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title: "TA titrator protocol"
output: html_notebook
---
I met with Micah Horwith at DNR in Olympia regarding usage of his auto-titrator for running TA samples. This is likely to start after Dec 27, as Micah is unavailable until then. Below is a rough protoocl outline as he uses. 


Rough Protocol (Adaptation of SOP 3a from carbonate chemistry handbook): 

1. Wake up/Turn on laptop and titrator (no password for computer)
2. Open LabX 2014 on laptop.
3. Ensure proper connection between titrator and laptop, may require restarting LabX, wiggling USB connection, voodoo.
4. Ensure acid reserve is full (Brown container located behind and to right of titrator). Fill with 0.1N HCl from acid cabinet, this is in a large bottle from Fluka, with a red label. Not the Fisher 1N stuff in the smaller blue labeled bottle 
5. Insert empty sample cup and run 2x acid purge sequence on machine to purge burette of old acid that may have changed concentration due to evap. Watch for bubbles in output tube into cup.
6. From the open bottle of CRM sample (Stored in upper shelf to the right of the titrator) place 60-100 grams of sample in sample cup (on bench to right of titrator). Record mass. Salinity and other information can be obtained from Dickson lab webpage by googling "Batch # CRM Dickson". Record in spreadsheet.
7. Run rightmost titration option on titrator, entering sample name (Follows YYYYMMDDCRM form) and mass. 2 error messages will pop up, hit ok. Sample processing takes ~ 15 minutes. 
8. Repeat CRM 2-3 times to ensure machine stability. Expected values at present for pH 3.5 are ~210 mV, TA can be gotten from Dickson lab website.
9. Export .csv file from LabX software and run R script at() to determine TA and compare to known value.
10. If machine results are acceptable, proceed with field samples in similar way, recording mass, Salinity, Temperature in spreadsheet and in titrator information.
11. After 10 field samples, re-run CRM to ensure little/no variation in machine output. 
12. At end of sample running, run a final CRM to bracket samples.
13. All HgCl waste is put in HgCl waste container in sink. Any cup containng HgCl waste is rinsed 3x with DI water, also placed in waste container. Any HCl waste can go down the drain.
14. Export samples ran as .csv and upload .csv files to github/dropbox/whatever.

Considerations:

1. What do we want to define as "ok" for CRM outputs. Micah's current protocol is +/- either 5 mmol/kg or 10 mmol/kg but we could also consider just running CRMs until we get two-three equal outputs and recording any deviation from expected as an offset for mV ranges to be applied to samples.
2. How do we want to measure salinity? Micah's lab has a benchtop refractometer with +/- 1 unit accuracy. Is this good enough?
3. Micah's acid used in the titrator does not have a supplied density function as mentioned for samples run previously. Is this ok, and for reference, what acid was used for those other samples that did have a density function (supplier/part number or whatever is available?)
4. 4.0, 7.0 and 10.0 buffer samples are not run at the beginning of the day normally. Micah reports little wandering of electrode, so he's not done this normally. Is this ok, or should we do this for this project?