SEAL: OWC-LE-Root_Exclusion Experiment: Apr-May2024

[zoeread]

Hi! I have a few questions about the SEAL data from the OWC-LE-Root_Exclusion Experiment, as I adjust our SEAL code to match the data, starting with Apr-May2024.

• Does this SEAL analyze for Sulfate, Nitrate, Nitrite, Ammonium, and Phosphate?
• Are Standards 0, 1, and 90-99 used for all analytes? Would you have a list of what the concentrations are supposed to be for each of the standards for each analyte (Sulfate, Nitrate, Nitrite, Ammonium, Phosphate)? Is standard "1ppb NO2-N" the same as Standard 90 for Nitrite?
• Is the CCV used as a check standard for all analytes, and what is the expected CCV concentration for each analyte?
• Would you know the lower detection limit for each analyte for this SEAL?
• Was CCB used as the blank for all analytes?
• Were there any duplicates, spikes, matrix effect, or third-party pe checks done on the samples?

[robertapeixoto]

Hi Zoe, aswers below:

• Does this SEAL analyze for Sulfate, Nitrate, Nitrite, Ammonium, and Phosphate?

correct

• Are Standards 0, 1, and 90-99 used for all analytes? Would you have a list of what the concentrations are supposed to be for each of the standards for each analyte (Sulfate, Nitrate, Nitrite, Ammonium, Phosphate)? Is standard "1ppb NO2-N" the same as Standard 90 for Nitrite?

No, we use one standard for each analyte. We can track the link between the standard and the analyte based on the “test” column. You can see the target concentration for each standard in the PDF files attached in this folder, along with details on the calibration curve.

• Is the CCV used as a check standard for all analytes, and what is the expected CCV concentration for each analyte?

The CCV is used as a check standard every 20 samples. We set 10% variability as acceptable, with values expected to be either the average between the CCB (blank) and the top standard for each variable, or half of the top standard.

• Would you know the lower detection limit for each analyte for this SEAL?

I’m not sure , I’ll get this information for you.

• Was CCB used as the blank for all analytes?

yes, it is DI water

• Were there any duplicates, spikes, matrix effect, or third-party pe checks done on the samples?

I’m collecting information from our previous lab technician on that, and if there were, I’ll paste it here next week.

=)

[zoeread]

Okay, thank you! I edited the SEAL code we use to process this data, and generated a PDF output of the QAQC.
There were some issues, which might be because I coded this wrong or because I have the wrong values for something.

• I still need the detection limit for all analytes for this SEAL to flag samples if they are too low.
• All of the check standards (CCV) were too low, except for the last check std for Phosphate, which was very high.
• For the NOx Reduction Efficiency check, it looks like the expected concentration is 1 ppm? (Lines 674+)
• It would be good if someone could check my unit conversion to uM for each of the analytes. (Lines 1134+)
  I made it so that the code pulls in the metadata as well, from "COMPASS_OWC_Root_Exclusion_Nutrient_SampleLog.csv".