I use the taylor 2006 test kit. My dpd has turned black and hardened. I just ordered a replacement dpd. Why does thishappen? Its also stained my test tube vial with some black spots that i cant really get off.
Taylor test kit
- Thread starter moreira85
- Start date
It gets wet from the humidity I would guess.
It should still work if you crush it back up.
You should be able to clean the vial with a little diluted muriatic acid.
It should still work if you crush it back up.
You should be able to clean the vial with a little diluted muriatic acid.
This evening, I was looking at my tester cylinder that I use with my SpeedStir and noticed black residue on the bottom. I wondered what it was. Now I realize it must be from the dpd crystals that don't dissolve. They get smashed into the bottom by the magnetic stir bar and leave a stain.
Yep, the powder stains stuff blackish. The blue scooper, the tray the blue scooper sits in. My chlorine only test vial isn't stained though.
R-0870 (DPD Powder) and R-0871 (FAS-DPD Titrating Reagent) are more sensitive than most reagents and require extra care in storage. It sounds like your DPD Powder was exposed a little too long to humid conditions, which causes the black color you are seeing. This black can then get on other pieces in the kit. To prevent this from reoccurring, we recommend you avoid getting the little blue dipper spoon wet and that you make sure to recap reagents tightly after each use. Also, remember to follow good storage practices like keeping all reagents in a temperature range of 36°-85°F and keeping them out of direct sunlight.
Finally, rinse any comparator tube or sample tube thoroughly after use to avoid any discoloration from reagent residue.
Thank you for using Taylor products!
Great advice above. Keeping my R-0870 inside and closing the lid tightly really retards that darkening and clumping. Cleaning the Cylinders, spoon, and anything that can have residual R-0870 will keep all you other stuff in good shape. If the mixing cylinder darkens, I use a little muriatic and water (3:1) and it cleans up easily.
The overall takeaway is keep your testing material always clean and always indoors in a humidity and temp controlled environment. It really extends the life.
The overall takeaway is keep your testing material always clean and always indoors in a humidity and temp controlled environment. It really extends the life.
Well hey I didn't know Taylor had representation here. That's cool!
I keep my entire test kit indoors, and honestly I even do most of my tests indoors (even though I know I probably shouldn't). After about 2 months of use now, I've got black marks in the bottom of my tube. I rinse thoroughly both before and after my tests, usually with reverse osmosis filtered water. I don't think there's any way to avoid it, you'll get some marks somewhere. But I'm not worried about it at this point. If it does get bad enough I'll do as duraleigh suggests.
I keep my entire test kit indoors, and honestly I even do most of my tests indoors (even though I know I probably shouldn't). After about 2 months of use now, I've got black marks in the bottom of my tube. I rinse thoroughly both before and after my tests, usually with reverse osmosis filtered water. I don't think there's any way to avoid it, you'll get some marks somewhere. But I'm not worried about it at this point. If it does get bad enough I'll do as duraleigh suggests.
Weird. I have been using the same vial for years for the FAS-DPD and have never had dark marks appeared. There is slight discoloration, but not enough that I have felt the need to try to clean it.
Very interesting, and glad to find this thread. I just posted a new thread, "Problem with R-0870" with similar issues. I can't get the solutions to go clear during the test, and am guessing at the results. Never had this before in 4-5 years. My test kit is inside my workroom, not air conditioned, and sometimes gets into the 90's. In central California the humidity never gets above 20%. I screw the lid onto the R-0870 tight. That stuff was clumped when it arrived, fresh, a few months ago, and has gotten darker and darker. My test vial is also stained purple.
I'll ask TFT for a replacement.
I'll ask TFT for a replacement.
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