Scubajoe1
New member
So I spoke to the folks at Hanna today and asked...
Hi there, I am a chemist and an avid marine aquarium enthusiast. I was curious as to why Hanna has not come out with a nitrate marine test kit. I have made a standard curve in my lab for nitrates at 0,1,2,3,4,5 and 10 ppm. From this curve I am able to elucidate the nitrate concentration for my reef aquarium by running the sample through a UV spectrometer and getting an absorbance reading. It seems the chemistry is already established for the reaction and there is a HUGE market value for a digital test kit for nitrate. I use the Hanna checkers for all my other assays and was wondering why the nitrate test kit has not been introduced. Can you please forward this to your R&D department for a possible explanation and suggestion.
They quickly replied with...
Thank you for your input regarding a Nitrate Checker HC. It would not be a stretch for us to offer a Checker HC for Nitrate testing since we currently offer the HI96728 portable version. All of the Hanna Checkers are based on previous versions of our portable colorimeter line. The current portables use a tungsten lamp with a narrow band interference filter that excluded all other wavelengths except the one of interest. The previous versions used an LED at a specific wavelength as a light source. The majority of the Checker HC's are using an LED as a light source.
The portable meter for nitrate is using 525 nm which we have an LED for, so from a mechanical standpoint there are no issues. From a chemistry standpoint the cadmium reduction method has two issues:
There is a chloride interference above 100 mg/L. This would seem to be overcome if the curve is developed with standards prepared in artificial seawater.
The method is very sensitive to how the sample is mixed. This is a bit of challenge. In order to get consistent results an SOP would have to be developed in which the mixing procedure can be standardized and repeatable. It might have to include the use of a magnetic stirrer.
The above are what I believe to be the reasons that we have not moved forward with a Nitrate Checker. I will have to confirm with the R&D Department.
Out of curiosity, are you using a chemical method when doing the absorbance measurement in the UV range? I know that in process measurements of nitrate at a wastewater plant a UV based sensor (210 nm) is used in situ. There is no chemistry so I want to make sure that this is the technology that you are referring to. If it is not and you are using a chemical method then any information about the method would be useful.
Lastly, As we have the alkalinity Checker for saltwater aquariums, I am curious if we should offer a unit that displays in dKH as opposed to calcium carbonate. It seems that in the forums dKH is more common. Since it is only a change in programming it would be relatively easy to do as well.
If I find out more information then I will forward on to you as well.
Sincerely,
Paul Fabsits
VP of Product Marketing
Hanna Instruments
Hello Paul,
Thanks for getting back to me so quickly. I think the hanna alkalinity checker is fine"¦.similar to the phosphorus one we just have to multiply or divide by a constant. Ideally the phosphorus checker should measure phosphate instead of phosphorus because that's what we are interested in but like I said not a deal breaker.
In regards to the nitrate test I currently use the chemistry in the red sea test kit and do make the standards in salt water. I then tested a standard I made against the standard curve and come out pretty close. I did not need a stir bar"¦.I mix 5 drops and shake for 15 seconds, add one scup of reagent two and shake for a minute and then one scoop of reagent three and shake for 15 seconds. Then you wait 9 minutes and read. I did find that I had to filter the sample through a 0.22 or 0.4 micron filter to obtain the best reprducible results.
I would also maybe make a high range and a more accurate low range meter as well.
Hope this information helps.
Joe
So we will see what comes next
Hi there, I am a chemist and an avid marine aquarium enthusiast. I was curious as to why Hanna has not come out with a nitrate marine test kit. I have made a standard curve in my lab for nitrates at 0,1,2,3,4,5 and 10 ppm. From this curve I am able to elucidate the nitrate concentration for my reef aquarium by running the sample through a UV spectrometer and getting an absorbance reading. It seems the chemistry is already established for the reaction and there is a HUGE market value for a digital test kit for nitrate. I use the Hanna checkers for all my other assays and was wondering why the nitrate test kit has not been introduced. Can you please forward this to your R&D department for a possible explanation and suggestion.
They quickly replied with...
Thank you for your input regarding a Nitrate Checker HC. It would not be a stretch for us to offer a Checker HC for Nitrate testing since we currently offer the HI96728 portable version. All of the Hanna Checkers are based on previous versions of our portable colorimeter line. The current portables use a tungsten lamp with a narrow band interference filter that excluded all other wavelengths except the one of interest. The previous versions used an LED at a specific wavelength as a light source. The majority of the Checker HC's are using an LED as a light source.
The portable meter for nitrate is using 525 nm which we have an LED for, so from a mechanical standpoint there are no issues. From a chemistry standpoint the cadmium reduction method has two issues:
There is a chloride interference above 100 mg/L. This would seem to be overcome if the curve is developed with standards prepared in artificial seawater.
The method is very sensitive to how the sample is mixed. This is a bit of challenge. In order to get consistent results an SOP would have to be developed in which the mixing procedure can be standardized and repeatable. It might have to include the use of a magnetic stirrer.
The above are what I believe to be the reasons that we have not moved forward with a Nitrate Checker. I will have to confirm with the R&D Department.
Out of curiosity, are you using a chemical method when doing the absorbance measurement in the UV range? I know that in process measurements of nitrate at a wastewater plant a UV based sensor (210 nm) is used in situ. There is no chemistry so I want to make sure that this is the technology that you are referring to. If it is not and you are using a chemical method then any information about the method would be useful.
Lastly, As we have the alkalinity Checker for saltwater aquariums, I am curious if we should offer a unit that displays in dKH as opposed to calcium carbonate. It seems that in the forums dKH is more common. Since it is only a change in programming it would be relatively easy to do as well.
If I find out more information then I will forward on to you as well.
Sincerely,
Paul Fabsits
VP of Product Marketing
Hanna Instruments
Hello Paul,
Thanks for getting back to me so quickly. I think the hanna alkalinity checker is fine"¦.similar to the phosphorus one we just have to multiply or divide by a constant. Ideally the phosphorus checker should measure phosphate instead of phosphorus because that's what we are interested in but like I said not a deal breaker.
In regards to the nitrate test I currently use the chemistry in the red sea test kit and do make the standards in salt water. I then tested a standard I made against the standard curve and come out pretty close. I did not need a stir bar"¦.I mix 5 drops and shake for 15 seconds, add one scup of reagent two and shake for a minute and then one scoop of reagent three and shake for 15 seconds. Then you wait 9 minutes and read. I did find that I had to filter the sample through a 0.22 or 0.4 micron filter to obtain the best reprducible results.
I would also maybe make a high range and a more accurate low range meter as well.
Hope this information helps.
Joe
So we will see what comes next
