Iodide test - Seachem kit and Hanna Silica meter

[kecked]

Great idea. I can measure and record all the tests for color development over time so we can see how critical time is to all the tests. I can do some of that this weekend using the bw units. Nice thing is I can save full spectrum as excel data for analysis. I’m really interested in how sharp the absorbable peak is. That magenta in nitrate means green is pretty widely absorbed. If so you can use leds with no filter. Filters are expensive. Tungsten lamps are hot and burn out.

The iodine test is impossible for me to read by eye at all. Remember for nitrate we are really measuring nitrite.

I’m interested in the 200-300nm abs for nitrate I read about. That is interesting but I have only hg lamp at 195 as a source out there. Deuterium ain’t cheap.

Anyway what test kit shall I get for this?

 

[taricha]

The Seachem iodide kit is the first test kit I've run across where the color forms and then disappears in seconds while you are looking at it.
(edit: and that's the one that I'm using in this thread)

 

[taricha]

I wonder if this can be used to increase precision and effectiveness with iodine dips.

No. and maybe kinda Yes.

No: the seachem iodide kit is for iodide only, it ignores iodate entirely so far as I can tell (kit documentation makes no mention of the existence of iodate anywhere). And it detects iodine in a different mechanism entirely, so the data from this thread won't help.
from kit directions...

3. Add one full stem of sample using sample pipette to the test cavity containing Iodide Reagent 1. [If a blue color develops now, elemental
iodine is indicated. This should be viewed as a hazardous status. Use a dechlorinator such as Prime™ to remove elemental iodine.]

So if it goes blue halfway through the steps, before final reagent, then you have elemental iodine. It makes no intent to quantify that amount - only identify it as hazard to be removed.
and the final issue is that the amount of iodine that would be used for a dip is certainly orders of magnitude higher than what this method and data is set up to find.
so basically, no. no methods or data in this thread will help quantify Iodine for dipping.

But also kinda yes.
the test kit does apparently pick up color with presence of iodine (never tried it), and if the color stable for some decent number of seconds and scales with concentration, then the color can be quantified with the hanna meter, and no matter how concentrated the dip is, some scheme of dilution will get it to a testable range, and another calibration curve can be found. And as you can tell, there are some innovative resourceful folks floating around these parts.

 

[kecked]

https://oceanoptics.com/wp-content/...er-Sensor-For-Nitrate-Using-Uv-Absorption.pdf

I like this approach. Might be able to do the same for everything else. Now you have a fiber coil in your tank connected to a spec. Since you know what you want the array and grating can be very cheap. UV leds exist. Though not to 200-210nm where I want to be. 305nm works but I see a lot of interference out there. 205 is devoid of issues.

So which test kit do you want me to test? I also got a bifurcated cable coming and tung hal deu lamp coming for the reflectance testing. I will use sunshine as the source for this weekends test on the color cards. I will also see it I can determine the cymk colors to print an exact match for the solutions. I might be able to find a dye with near the same colors you look through. That would be much better than reflectance comparing. Mix in PVA to start so make chart.

 

[taricha]

@kecked my crazy brain keeps reading your posts and forgetting if I'm here in the Iodide thread or
the Nitrate thread from Rick or myself
anyway, The Seachem Iodide test being used in this thread would be helpful to analyze. For two reasons.
1) its color development is time dependent, and disappears. There's a time window when it should be looked at to get accurate results. That window depends on the concentration of Iodide in the sample. higher concentration reacts fast, gets dark and disappears fast too. concentration just above detectable reacts slower, and seems to hold color longer. In the first post I put my attempt at defining the time window for high and low concentrations. in post #20 you can see my data for high concentration time.
2) full spectrum of the color end product would be cool, to know if we use the Hanna ULR P meter at 525nm how much different the absorption we could expect to be vs the hanna LR Si meter that this data was worked out for.
Obviously what is happening in 1) could interfere with measuring spectrum in 2) if it takes too many seconds to move through the spectrum. You know your equipment better than I do.

 

[kecked]

sorry for the cross threading. I started in nitrate....

Well the unit will be here today. First up is the color measurement. I have to go get a test to measure. Also I have to scale up the reaction to get enough to fit a 10ml cuvette. I also have to fiber launch a flashlight as my source for now. Tung deuterium lamp not here yet. Standbye

 

[taricha]

sorry for the cross threading. I started in nitrate....

Well the unit will be here today. First up is the color measurement. I have to go get a test to measure. Also I have to scale up the reaction to get enough to fit a 10ml cuvette. I also have to fiber launch a flashlight as my source for now. Tung deuterium lamp not here yet. Standbye

All good. Thanks so much for the help.
The way I generated the data in this thread was to modify the seachem test to take place inside the 10ml hanna cuvette, so if we're trying to track the time dependence of color development and disappearance, then it needs to follow same protocol for it to apply to the data in this thread...

Take 10 ml of sample water in the hanna cuvette. Pour the 1 scoop of Iodide reagent 1 powder into the cuvette, shake it for like 20-30sec (it won't dissolve). This is your blank "c1" in the hanna meter.
Instead of using two drops of Iodide reagent 2, you'll drop twenty into the cuvette, because the sample is way bigger than intended.
Add drops quickly and time yourself. shake for a couple seconds it'll go blue- this is your "c2".

