Benchmark TD-550 - Page 20

fastHEX™ Analysis Method TD-550/560 Oil in Water Analyzer
20 TD-550/560 Oil in Water Analyzer
Operation Manual
PN 106737
REV H
NOTE: If you are using lighter than water extraction solvent then refer to Section 4.2 of this manual
for lighter than water extraction solvent analysis procedure.
NOTE: The following procedure describes a 10:1 water to oil extraction ratio. If a different extraction
ratio is used, the volumes of water sample and/or extraction solvent will be different.
To analyze a sample using a heavier than water extraction solvent
1. Collect 100 mL of produced water in a clean, graduated prescription bottle.
2. Add 6 N hydrochloric acid until the pH of the water sample is < 2. Check the pH with pH paper.
NOTE: Depending on the method philosophy of the facility, the sample can be measured at normal
pH.
3. Add 10 mL of extraction solvent and securely cap the prescription bottle with a clean, Teon-
lined septum cap.
4. Extract oil from the water by vigorously shaking the prescription bottle for 2 minutes.
5. Allow the extraction solvent to separate from the water for approximately 1 minute. If the
extraction solvent is trapped in an emulsion; break the emulsion by agitating with a clean
pipette. Allow the extract to sit for several minutes after agitating the emulsion. This will allow
the solvent to separate from the water. The solvent extract will be on the bottom of the bottle,
underneath the water.
6. Place a blunt needle on the end of a 3 mL plastic syringe. Push the syringe plunger all the way
in.
7. Turn the prescription bottle upside down and allow the solvent extract to settle on top of the
Teon-lined septum cap.
8. While holding the prescription bottle upside down, insert the needle through the Teon-lined
septum cap far enough for the end of the needle to be in the solvent extract.
9. By pulling the syringe plunger out, withdraw 1-1.5 mL of solvent extract.
10. Inject the solvent extract into the cuvette (8 mm or 10 mm cuvette, the same type used for
calibration) until the cuvette is ¾ full.
11. Wipe the outside of the cuvette with a clean tissue or cloth to remove any liquid, dirt or oil that
might be present.
12. Open the sample well lid, insert the cuvette into the cuvette adapter, and close the lid.
13. Turn on the analyzer tablet and tap Start on the Start screen.