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Joe Zibley-Analytical Problem:I-131 in Japanese Milk Supply

The recent disaster at the Fukushima Daiichhi nuclear power plant released many radionuclides into surrounding area. One of the main concerns after the evacuation of the area was radiation contamination of the area's food supply. Milk from Japan has shown higher levels of radioactive I-131 than is allowed by law. The FDA has even banned food products from Japan including milk. How can I-131 be detected in milk and the radiation levels quantified in as quick and accurate manner as possible? This is an important problem to solve because radiation levels for the public should always be kept as low as possible. More specifically I-131 can cause thyroid cancer especially in infants and young children. The central hypothesis is that I-131 in milk will have higher radiation levels closer to the nuclear plant. The analyte is I-131 in milk and the matrix is the milk and any contaminates in it.

Wakeford, Richard. And now, Fukushima. Journal of Radiological Protection [Online] 2011, 31, 167-176 http://iopscience.iop.org/0952-4746/31/2/E02/ (accessed Sept. 20, 2011)

Lubick, Naomi. Little Radioactive Material From Fukushima Reached Europe. Chemical and Engineering News [Online] 2011 http://pubs.acs.org/isubscribe/journals/cen/89/i34/html/8934scene.html (accessed Sept. 20, 2011)

UV Vis Absorption Spectrum
5b. I-131 won't absorb in UV-Vis spectrum but Iodide will react with starch, specifically amylose, to give a blue amylose-iodide complex. This method has been used but it seems that it is normally used to find the concentration of amylose as opposed to iodide. The iodide has a complex equilibrium with I(2) and I(3)- based on its concentration in the solvent. Ideally the equilibrium would be pushed all the way to 100% I(3)- because that is the species that forms a complex with amylose. This will not be a easy and straightforward way to find I concentration but it should work. Also I do not think this method will differentiate between I-131 and any other isotope so it would only really confirm the presence of Iodide in milk sample

Important Steps
1. dissolve amylose in 90% dimethyl sulfoxide and 10%water
2. isolate I-131 from milk samples
3. add I-131 and dilute to 10% dimthyl sulfoxide and blue amylose-iodide complex forms

maximum wavelength: 600nm with dimethyl sulfoxide
molar absorptivity: varies based on solvent concentration but mean value is 26,119(L/mol*cm)

Question 3 was originally searched for using CHEM 4101 library page. There weren't any promising papers and I wasn't expecting to find uv-vis info regarding I-131 so I modified search to looking for starch-iodide uv-vis information.

Knutson, C.A. A Simplified Colorimetric Procedure for Determination of Amylose in Maize Starch. Cereal Chemistry. 1985, 63, 89-92.


Similar Analytical Problems

a.Justin Michael- Boron in Groundwater
He is concerned with figuring out how to best remove boron from the environment using different sorbents to reach standard limits for drinking water. The analyte is boron, matrix is groundwater samples so likely very complex. Relevant because both are concerned with quantifying an element that is potentially harmful to people.

Osman Janshed- Detecting Prions
He is concerned with detection of prions in food before people eat them. The analyte is prions in a matrix of meat. It might be a little stretch to say they are similar but we discussed that we may have similar matrix with them both being food products.

b. Boron could have a similar study as I will need to do a study of I-131 concentrations based on distance. Boron may find this useful to see how groundwater treated in one place effects groundwater in nearby areas. Also for me studies might be useful to collect data on how cows are housed(inside/outside), food storage(inside/outside), milk processing(I-131 in large milk collection tanks, etc...). negative control for myself could be done in similar parts of Japan that have not been affected by Fukushima, any historical data of this sort for Japan.

c. My studies will probably not be similar to Osman's because our similarity is with the matrix. The studies listed above besides by distance will be unique to only my analytical problem.

Blog 6 Chemical Structures

View image

I have not been able to find a definitive form of I-131 in milk but I know I2 is a stable and common form of Iodine. In studies quantifying iodine concentrations in milk they do not specifically say what from it is in. As far as detecting I-131 with a geiger meter the form of I-131 is irrelevant since no sample prep is needed for this type of detection.

Perkin Elmer sells radiochemicals including I-131. The catalog number for the most active sample is NEZ035A025MC which is 25mCi of NaI-131 in NaOH. The price isn't listed on the website.

Dahl, L;Opsahl, J; Meltzer, H; Julshamm, K. Iodine concentration in Norwegian milk and dairy products. British Journal of Nutrition 2003 90, 679-685

Comments

Blog 13? -1 pt

Blog 9. The answers seem right. Is GC used for I2 or a derivative?

Blog 10. Good answers.

Blog 11. Will you be detecting I-?

Blog 11
1) I believe that CZE and MEKC would work for my analytical problem. Gel electrophoresis and cIEF wouldn't work since they are mainly for large biological separations like DNA/proteins.
2)I think that CZE would be best since the paper I found used CZE. MEKC would only be better if the I was uncharged.
3)Buffer is phosphate, borate, SDS(pH=2.3) and uncoated capillary.
4) Detector is ICPMS because it is the only detector that can differentiate between isotopes. This analysis will work but I am not sure that CE at all is necessary since I have seen papers specifically for I in milk using ICPMS.

1) ICP-MS
2)Revy Saerang(titanium dioxide), heidi nelson(zinc oxide/titanium dioxide), and sara baldvins(arsenic in groundwater) are all planning to at least use ICP-MS for part of their problems.

