Triton unable to read Iodine

[SeeFu]

Got my latest Triton ICP test results. one of the messages it showed was my phosphorus and phosphate was to high so my iodine reading is unreliable. My phosphorus was 31.00 ug/l and phosphate is 0.095 mg/l. This resulted in an Iodine reading of 235.00 ug/l. I've had much higher phosphorus and phosphate readings in the pas and Triton was able to give me a Iodine reading. I dont get why my phosphorua dn phosphate reading is lower this time but they're telling me Iodine is unreliable.

I sent Triton a mesage and all they tell me to do is lower my phosphorus and phosphate.

 

[Randy Holmes-Farley]

The two chemicals do tend to interfere, and perhaps you had higher iodine in the past and it was clearer against the P background. In any case I do not know details of what they do to try to sort out these issues.

You might try an icp-ms service like Oceamo if you want such readings.

 

[Christoph]

Yes, iodine is not very sensitive in ICP-OES, and its signal is further interfered with by a phosphorus emission line. In our case, we do not report iodine readings from ICP-OES if phosphorus levels exceed approximately 150 µg/L ( about 0.46 mg/L of phosphate). At 31 µg/L of phosphorus, iodine measurement poses no issues, provided the spectrometer has good resolution.

In contrast, ICP-MS does not experience this interference and is generally the superior method for measuring iodine in water samples.

BR,
Christoph

 

[SeeFu]

so why would i have been able to get a result w/ high phosphate levels in the past but not this time? I'm just trying to figure out if I should switch to a different ICP test company or if this will be a one off event.

 

[Randy Holmes-Farley]

so why would i have been able to get a result w/ high phosphate levels in the past but not this time? I'm just trying to figure out if I should switch to a different ICP test company or if this will be a one off event.

I cannot answer that, but switching to icp ms seems reasonable if this seems to be a concern.