6. Calibration TTP

This is an outline plan for a trial calibration.  (TTP = tactic technique procedure)

Pack up the diy photometer – we’ll call this B for broadband photometer
Be nice to have the first generation  temperature and pH tool along … maybe next time.

  1. couple of liters of sea water
  2. supply of pyrex 1ooml  covered cylindrical sample jars with lids
  3. broad band photometer- the thing we made .  We’ll refer to this as “B” for broad band
  4. macbook for last minute programming and computation
  5. power strip and an arduino power supply
  6. in the lab
    1. narrow band spectro-photometer — we’ll refer to this as “N” for narrow band
    2. prepared purified mCP  adjusted to an RN value of 1.6 or  pH 7.82
    3. deionized H20
    4. 1 N HCL
    5. 1 N NaOH
    6. temperature measurement instrument
    7. salinity measurement instrument
  1. Prepare samples of sea-water with a range of pH for the calibration with pH from 7.6 to 8.2
  2. Measure salinity (S) and temperature T ( in ºK)
  3. obtain RN and RB readings
    1. for each sample
      1. measure blank for both N and B
      2. measure absorption for N and B
      3. calculate RN and RB
  4. take RN and RB as ordered pairs and run a linear regression to obtain the regression line equation and correlation coefficient, variance and so forth – this is the calibration.
  5. determine the fit of the calibration with Equation 8 from B.Yang et.al.

Back on the Bench

Program the RN/RB regression line calibration  into the photometer firmware Equation 8  — at this time there’s no way to user-edit  S and T used in the pH calculation – maybe upgrade software a bit to make this possible… these values do affect the pH value.

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