R-0011 drops

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RPSalty

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Jan 25, 2019
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Land O'Lakes, FL
Pool Size
15000
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Plaster
Chlorine
Salt Water Generator
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Hayward Aqua Rite Pro (T-15)
I cannot squeeze a drop out of the bottle. This is the second bottle with this problem. The bottle is under a year old and is stored inside the house 70-75 degree range.
I'm talking scrunching the bottle with two hands. I've cleaned the tip, no residue, and I can blow air through it. Is this normal?
 
Maybe add some distilled water to the bottle and mix.

Adjust the number of drops to account for the difference.

For example, if the resultant mixture is 75% reagent and 25% distilled water, add 10/.75 = 13 drops.
 
Soak the fitment (tip) in 90% or greater isopropyl alcohol. The fitment just pops off with a little lateral force. Be careful not to splash the indicator all over the place.

The R-0011L indicator is NOT water soluble. In fact, it’s a very difficult indicator to work with because it has poor solubility in most solvents that are convenient to work with. So the indicator compound can precipitate out of solution when it’s cold or left sitting for too long.

You can also just get a standard glass or plastic eye dropper and suck up the indicator that way to add a drop or two to your CH test. The amount of indicator added to the test is not critical as it is typically added in excess of what is needed. So even if you add a tiny bit more than what you would get from the actual bottle dropper, the results should be pretty close. The color may look a little deeper and darker if you add more than usual but the transition point will be unaffected.
 
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JoyfulNoise said:
The R-0011L indicator is NOT water soluble. In fact, it’s a very difficult indicator to work with because it has poor solubility in most solvents that are convenient to work with. So the indicator compound can precipitate out of solution when it’s cold or left sitting for too long.
Click to expand...
If the solvent is isopropyl alcohol, couldn't you add some to thin it out?

Maybe poke the hole with a pin to make it a little bit larger.
 
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JoyfulNoise said:
The R-0011L indicator is NOT water soluble.
Click to expand...
What part is not soluble in water?

Calmagite and Eriochrome Black are soluble in water.

JoyfulNoise said:
The Eriochrome Black dye used in the test "grabs" the Ca2+ ion from the water, this is what causes the dye to change from blue (it's normal color in water with no calcium) into reddish-purple.
Click to expand...

Eriochrome Black T is soluble in water.

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www.fishersci.com

Eriochrome Black T, ACS Grade, LabChem - Biochemical Reagents, Staining Reagents

www.fishersci.com www.fishersci.com
 
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JoyfulNoise said:
The reason being is that the R-0011L dye is a chelating agent and it captures calcium ions to make the color go from blue to red. If you have too high concentration of calcium ions, you may not have enough dye in the test to fully chelate all the calcium. As well, if the dye concentration is too high, that can cause problems too. Complexometric titrations are very tricky to do right because it's not based on a pH change but a very sensitive competitive reaction between different strength chelation compounds (EDTA/CDTA versus Eriochrome Black) so, if you don't follow the protocol exactly or you are outside the intended ranges, results can vary.
Click to expand...
 
The indicator eriochrome black T (EBT) is used to signal the presence of ions in the water sample.

EBT binds with free metal ions in the water to form a pink complex.

EDTA has a stronger affinity for the metal ions than EBT so when EDTA is added it replaces the EBT and the EBT returns to its blue, uncomplexed color.

The blue color is used as the end point in the titration.
_____________________________________________________________________
Eriochrome Black T (EBT) indicator is added to the sample, and EDTA (ethylenediamine tetraacetate) is titrated into the sample.

EBT has a red color in the presence of free calcium and magnesium ions.

As EDTA is added to the sample it complexes (sequesters) the ions.

In the absence of free calcium and magnesium the EBT will turn blue indicating the endpoint of titration.
________________________________________________________________________
Hardness in water can be determined quickly by titration and the use of color indicators.

By proper choice of pH, total hardness (Ca2+ and Mg2+) or the portion contributed by calcium and magnesium individually can be measured.

The traditional test for hardness involves pH adjustment to 10.1 with an ammonium buffer, addition of Eriochrome Black T indicator [1-(1-hydroxy-2-naphthylazo)-6-nitro-2-naphthol-4-sulfonic acid] and then titration with Na2EDTA (ethylenediaminetetraacetic acid, disodium salt) solution.

Some other indicators are more stable, giving a faster reaction and a more distinct end point than Eriochrome Black T.

One of the best is calmagite, 1-(1-hydroxyl-4-methyl-2-phenylazo)-2-naphthol-4 sulfonic acid, which is used in Hach total hardness tests.
 
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You could probably use distilled water, Triethanolamine or isopropyl alcohol or maybe all three to thin out the reagent.

Probably worth a try since most people have distilled water and isopropyl alcohol.

Triethanolamine is available if you wanted to get some, but probably not worthwhile.
 
Sorry, I was thinking of a different indicator. The ECB itself is soluble in water but the stabilizers used - di- and tri-ethanolamine - tend to leave residues in the tip when left standing. Diethanolamine is more of a viscous substance that absorbs water and increase viscosity. Triethanolamine behaves similarly. Because of the shape of the tip, the liquid indicator gets left behind as a film and dries. This tends to form hard clumps that don’t dissolve well in water but dissolve a little easier in alcohols.

I have found soaking in IPA works but you can also just use a fine metal wire like a thin paper clip or a wooden tooth pick and poke the tip of the fitment. It should dislodge any clump.

Another issue is that the indicator just degrades with age and forms clumps in solution. These clumps will naturally block up the tip when you squeeze the indicator bottle. They don’t redissolve on their own and Taylor says to get rid of the indicator when it forms clumps. It’s just a finicky reagent to work with. I’ve thrown out more full bottles of R-011L than I’ve ever used. It sucks but that’s why these types of reagents are often mixed up in testing lab when needed rather than trying to store the solutions.
 
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