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Arsenic detection in well water with spectrometry

by LEGOnauts |

Arsenic detection with spectroscopy lab

Objective

Create a lab for chemistry students where they can create their very own arsenic sensor using the DIY spectroscope. If an effective test can be produced, the number of households that have tested their water for arsenic can be increased dramatically.

Materials

  1. Black Cardstock
  2. Clear Tape
  3. Scissors
  4. Exact-O Knives
  5. Discs
  6. Nail Polish Remover
  7. Cuvette
  8. 405nm Laser

Safety Precautions

  1. Please wear goggles when using the chemicals in water and the lasers as the lasers and chemicals can damage your eyes and could be sprayed into your eyes.
  2. Please wear gloves when handling chemical liquid elements, so if they get on your hands, you are protected.
  3. Please be careful and cautious when using Exact-O Knives and scissors from its blades. Do not hand the Exact-O Knives or scissors directly to your partner(s), please put it on a platform for them to grab it.
  4. Please do not smell any nail polish remover or chemical elements.
  5. Please do not consume any of the testing sample liquids.

Disposals

The remainders of your discs should be properly disposed of by recycling them. Please do not dump out any liquid samples with hazardous chemical elements in them down the sink, toilet, or anywhere that leads into the sewage or into your body.

Procedure

SpecBox Instructional Video:

Procedure for the Outside of the SpecBox:

1. Cut out the outline of the spectrometer/spectroscope out of the black cardstock. Make sure you cut out the solid black line and not the dashed lines inside the outline.

3. Please make the slits where they are on the outline by using Exact-O Knives.

4. Once the slits are cut in the black cardstock, please fold along the dashed lines that were in the outline, except for where you are going to attach the disc and attach all of the folded areas with tape.

5. After that, attach that to the areas where you have the squares to attach the discs and ensure that there are no fingerprints on your disc before you attach it.

6. Once attached, fold the pieces with the discs to the rest of the spectrometer and attach it with tape.

7. Then, align the slit from the holder to the slit on your spectrometer, then attach them with tape.

Procedure for the Cuvette Holder:

  1. Cut out the outline for the cuvette holder from the black cardstock.
  2. Cut out the slits in the holder using and an Exact-O Knife, respectively.
  3. Then, please fold the cuvette holder along the dashed lines and ensure that your cuvette holder firmly holds the cuvette.

Procedure for Disc:

  1. Cut the disc into four equal parts and to use another Scissors
  2. Split the disc vertically in half
  3. Then, please use the nail polish remover to remove any silver lining off of the disc.
  4. Once the silver lining is removed, put your disc up to a light to ensure that you can see a light spectrum which ensures vertical grating.
  5. Then, cut out where you see the spectrum in a square.

Testing Procedure:

When you have finished creating the spectrometer, take your sample fluid, laser, and spectrometer and hold your laser up to the sample fluid that you have placed in the holder and look through the disc to see the spectrum of the chemical that is present in the sample fluid.

Spectrums:

Arsenic

Assignment

Go home and take a sample of your tap water from your house or we'll put it into your cuvette. After that, attach it to your phone and observe whether the spectrum for Arsenic is visible.

If so, please bring in your results back to school and we will help you figure out how to treat your water and contact the Public Health Labs and Water Treatment Facilities.



response:480


2 Comments

Hi, this is fascinating, do you have a link to a study you're working from? What concentrations do you think you'd be able to detect, and do you have an example of this working that you're looking to reproduce?

Also I'm curious what a white laser is! What wavelength range is it?

Thanks for posting!

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This is really exciting. Are you planning to do a flame test for this? (I'm pretty unfamiliar with arsenic)

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