of naturally occuring water? This is something I’d like to know. And something we hope to find out.

So with all that said, I’ll be linking to Alex’s notebook with regards to these experiments in the future and add some minor notes myself here. In the meantime I will just twiddle my thumbs until those data sets get uploaded to figshare…

FT-IR Preplanning Thread

I want to get some ft-ir studies off the ground. First experiment would be to just see if FT-IR spectroscopy reveals differences better natural water, DDW, and D2O. Comment for ideas…

1st Try at FT-IR Spectroscopy

I’ll explain the idea of these new experiments in more detail later, but I had this data from today and wanted to get the information in my notebook. There is an Ft-IR spectrometer at CHTM (actually 2) and we were granted permission to use it by Dr. Sanjay Krishna courtesy of Stephen Myers and my buddy John Montoya.

The purpose is to figure out a way to accurately measure the amounts of D2O in H2O or H2O in D2O. Today was just about seeing whether we could conduct these experiments with the equipment we have (plastic macro cuvettes). The answer is no, but the experiments are still worthwhile.

We ran 3 experiments: (1) nothing in the sample chamber but air, (2) an empty cuvette in the beam path, and (3) a cuvette with pure H2O (deuterium depleted water). The spectrometer has the capability of subtracting (dividing) out the background, sort of like blanking a solution when dealing with a nanodrop. So we used the empty chamber and the empty cuvette experiments as background readings to test the H2O. Here is the data:

The following graphs are % Transmittance (y) vs Wavenumber (x).

 This is the empty chamber sample.

This is the blank cuvette experiment.

This is the same experiment, except that in this graph the air background reading has been divided out.

This is the DDW sample with the cuvette reading divided out.

The data isn’t reliable because you can see in the last data set that there are transmittance numbers above 100%. Right now I can’t explain the how’s and why’s because I don’t know all that much about the equipment or the process, but in this range we were getting rather low transmittance anyway so I wouldn’t expect to get accurate results.