When I say "time yourself" - I started timer as I began adding 20 drops from the provided pipette, so after I finished 20 drops, and started shaking - it was at ~15sec on the timer.

 

[taricha]

Anyone who has the hanna alkalinity meter can help with a cheap quick check - using calibration solutions - that'll extend these results to a more common meter, read on....

This data was worked out with the Hanna Silica Low Range (hi705) that checks at 610nm wavelength.
A perhaps more common meter that uses same 610nm LED and photodetector is the Hanna SW Alkalinity (hi772 - dKH or hi755 - ppm)
If you have this alk meter, and run this hanna LR Silica reference solution through the alkalinity meter, and I run the reference solution for your hanna alkalinity meter (hi772 - here, or hi755 - here) through my Silica checker, then this will give us two known equivalent readings on each meter, for a 2-point calibration and simple conversion.

(if we really wanted to make it redundant and statistically tight, we could both calibration solutions through both meters - edit: but don't know that that would tell us any more since the reference solution for each meter is already guaranteed to read at a certain known value on that meter.)

 

[kecked]

THIS IS ABOUT NITRATE

I still don't have an iodine set yet. So I ran nitrate. The absorption peak is 538-540nm you could probably go 520-550nm its broad. Will do same for iodine once I have kit. Lucky me I have a 1ml cuvette. Didn't know I had one.

 

[MnFish1]

My opinion is yes...anything that can improve the precision and accuracy of a test to provide maximum effective dosage levels has to help....I am not sure what those levels are for the iodine dip but as long as the test works withing that range it would be helpful...Actually we do a similar thing when we dose with copper for treatment....making sure the most effective treatment levels are reached and maintained...

Good question!!

I believe an iodine dip would far exceed the levels of this test - though - there are numerous protocols for Iodine dips.

 

[TLCarrico]

Ok. As a follow-up to adapting the Red Sea Nitrate test to be read by the Hanna Phosphorus ULR checker, lets spin the random wheel of Reef testing....
Nutrient: Iodide!
Test Kit: Seachem!
Colorimeter: Hanna Silica Low Range!
yeah, I know. A nutrient no one measures checked with a colorimeter no one has.
Anyway...
Take 10 ml of sample water in the hanna cuvette. Pour the 1 scoop of Iodide reagent 1 powder into the cuvette, shake it for like 20-30sec (it won't dissolve). This is your blank "c1" in the hanna meter.
Instead of using two drops of Iodide reagent 2, you'll drop twenty into the cuvette, because the sample is way bigger than intended.
Add drops quickly and time yourself. shake for a couple seconds it'll go blue- this is your "c2". Assuming its a low amount of color (Iodide <0.02) , run the "c2" between 70 seconds and 2 minutes after you started drops.
If it's a lot of color (Iodide ~.06ppm) then run "c2" 40 to 70 seconds after you started drops. The color dissipates fast after that.
...then convert...
Iodide ppm = 0.02997*(hanna reading) + 0.00104

This will work for Iodide below 0.06ppm (50/50 chance it'll max the meter at 0.06), down to about 0.003ppm Iodide. Below that, you're within margin of error of zero.
For context, Seachem says natural sea water levels are 0.06ppm Iodide, and recommends dosing to that target.
Anyway, this would allow you to detect Iodine down to 1/20th of their recommended target value.

In theory one could use this to plot the Iodine depletion rate from 0.06ppm down to undetectable.

Regarding: "Assuming its a low amount of color (Iodide <0.02) , run the "c2" between 70 seconds and 2 minutes after you started drops. If it's a lot of color (Iodide ~.06ppm) then run "c2" 40 to 70 seconds after you started drops", shouldn't that be reversed? From my testing experience using this process, the lower the color, the quicker you should test as the light color will disappear very quickly.

 

[taricha]

Regarding: "Assuming its a low amount of color (Iodide <0.02) , run the "c2" between 70 seconds and 2 minutes after you started drops. If it's a lot of color (Iodide ~.06ppm) then run "c2" 40 to 70 seconds after you started drops", shouldn't that be reversed? From my testing experience using this process, the lower the color, the quicker you should test as the light color will disappear very quickly.

I'm confident that the way I quoted was how the timing worked when I did this.
That said, the result of when the color increases and when it fades is probably dependent on the specific recipe used. Since I scaled up the test reagents a lot (but not necessarily by the same factors) to use it in a 10mL hanna cuvette instead of the default 0.6mL testing well, my guess is that the reagent ratios shifted a bunch and so how the color fades is quite likely different as a result of that.

 

[MnFish1]

I wrote a different reply - but changed it as I thought about it. IF a person recommends a non-standardized and veterinary approved test. Thats a problem IMHO. It's too bad that the author(s) didn't post it n the research section - or ask for it to be moved. Not to mention the issues with Hanna

 

[taricha]

Just to address any potential confusion what this could be useful for and what it couldn't....
This test is only to detect iodide I-, not Iodine I2, thus is irrelevant for dips or any sort of veterinary/disease purpose. And the amounts it can detect are in the 0.003 to 0.060 ppm range which is - again, irrelevant for any sort of dip/medication or similar interest.
It's only relevant for tracking iodide (I- specifically) in tank water at values in the ballpark of natural sea water and below.