Taylor R-0003 reagent #3 turned blue in the bottle

[rdshackleford]

Today I noticed my R-0003 reagent #3 turned blue in the bottle. I have the K-2006 kit. Last time I used this reagent, about a week ago, it was perfectly clear. I searched and only found that it goes bad by turning yellow. I left my kit outside last week as the temps were in the 60s during the day and the 40s at night.

Any ideas why this happened, and is the reagent useless now?

Thanks,
-R

 

[JamesW]

The only thing I can think of is starch contamination, which can react with iodine to create a blue/black color. Never seen R-0003 go blue. In any case, I would replace it.

 

[JoyfulNoise]

The reagent R-0003 is basically potassium iodide. It is possible for the KI to react with CO2 and O2 to form potassium carbonate and I2 (iodine). Solutions of KI/I2 tend to appear yellowish colored though. Perhaps some other contaminant has found its way in to the bottle and formed a blue-ish colored iodine compound.

At this point it seems like the reagent was compromised from being outside. Low temperatures (40F) are just as bad as high temps as low temps can sometimes cause precipitation of salts from solution. You should keep your kit indoors.


Sent from my iPhone using Tapatalk

 

[rdshackleford]

JN, sound reasonable. I usually keep my kit inside, but the weather was getting colder (trending from 80's to 40's in a couple of weeks), and I was testing every day and I got lazy. Yes, indeed I should keep my kit indoors. My bad.

-R