Blog 9: Separations

1)GC has been done for milk samples
Reverse Phase HPLC
SEC: complex iodine with starch and then separate with SEC- used successfully with seawater and urine samples
Ion Exchange- could work if you put a charge on I

-chiral chromatography is not helpful because I has no chirality
-affinity chromatography is not useful because it is mostly for biological separations

2) i believe GC would be best since it has been done successfully with milk samples

3)Rxi®-5Sil MS Columns from Restek

http://www.restek.com/catalog/view/7718

4)inert gas- Helium/Argon

5)Electron Capture Detector-the paper that I am referencing used this detector so we know that it is a suitable detector


Shelor, C.P.; Dasgupta, P.K.; Review of analytical methods for the quantification of iodine in complex matrices. Analytica Chimica Acta. 2011, 702, 16-36.

Good answers.

Blog 8: Sample Prep

1) Strongly acidify milk using sulfuric acid, let stand, filter

2) treat filtrate with iodate

3)treat with acetone to form iodoacetone

4)hexane extract analyzed by GC-ECD

-to detect elemental iodine skip iodate step

Shelor, C.P.; Dasgupta, P.K.; Review of analytical methods for the quantification of iodine in complex matrices. Analytica Chimica Acta. 2011, 702, 16-36.

Good answers for blogs 6 and 7

BLOG 7

4a) The analyte is I-131 which has a nominal mass of 131amu and an exact mass of 130.9061246amu.
b) The ionization source could be electron impact or ICP. In the literature most of what I have seen uses ICPMS. ICPMS is probably best because it will atomize and ionize the samples.
c)The best mass analyzer to use would be a quadrupole but a TOF would probably work too. The most important aspect of the mass analyzer is that it needs to very accurately report the mass. For this experiment the structure of compound is irrelevant because we are just looking for I-131 so accurate mass is most important.
d)I couldn't find a spectrum of I-131. MS using iodine isotopes seems to normally report the ratio of one isotope to another instead of showing the actual spectrum. The spectrum would have a peak around m/z=131. There would also likely be peaks of the other isotopes around I-131 peak.

masses: http://physics.nist.gov/cgi-bin/Compositions/stand_alone.pl?ele=&all=all&ascii=html&isotype=all

Dahl, L;Opsahl, J; Meltzer, H; Julshamm, K. Iodine concentration in Norwegian milk and dairy products. British Journal of Nutrition 2003 90, 679-685

Both answers for Blogs 4 and 5 are good.

Iodine can be detected in iodinated thyronines, which are the hormone from the thyroid, when reacted with fluorescamine. The solution shows max wavelength at ph 9 with the fluorescamine in a 40 fold molar excess. The maximum wavelength of excitation is the mercury line at 365nm and the emission maximum wavelength is at 490nm.

This derivatization would need to be done in 2 steps. The first to iodinate the thyronines with I from milk samples and the second is to add the fluorescamine to get fluorescence. Also I do not believe that this method will differentiate between radioactive isotopes and other isotopes. This means that this method could possibly be useful to quantify a total amount of I but not be useful at all to detect I-131.

This method is probably not ideal for our detection of I-131 but it is interesting because the thyroid is where I-131 would accumulate in the body possibly causing cancer. This method could provide very interesting analysis of the I content of the thyroid in affected people or possibly cows assuming I behaves similarly in them. It could be more useful in a related study but not for ours particularly.

Reiterer, F.; Nachtmann, F.; Knapp, G; Spitzy, H; Fluorimetric Determination of Tyrosine and Iodinated
Thyronines as the Fluorescamine Derivatives. Mikrochimica Acta 1978, 1, 115-124.

Studies To Investigate Problem

1A)measure I-131 levels and map as function of distance from Fukushima power plant

B)for each measurement collect information on food source(type/storage location), etc) and cows(breed/location/sale of cows between farms, etc)

C)determine normal background levels for I-131 in regions milk(either from similar region to Fukushima area, or historical data)

2) The EPA has done I-131 measurements in US milk since 1978. For California milk the highest levels where after Chernobyl which were 1.39Bq/L. Obviously the levels in Japan will be higher but the EPA has already demonstrated the ability to measure low levels of I-131. The lowest levels that were not less than the blank were on the range of 0.003Bq/L. These would represent a low estimate of the minimum levels possible but will prove useful in determining a normal background for I-131

http://oaspub.epa.gov/enviro/erams_query.simple_output?Llocation=State&subloc=CA&media=PASTEURIZED+MILK&radi=Iodine-131&Fromyear=1978&Toyear=2011&units=SI

I found our analytical problems similar in nature because we are both require to use some type of coupling reagent that will make our analyte detectable in the UV/Vis spectrum. Also both of our analytes in question are found in an aqueous matrix.

Our problems differ however, in the fact that his analyte is a radioactive element, while mine is a low molecular weight, anionic chemical compound.

I feel as if there is quite a bit of similarity between our two analytical problems for the following reasons.

Most noticeably, we are both required to find other types of reactive species that will couple with our analyte in question, in order to allow it to absorb in the UV/Vis spectral range.

Also, both of are matrices are aqueous and will most likely have noise from other dissolved compounds that are present.

We differ, however with the type of analyte in question. While yours is a radioactive element, mine is an anionic short chained polymer/oligimer.

Great posting!