Repurpose Hannah copper checker?

[taricha]

So, given some time and given enough charted data, we may all be in possession of universal Hanna checkers?

So, you're saying there's a chance...

If you wanted a universal Hanna checker, you'd get a colorimeter (or spectrometer) instead of a half dozen checkers.

 

[Sean Clark]

If you wanted a universal Hanna checker, you'd get a colorimeter (or spectrometer) instead of a half dozen checkers.

I never claimed to be smrt. That is why I need to see the numberz.

 

[Dan_P]

If you wanted a universal Hanna checker, you'd get a colorimeter (or spectrometer) instead of a half dozen checkers.

The phosphate Checker is pretty close to the universal Checker. The broad visible spectrum of many test colors makes this possible, not perfect, but useful.

Let’s see, the LR PO4 Checker could cover nitrate, nitrite, phosphate, iodine, ammonia maybe. I haven’t tried Ca or alkalinity yet. In some of these tests, the concentration range might be disappointing, but as an exercise, it would be fun to show how close it does come to being a universal Checker, or at least the one you could use in a pinch.

 

[gbroadbridge]

If you wanted a universal Hanna checker, you'd get a colorimeter (or spectrometer) instead of a half dozen checkers.

Now you've got me thinking about a light source and my x-rite display colorimeter

Just joking ...

 

[Rick Mathew]

The answer is kinda, but not a good idea to use the hanna HR NO3 packets in the Cu checker. And there's a better solution available.

Here's calibration data for my tank water spiked with a few NO3 levels and run the hanna HR NO3 chemistry on it, and put it in either the hanna HR NO3 checker or the LR Copper checker.

Total ppm NO3 stock	HR NO3 checker (ppm)	LR Cu checker (ppb)
0.0	0.5	51
2.1	3.0	119
5.1	6.4	207
10.3	11.4	423
20.5	22.3	748

and while it looks good....

This is not a good wavelength for this test.

The LED wavelength for the Cu checkers is going to be out around 575nm which means you are measuring waaay on the edge ot the peak. Measuring that far out means that small differences (one LED's checker vs the next, one reagent lot vs another) will mess up the result a lot.

But, you should instead run a Red Sea NO3 test in the checker.
Red Sea NO3 color is much closer to the right wavelength for the Cu checker.

This is the spectrum of the Red Sea NO3.... measured by @Rick Mathew here

as you can see, the 575nm hits very near the fat part of the peak and is a much better pair to use.

In fact, it looks like Rick may already have done this years ago.
This is regression data for measuring Red Sea NO3 with a hanna HR copper checker. (different model Cu checker, but I'll bet it works the same.)


Rick's approximate regression is about [NO3 ppm] = 6.0 x [Cu checker ppm].

@Red2143 you may give that a try.

It is almost exactly the same within the reported error of the checkers...

 

[taricha]

This is a bit in the weeds, but I thought it was plausible and I was curious enough to check, so might as well share.

The API nitrate test likely uses chromotropic acid as its azo component which is yellow-red. API nitrite and Hanna nitrate and all other purple-pink nitrite/nitrate tests likely use N-(1-naphthyl)ethylenediamine.

Looks Like API is actually just the same zinc reduction as Red Sea etc with a lot of yellow added.

API NO3 with ~zero and ~20ppm NO3


And here's the spectrum of the Zero, the 20ppm and the difference...

The difference shows that the actual color response to NO3 is centered around ~530-550nm which looks a whole lot like the Red Sea color production spectrum below...

This is the spectrum of the Red Sea NO3.... measured by @Rick Mathew here

And not like the chromotropic acid method where the amount of yellow is the response to NO3 and that's what's measured around 410-430nm.

Back to relevance to this thread - the spectrum above makes me think API NO3 would also be a good fit for the hanna Copper checker at 575nm.

 

[Malcontent]

This is a bit in the weeds, but I thought it was plausible and I was curious enough to check, so might as well share.


Looks Like API is actually just the same zinc reduction as Red Sea etc with a lot of yellow added.

