(I) Background

Instructor: Julian Tyson, Professor Emeritus, Department of Chemistry, University of Massachusetts Amherst
- ResearchGate
The research lasted five semesters, from Fall 2013 (freshman year) to Fall 2015 (junior year).

(II) Fall 2013

In Fall 2013, the research was called First Year Research Experience (FYRE). Our research group did an presentation at Integrated Science Building hall way.
Group member: Lauren Okamoto, Dan Piersiak, Nan Wang
Presentation
Title
- Analytical Chemistry of Arsenic in Rice
Abstract
- In past years, there has been growing concern regarding the presence of arsenic in rice. The EPA has set a 10ppb limit on drinking water, whereas recent tests by the FDA reveal a highest average concentration of 160ppb in brown rice. An article found in consumer reports produced results with varying concentrations of arsenic in rice collected from the same source. Due to this inconsistency, there is a need for an inexpensive and easy way for the general population to test the arsenic levels of the rice they ingest in their own homes. It is unknown, however, whether arsenic concentrations vary between individual grains of rice.

In Spring 2014, the research title changed to Independent Study. A journal article formatted final research paper was written.
Group member: Lauren Okamoto
Research Paper 1
Title
- Determination of arsenic in rice with the Hach EZ testkit
Abstract
- Two experiments to figure out the starch interference to arsenic and to find out trifluoroacetic acid (TFA) extraction had been done this semester. The equipment Hach EZ testkit had been used through the process. For the first experiment, different concentration on starch solution had been made. Compared the normal test results with the starch test results, there were little differences between them but the starch test always resulted in lighter color. Therefore the presentation of starch had a little effect to the final result when the test ran. The second experiment was about using TFA for extracting the arsenic from contaminated rice powder rather than using hot water. The results showed that TFA did a very similar work as hot water because the results that came from TFA extraction were the same as hot water extraction under the naked eye observation.

Still Independent Study. A journal article formatted final research paper was written.
Research Paper 2
Title
- Determination of arsenic in rice with the Hach EZ testkit - 2
Abstract
- Experiments to extract arsenic from 500μg·kg^-1 standard rice by using dialysis bag and to investigate the diffusion rate of arsenic (III) ion were performed. Arsenic species were quantified by both the Hach EZ testkit and atomic fluorescence spectrometer. The rice-outside-and-water-inside 50μg·L^-1 test showed that the Hach test could only showed a result around 25μg·L^-1 although the AFS’s results was around 50μg·L^-1. The second experiment showed that the longer the time, the higher the diffusion percentage.

Still Independent Study. A journal article formatted final research paper was written.
Research Paper 3
Title
- Determination of Arsenic in Rice: Extraction of inorganic arsenic by dialysis
Abstract
- The extraction of arsenic from rice spiked at 500μg·kg^-1 by hot water with the technique of separation of large molecules by dialysis bag was studied. Arsenic species were quantified by both the Hach EZ testkit and atomic fluorescence spectrometry (AFS). The Hach test always showed a lower result than the expected concentration, which was 50μg·L^-1 or 33μg·L^-1. However, the AFS results always showed out a higher number than the expected number, which was 5μg·L^-1 or 3.3μg·L^-1. Spike addition test for AFS showed that the higher results were not caused by systematic instrumental error.

Still Independent Study. A journal article formatted final research paper was written.
Group member: Richmond Ampiah-Bonney
Research Paper 4
Title
- Determination of Arsenic in Rice Extracts: Separation of inorganic arsenic by dialysis
Abstract
- The extraction of arsenic from whole rice grain by hot water, followed by the separation of inorganic arsenic from starch by bag dialysis was studied. Arsenic species were quantified by both the Hach EZ testkit with digital image analysis and atomic fluorescence spectrometry (AFS). The B-value of the color on the test strip was analyzed by ADI and the concentration was determined based on the B-value of the color chart. For rice as received, the Hach test kit showed a result of 66μg·kg^-1 according to ADI and result from AFS justified the concentration was 71μg·kg^-1 which was very close to 66μg·kg^-1. In diffusion test 1, when separation As (III) solution by SnakeSkin® bag, the results from Hach test kit for inside and outside were 33μg·kg^-1 and 69μg·kg^-1 and the results from AFS for inside and outside were 25μg·kg^-1 and 69μg·kg^-1. However, different kinds of dialysis bag could result a different extraction result regardless the extraction time which was not caused by systematic error. The Hach test gave a result of 27μg·kg^-1 and 41μg·kg^-1 for inside and outside the bag in extraction 2, but the AFS gave a result of 61μg·kg^-1 and 63μg·kg^-1 for inside and outside the bag.