Public Lab Research note


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Putting together H2S Test Kit

by megan |

Here is a little narrative about how I put together the test kits to send out to Josh at San Juan Citizens Alliance.

Materials

Note: All materials except for the photo test strips and black photo bags can be procured at your local hardware store. Check previous H2S postings to find out where to get photographic materials.

Pre-prepared photo test strips Black photo bags Masking Tape Duct Tape (I like the new kind that is not sticky, it is a dollar or two more, but it doesn't gunk up your stuff) 12 or 14 gauge wire that is used to hang ceiling tiles (any wire will work for the stakes, however I found this to be the cheapest) Black Sharpie Blue Sharpie Mason line string (any string will work, I just used this because I had it and it is easy to spot in the field) 3/4" Black PVC, this is used for plumbing. Rachetting PVC Cutter (This is not necessary, you can just use a saw, but as a tool junkie, I have to say this is one of my new favorites, it is amazing, only 12$ and cuts through PVC like butter, with no mess) Wire Cutters Measuring Tape A dark room (not a photographic dark room), just a room that is dark

First, I cut all of the 3/4" black PVC into 4" pieces, I cut 60 pieces for this test.

Then to close one end (to mimic the photographic containers) I put two pieces of duct tape, in an X formation, one over another on one end.

Then I put a piece of masking tape each and labeled according to the requirements of the experiment, for this particular experiment we are doubling all containers, in order to run a week long test and a month long test. So it was useful to have two different colored sharpies, to make this distinction.

Then I cut 60 pieces of wire approx. 6-7" long I then attached one piece of wire to each container with duct tape.

I left two containers without wire, they will be holders for the photo paper, a control that will not need a container on site.

I then taped each of the pairs of tests together, that way on site, it will be easy to place them.

I then prepared three photobags, I labeled them 1, 2, 3 due to the needs of the experiment. And placed the 8 properly labeled pairs of containers in each bag.

Now we are ready to put in the photo paper. I am using photopaper that was prepared by Sara, two months ago, and stored in a black photobag since. Since photo paper is not super sensitive, it is not necessary to use a dark room, I find the best thing to do is work at night with no lights on, so you have moonlight to work by. But since I had to do this during the day, I just went into a bathroom with no window and no lights on and left the door open a crack so I could see what I was doing.

I cut each strip into about 1-2" sections, and loaded each section into the containers.

After the containers where filled, I placed them, open end down (so when the bag is opened on site they will not get any direct sun light) once all the containers were in the bag, I folded it over and sealed it with duct tape.

I then did this same procedure for the remaining two bags.

Done with that!

I then prepared the control canisters in the same way and taped up the bottom (this tape will be removed on site, I just needed something to keep the light out, because they didn't get a bag)

I wanted to include an easy measuring device, so since we are working with 50' increments on this site, I measure 50' of string and tied it to a wire stake, we will see if this works.

I didn't end up doing this, but one thought I had was if we wanted to include fixer in this kit, each bag of fixer makes 1 gallon, so we can divide it into 4 equal parts and use a 1 quart plastic bottle, put the dry fixer in, and then the person collecting the experiment can fill bottle with water, and possible use the same bottle to put the strips into, then just dump out the fixer, fill with water, rise and leave the cap off so it dries, and just mail the bottle back.



hydrogen-sulfide-sensing hydrogen-sulfide h2s h2s-photopaper

1 Comments

Great kit assembly instructions!


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