1. Water Analysis Protocol
Marine Chemistry
Lab Practical

2. Parameters to Measure... Water Sampling Collection pH
Temperature & Salinity
Dissolved Oxygen (D.O.)
Carbon Dioxide (CO2)
Nitrates (NO3-)
Plankton
Turbidity
Phosphates (PO4-3)

3. Water Sampling & Analysis
RULE OF THREE
Rinse container and discard with sample water twice
Keep the third sample

4. Dissolved Oxygen Test Winkler Titration Method
Two Parts
1. Fixation Procedure (“Pickling”)
2. Titration

5. Fixation Procedure (“Pickling”)
1. Add 2 mL of manganeese sulfate (MnSO4) about 1 cm below the surface of the water. Mix and let precipitate settle.
2. Add 2 mL of alkaline iodide (NaI) reagent about 1 cm below the surface of the water. Re-stopper BOD bottle and rock back and forth to mix thoroughly and let precipitate settle.

6. Fixation cont.
3. Add 2 mL of concentrated sulfuric acid (H2SO4) allowing acid to run down the inside of the neck of bottle. Re-stopper and rock back and forth to mix. Precipitate will disappear and an orangish-brown solution will remain.

7. Dissolved Oxygen (O2) “Pickling” Summary
Add 2 mL of manganesse solution
Add 2 mL of iodine solution
Add 2 mL of conc. Sulfuric acid

8. Dissolved Oxygen (O2) Titration setup
Buret with Phenylarsine Oxide (PAO) solution
Add 201 ml of “pickled “ sample in 250 mL flask
Add magnetic “bean”

9. Titration Procedure Record initial PAO level
Turn on magnetic stirrer and slowly titrate sample with PAO solution.
Titrate until solution turns a pale straw color.
Add a dropper (2mL) of starch solution.

10. O2Titration Procedure (cont.)
Titrate drop by drop until the blue indicator first disappears (end point).
Record the final level of PAO solution.
The amount of dissolved oxygen is equal to the amount of PAO used and measured in mg/L or ppm.

11. Determining the % Oxygen Saturation
Locate your temperature and salinity values on the nomogram
Use a straight edge to connect the two values
Record the O2 solubility to the nearest tenth
Find the quotient of D.O./O2 solubility
Multiply by 100 to put into %

12. Carbon Dioxide (CO2)

13. Carbon Dioxide (CO2) Methods
1. Fill titration bottle with 20 mL of water sample
2. Add 2 drops of Phenolthalein. If sample turns red, no free CO2 is present. If colorless, go to step 3.
3. Fill Direct Reading Titrator with CO2 Reagent. Insert Titrator in hole of titration tube cap.

14. Carbon Dioxide Methods (cont)
4. While gently swirling, add reagent drop by drop until a faint pink color develops (must persist at least 30 seconds)
5. Read where plunger tip meets Titrator scale. Record as ppm.

15. Plankton

16. Plankton “Pickling”
1. Draw 3 mL of sample water into graduated test tube using pipette
2. Add 2 drops of iodine solution
3. Let stand overnight or centrifuge for 3:00 minutes.

17. Plankton Analysis
1. Pipette off the top 2 mL of pickled sample and discard
2. Place one drop of sample onto depression slide and examine
3. Examine drop by drop to completion

18. Plankton Analysis: The Microscope

20. Microscope Care Always carry with 2 hands
Only use lens paper for cleaning
Do not force knobs
Always store covered
Keep objects clear of desk and cords

21. Microscope Use Begin with stage up on low power objective
Use course adjust for initial focus
Adjust diaphragm
Use fine adjust for final focus
Change to higher objective and focus with fine adjust

22. Plankton
Labeled drawings of each organism (determine type if possible)
Total magnification
Diaphragm setting
Plankton Shape
Occurrence (count # of times seen)

23. Plankton Shapes Circles Rectangles/boxes Spirals
Chains (circle or box)
Spheres (maybe it’s spears!)
Animal
Other

24. Nitrate (NO3-) Test Methods
1. Fill tube to 2.5 mL mark with sample.
2. Add 2.5 mL of Mixed Acid Reagent, cap and mix. Wait two minutes.
3. Add 0.1 grams (1 level spoonful) of Nitrate Reducing Reagent. Cap and invert times in a minute. Wait ten minutes.

25. Nitrate Test Methods (cont.)
4. Use Octa-Slide Viewer and match sample color to color standard.

26. Phosphates

27. Phosphates (PO4-3) – Solution Prep
Fill sample cell with 10 mL of sample
Add the contents of one PhosVer 3 phosphate Powder Pillow to the cell. Stopper and shake vigorously for 30 seconds.
Start the instrument timer and let sample react for 2 minutes
Meanwhile, prepare the blank by filling a 2nd sample cell with 10 mL of sample.

28. Phosphate Test
When the timer expires, wipe the blank with a Kimex and insert into the cell holder
ZERO the instrument (0.00 mg/L PO43- will show)
Wipe the prepared sample and insert
Read the results in mg/L PO43- (or ppm)