Dear Benjamin,

We have a Tekmar/Dorhman Phoenix 8000 UV persulfate total organic carbon analyzer that we use for dissolved organic carbon. Phenomenal instrument that has lasted nearly 20 years. We will be replacing it with the Telydyne Tekmar Fusion UV persulfate analyzer soon. Last I checked, the replacement cost was around $30K, but that was a couple of years ago.

http://www.teledynetekmar.com/products/total-organic-carbon-(toc)/fusion-uv-perslfate

For total dissolved nitrogen, we use a O.I. Analytical Alpkem Flow Solution IV autoanalyzer. This instrument is about 20 years old and is going strong. Replacement with an OI Analytical FS3700 would be about $35K and up depending on what cartridges you choose to purchase. This can do both TDN, TKN, and nitrate (and alot more) but each requires a different cartridge. The instrument does do UV persulfate digestion for TDN.

https://www.oico.com/fs3700

For inorganic nitrogen, we use a Thermoscientific Dionex ICS-1100 - it will measure nitrate and nitrite. This will be around $30K. They make a number of IC combinations, but the integrated systems are least expensive. The Aquion is probably the best bet for routine water analyses.

https://www.thermofisher.com/us/en/home/industrial/chromatography/ion-chromatography-ic/ion-chromatography-systems.html

We use a Turner A10 Fluorometer to measure ammonium and it was around $10K when we bought it. The 10AU looks to be the same instrument.

http://www.turnerdesigns.com/products/laboratory-fluorometer/10au-laboratory-fluorometer

Horiba makes some nice instruments as well, but I've never used them. Since I have only undergraduate research students, my criteria is that the instruments be robust, easy to use, and the software be reasonably understandable (a growing problem). I also have a lab tech that helps a lot.

I'm not aware of any instrument that does both carbon and nitrogen because they are measured using different methods. DOC is analyzed using NDIR and requires that the pH be lowered to 2 so CO2 can be purged (done using phosphoric acid). Theoretically, you can measure DIC this way too, but we've never tried it. Nitrogen species are measured using conductivity (IC), colorimetry (autoanalyzer), or fluorescence (ammonium). I'm not aware that any instrument that combines multiple methods for liquid samples. LECO does make a C/N analyzer for solids though, and it will do organic liquids. I doubt it would do water very well.

So, bottom line is you are looking at $110K+ to set up a full analysis of dissolved inorganic and organic carbon and nitrogen, depending on what you want to do.

Sincerely,

Brannon

Dear Ben

So far as I know the methods based on thermal oxydation followed by chemiluminescence detection are more accurate. Some analyzers proposed chemical/UV oxidation, that are less expensive but depending on your material, limitations in oxidizing it might occur.

According to my experience required volumes are not a a big issue (less than 10 ml are sufficient for replicates)

Regards

Ophelie

https://www.elementar.de/en/products/toc-water-analysis/vario-toc-select.html

vario TOC select - TOC/TNb analysis without limitations

Hi Issam Moussa. I know this is a pretty old thread but I was wondering if you could give me an idea of the cost of this apparatus ?

according to elementar France this system is worth more than 50 thousand euros