API NO3 with ~zero and ~20ppm NO3


And here's the spectrum of the Zero, the 20ppm and the difference...

The difference shows that the actual color response to NO3 is centered around ~530-550nm which looks a whole lot like the Red Sea color production spectrum below...



And not like the chromotropic acid method where the amount of yellow is the response to NO3 and that's what's measured around 410-430nm.

Back to relevance to this thread - the spectrum above makes me think API NO3 would also be a good fit for the hanna Copper checker at 575nm.

I think there are at least two chromotropic acid methods. Hanna's HR nitrate is very likely based on the Nesterenko papers but I think they changed the dye(s) because this is what the first Nesterenko paper (which used chromotropic acid) pictures:

The other chromotropic acid method absorbs at ~420 mm and Hach describes it as "nitrate, chromotropic acid finish." It is indeed just yellow that intensifies in proportion to nitrate concentration rather than a yellow-red scale.

 

[Red2143]

Wow so does that mean we just need a calibration curve to use api nitrate with the copper checker?

 

[taricha]

Wow so does that mean we just need a calibration curve to use api nitrate with the copper checker?

Yep. There's a bunch of yellow, so zero nitrate won't map to zero reading on the checker, but again - nothing a good calibration curve can't handle.

On NO3 tests like this, the shaking technique matters in weird ways. that is, even stuff like shaking it in an API glass vial vs a hanna cuvette can give a little different result.

 

[Red2143]

Yep. There's a bunch of yellow, so zero nitrate won't map to zero reading on the checker, but again - nothing a good calibration curve can't handle.

If we ask you very nicely will you make one, please?

 

[taricha]

Hanna's HR nitrate is very likely based on the Nesterenko papers but I think they changed the dye(s) because this is what the first Nesterenko paper (which used chromotropic acid) pictures:

I see what you mean....
"Abstract
A non-toxic solid-phase test reagent for rapid determination of nitrite and nitrate was developed. Powdered reagent utilised azo- and diazo-components (p-nitroaniline and chromotropic acid, respectively), solid organic acid acidifier (malonic, maleic or oxalic acid), zinc dust (for nitrate determination), catalyst and masking agent. Effects of solid acidifier and the amount of Zn reducing agent were evaluated. The optimal reagent formulation was established in terms of dynamic range and response kinetics, and validated by parallel measurements in split samples using an accredited ion-chromatographic method. The optimal reagent contained malonic acid as acidifier and 1.0% of Zn reducing agent, and showed good sensitivity for the determination of nitrite (LOQ of 0.03 mg L−1) and nitrate (LOQ of 0.17 mg L−1), and fast analysis time of under 6 min. These reagents were shown to be stable for at least 3 months with RSD of <3%."

The authors frankenstein-ed together a zinc reduction and chromotropic acid method
That description seems to fit the properties of the HR nitrate quite well (tiny zinc amount etc). Not that I'd be able to follow the proposed reactions, besides that chromotropic acid method also seems to convert NO3 to NO2 before color formation, so at least in that basic respect I imagine how it can be complementary with a zinc reduction.

 

[taricha]

If we ask you very nicely will you make one, please?

I'll look to see if my low range copper checker covers enough of the range to be useful. It goes up to 1ppm Cu instead of 5ppm like the high range.
If not, then @Rick Mathew might still have a high range Cu checker to do the job, if he's bored - maybe he'll run a quick 4 or 5 point curve.

 

[Rick Mathew]

I'll look to see if my low range copper checker covers enough of the range to be useful. It goes up to 1ppm Cu instead of 5ppm like the high range.
If not, then @Rick Mathew might still have a high range Cu checker to do the job, if he's bored - maybe he'll run a quick 4 or 5 point curve.

Taricha, let me know how it works out...be glad to help but it won't be quick...I am traveling for the next few days...Also I think my API test kit is most likely expired...will need to get another one...

