pleasantpool said:
My other question is can someone list what each of the R-#### reagants actually are chemically? I am a chemist and I'd prefer to know what I'm handling rather than some trade name.
Bill,
I can tell you the standard components of the tests since they are mostly standardized tests so there is no secret in that. There are additional chemicals added for stability and other purposes and those will be proprietary. I suggest you look at the Hach paper
"Current Technology of Chlorine Analysis for Water and Wastewater" for some useful information regarding the chlorine tests.
R-0004/R-0014
Phenol red pH indicator dye (different concentrations for sample size); also contains a mix of proprietary chlorine neutralizers (not thiosfulfate)
R-0600
Orthotolidine (OTO), chlorine indicator dye (TF-100 only, not K-2006)
R-0870
N, N-diethyl-p-phenylenediamine (DPD), powdered indicator dye plus phosphate buffer, EDTA and organic acid
R-0871
Ferrous ammonium sulfate (FAS), titrant reagent; usually modified for stability as with Ferrous Ethylenediammonium Sulfate (FEAS)
R-0003
Potassium iodide, DPD Reagent #3 used for combined chlorine (CC) test (or Total Chlorine test in some kits)
R-0005
Hydrochloric acid, acid demand reagent (K-2006 only, not TF-100)
R-0006
Sodium hydroxide, base demand reagent (K-2006 only, not TF-100)
R-0007
Sodium thiosulfate, chlorine neutralizer
R-0008
Bromocresol green and
Methyl red, Total Alkalinity (TA) indicator combination dye
R-0009
Sulfuric acid, for TA titration
R-0010
Sodium hydroxide, Calcium Hardness (CH) buffer (precipitates magnesium hydroxide to test only calcium hardness)
R-0011L
1-(2-Hydroxy-1-naphthylazo)-2-naphthol-4-sulfonic acid sodium salt (Calcon), Calcium Hardness (CH) indicator dye
R-0012
Ethylenediaminetetraacetic acid (EDTA), Calcium Hardness (CH) titrating reagent
R-0013
Melamine, Cyanuric Acid (CYA) reagent; usually has pH buffers to force low pH; forms melamine cyanurate in the test
R-0630
Potassium chromate indicator chemical for chloride salt test (forms red silver chromate)
R-0706
Silver nitrate titrating reagent that precipitates silver chloride
As a general rule, the indicator dyes are the least stable as they are organic dyes. The FAS reagent is also less stable and also sensitive to light. The strong acids and bases will last essentially forever while the other chemicals last somewhere in between (potassium iodide, EDTA, sodium thiosulfate) mostly dependent on their exposure to oxygen in the air.
This link from Taylor may be helpful to you in recognizing a compromised reagent.
Since you are a chemist, it would be great if as you peruse the site and run into the technical posts, especially in The Deep End, if you would correct anything you see that might be wrong or incomplete. Just ask in the appropriate thread or if it's something I've written and you don't want to post, PM me. Welcome to TFP!
