Re: [plots-waterquality] Help with Shimadzu UV1200 protocols

[Liz Barry]

Hi Max, 

What a find! I'm copying the spectroscopy list. 

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On Tue, May 31, 2016 at 9:31 PM, <maxml...@gmail.com> wrote:

Hello,

I've discovered a garage full of old Shimadzu UV1200 spectrometers and I'm wondering whether they might be useful for my water quality monitoring project. Does anyone know some Nitrate protocols for this old beast that doesn't involve Cd reduction columns?
Thanks in advance,
Max

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[Mathew Lippincott]

Real cool, Max.

Nitrogen reductase enzymes can now be used in place of Cd in colorimetric nitrate testing and are nearing approval as an official EPA method replacing Cd:

http://nitrate.com/store/index.php/nitrate/reagent-grade-enzyme-packs

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[Yagiz Sutcu]

They also have a real working spectrophotometer as well... Only $65... And open source...

http://nitrate.com/nitrate-phosphate-handheld-photometer

And a paper about it: http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0134989

[Nathan McCorkle]

On Wed, Jun 1, 2016 at 3:50 PM, Yagiz Sutcu <ygz...@gmail.com> wrote:
> They also have a real working spectrophotometer as well... Only $65... And
> open source...
>
> http://nitrate.com/nitrate-phosphate-handheld-photometer
>
> And a paper about it:
> http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0134989
>

Where do you see $65??

I see 'as low as $270'
http://nitrate.com/store/index.php/nitrate/on-site-test-kits/handheld-photometer-introductory-package

[Yagiz Sutcu]

It's the price with the emzymes...device cost is $65...it's in the paper...

[David haffner sr]

Hey Max, yeah man, here is a standard protocol for a nitrate stock solution and a standard nitrate solution for water quality testing:

• Stock Nitrate Solution: Dry KNO3 (potassium nitrate) in an oven for 24 hours at 105° C. Then dissolve 3.62 g of KNO3 in distilled water. Dilute to 500 mL in your 500 mL graduated cylinder using distilled water. Carefully swirl the solution to mix (do not shake). Store in a 500 ml bottle or jar. Label with masking tape (include date). This makes a 7200 mg/L KNO3 (or a 1000 mg/L nitrate nitrogen) solution. Note: To calculate nitrate nitrogen (NO3 -2 -N), take into account the molecular composition of KNO3 (the ratio of the molecular weight of N to KNO3 is 0.138): 7200 mg/L KNO3 x 0.138 @ 1000 mg/L nitrate nitrogen (N03-N).

 • Standard Nitrate Solution: Measure 50 mL of the stock nitrate solution using the 100 mL graduated cylinder. Pour into the 500 mL graduated cylinder and dilute to 500 mL with distilled water. Carefully swirl the solution to mix. The result is a 100 mg/L nitrate nitrogen standard. Store in a 500 ml bottle or jar. Label with masking tape (include date). • Make a new stock nitrate solution each time a calibration is conducted if the stock solution has not been preserved. Standard nitrate solutions should be made fresh each time regardless of whether the stock solution has been preserved or not. The stock nitrate solution can be preserved and stabilized for up to six months using chloroform (CHCl3) if you have safe access to this chemical. To preserve a stock nitrate standard add 1 mL of CHCl3 to 500 mL of stock solution. 

Hope this helps Dave H

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[Nathan McCorkle]

On Thu, Jun 2, 2016 at 1:26 AM, Yagiz Sutcu <ygz...@gmail.com> wrote:
> It's the price with the emzymes...device cost is $65...it's in the paper...

I still don't see $65 anywhere on their product store... the lowest I
see is "1 x Handheld Photometer +$200.00"
:(
I guess maybe their parts cost is $65, but not their selling price.

[Yagiz Sutcu]

http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0134989

[Nathan McCorkle]

On Thu, Jun 2, 2016 at 11:31 AM, Yagiz Sutcu <ygz...@gmail.com> wrote:
> http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0134989
Yes but:
"""
Currently, PLA can be purchased for $24.95 per kg [39] and NinjaFlex
TPE [44] can be purchased for $64.99 per 0.75kg meaning the total
material cost for the case of the photometer is just $4.45 [40].
Couple this cost for the case with the low cost of internals $59.14
mostly available at Digikey [45] and the total proposed cost, $63.59,
for the open-source photometer is 14.32% of current retail options
[46].
"""

So they are not selling at-cost, they are making some profit (makes sense).

[Yagiz Sutcu]

of course... but open source...files are there... if you want, you can build your own... otherwise, you can buy assembled with enzymes... for nitrate analysis, without enzymes, there is nothing much you can do...

But looks like you can modify the internal configuration and do some other type of analysis as well...

[Nathan McCorkle]

On Thu, Jun 2, 2016 at 11:50 AM, Yagiz Sutcu <ygz...@gmail.com> wrote:
> of course... but open source...files are there... if you want, you can build
> your own... otherwise, you can buy assembled with enzymes... for nitrate
> analysis, without enzymes, there is nothing much you can do...
>
> But looks like you can modify the internal configuration and do some other
> type of analysis as well...

Actually I was just registering on PLOS to comment that they didn't
actually release their electronics schematics and layout files (they
only have screenshot of schematics)... though they state:
"""
Data Availability: We have made all the data available in the paper
and S1 Appendix including open hardware design CAD scripts and
electronic layouts. In addition the source code for the software can
be found here:https://github.com/NitrateEliminationCo/NECiOpenWater.
"""

Sad day when "peer-reviewed" doesn't include people who catch simple
things like this :(

[Jeffrey Warren]

It's a nice simple design though - it probably uses two input LEDs, so only data at those two wavelength, 360 nm & 540 nm? Possibly the most expensive part is the bluetooth radio. 

[Brian Degger]

I wonder why they are using 2 leds and 2 detectors per channel?
Also I don't seem to see the microcontroller code on in the instructions.
As Nathan mentioned there is no pcb files. Definitely not a gold standard open plan.
As for selling it for $200, that sounds right if the materials cost $70 odd.
(If you want to know why,  this from https://youtu.be/UwrkfHadeQQ e explains the economics of selling hardware).

Cheers,
Brian

[Jeffrey Warren]

Hi all -- I managed to dig up the plans for that photometer on Thingiverse: http://www.thingiverse.com/thing:958405/

Plus more schematics, instructions, etc: http://www.appropedia.org/Open-Source_Photometric_System_for_Enzymatic_Nitrate_Quantification

Cool! Poorly linked I guess, but good to know it's really open source (GPL).