 

[Rick Mathew]

I'll look to see if my low range copper checker covers enough of the range to be useful. It goes up to 1ppm Cu instead of 5ppm like the high range.
If not, then @Rick Mathew might still have a high range Cu checker to do the job, if he's bored - maybe he'll run a quick 4 or 5 point curve.

One other thought...You could always do the reaction dilute it to bring it in range of the tester then multiply the value by the dilution factor....I do this with my nitrate test when it pushes out of range of my HI-764...Should also work for a calibration curve...It adds a bit more variability but I would guess not a great deal...

 

[taricha]

One other thought...You could always do the reaction dilute it to bring it in range of the tester

Good idea. That's what I'll do for out of range samples.

 

[TangerineSpeedo]

This is amazing... I don’t understand any of it, but curious of the results...
Science rocks!

 

[Malcontent]

You know what'd be crazy? Replacing the LED with one of a different wavelength.

If I had a not-useful Checker such as the nitrate LR I'd give it a shot but the only one I have is the nitrate HR.

 

[taricha]

You know what'd be crazy? Replacing the LED with one of a different wavelength.

If I had a not-useful Checker such as the nitrate LR I'd give it a shot but the only one I have is the nitrate HR.

I actually looked into this after tearing a checker down. The LEDs are super tiny and fiddly, and while I can buy LEDs that I think will match parameters and be run by the hanna hardware, my soldering skills aren't good enough for that kind of fine-tuned work.
besides, an open-source IOrodeo colorimeter would be a million times easier to achieve the same thing with.

 

[taricha]

If we ask you very nicely will you make one, please?

Here's what I came up with. I'm making two assumptions.
1) that Lot-to-Lot variation isn't too bad.
2) that the HR Cu checker is the same as the LR Cu checker, just reads 5x darker solutions to go up to 5ppm instead of 1000ppb=1ppm.
(I'll be able to check assumption 1, but not the assumption about the two checkers, somebody else will have to test that.)

(EDIT: this won't work for different lots. Lot to lot variation is too big. see post 44 )


The curve calculation is [ppm NO3] = 7.00 [Cu checker] - 0.3

Method (same as standard API, scaled up to 8mL volume):
8.0mL sample water in hanna cuvette
16 drops reagent 1
cap on, invert cuvette 10x
(follow API directions about aggressively shaking reagent bottle 2)
16 drop reagent 2
cap on, shake cuvette hard for 1:00 minute
wait 5:00 minutes (6:00 min total from start of the shake)

make the yellow blank (can be done before or during the 5:00 minute wait)
add 8.5mL sample water to another hanna cuvette
16 drops of reagent 1
cap on invert 10x
(no reagent 2)

Use the yellow blank as C1 in the Cu checker, and the reacted sample as C2.
the yellow blank is how you get zero NO3 to read as zero on the checker, and probably lower a little of the lot-to-lot variation.

 

[Rick Mathew]

I actually looked into this after tearing a checker down. The LEDs are super tiny and fiddly, and while I can buy LEDs that I think will match parameters and be run by the hanna hardware, my soldering skills aren't good enough for that kind of fine-tuned work.
besides, an open-source IOrodeo colorimeter would be a million times easier to achieve the same thing with.

Here is some links to what @taricha is talking about. In the one video they are actually measuring Nitrate and Ammonia

Open Colorimeter

The Open Colorimeter is a portable and customizable colorimeter for measuring absorbance, transmittance and concentration. The cuvette holder and enclosure are made from 3D-printed black nylon material and the electronics are programmed with open source firmware written in CircuitPython.

iorodeo.com

Getting Started: Basic Operation & Menu Navigation

These instructions below apply to all variants of the Open Colorimeter. The Open Colorimeter has the following features: * On/Off switch: An on-off switch will save battery power when not in use * Micro USB Port: You can power from the Micro USB port and it will also charge up the

blog.iorodeo.com

New video tutorials & user guides for the Open Colorimeter

New instructional videos and user guides for the Open Colorimeter. Link to subscribe to our YouTube channel.

blog.iorodeo.com