Titrator SOP To-Do

[kubu4]

From @kubu4 on January 23, 2018 20:51

• [ ] Create daily startup procedural checklist (possibly Google Form?) to guide and track usage. Should include:

  1. Checking acid volume.
  2. Checking rinse volume.
  3. Powering system on.
  4. Removing probes from cup in Position 0.
  5. Drying stirrer.
  6. Burette purge.
  7. Re-using acid.
  8. Position 0 contents
  9. pH calibration

• [ ] Create daily shutdown procedural checklist (possibly Google Form?)

  1. Sample disposal.
  2. Probe storage (temp and pH probes).
  3. Powering system down.

• [x] Create pH meter calibration log file

• [x] Create pH meter calibration standard curve file (R script and/or Excel file) for equilibration point determination (pH = 3.0 & 3.5)

• [x] Verbiage for graphing pH meter calibration standard curve

• [x] Determine sample volume (weight) to use for measurements: 50mL vs. 100mL

• [ ] Automate TA calculations (along with QC checks against standards/previous values)

• [x] Decide on log/data storage locations (e.g. Google Doc, Owl, Dropbox, etc.)

Copied from original issue: RobertsLab/resources#160

[kubu4]

Checked off data storage location.

Have opted for storing in local Git repo and pushing to RobertsLab/titrator/data/ repo.

[kubu4]

Checked off pH meter calibration standard curve.

Not needed, as the values are constants (e.g. pH 3.5 = 200mV). Simple act of calibrating pH meter daily will account for any "drifting" of values.

[kubu4]

Checked off sample volume determination. Will use 50g (i.e. 50mL)

Based on data shown in this notebook entry: http://onsnetwork.org/kubu4/2018/03/06/progress-report-titrator/

[kubu4]

Checked off pH meter calibration standard curve (again).

From my previous comment

Not needed, as the values are constants (e.g. pH 3.5 = 200mV). Simple act of calibrating pH meter daily will account for any "drifting" of values.

This is/was incorrect! I misunderstood the behavior of the pH meter calibration. The standard curve is most certainly needed to figure out the corresponding voltage for a given pH!

[kubu4]

Checked off sample weight determination - decided on 50g (50mL). See this notebook entry: http://onsnetwork.org/kubu4/2018/03/06/progress-report-titrator/

[kubu4]

Checked off "Create pH meter calibration log file":

https://github.com/RobertsLab/titrator/blob/master/data/cal_data/daily_calibration_log.csv

[kubu4]

Checked off: "Verbiage for graphing pH meter calibration standard curve"

Not needed. Linear model run in this script (pH_calibration_check.R) is used to determine standard curve equation.