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IODP (International Ocean Discovery Program) at MARUM

Salinity

Salinity is an ephemeral property and will be analyzed offshore in a timely manner after interstitial water acquisition.

Kruess Optronic Digital Refractometer DR 6200

Salinity analysis is carried out using a KRÜSS OPTRONIC Digital Refractometer DR 6200. Before starting inspect the prism window to ensure that it is completely clean. Before each measurement clean the window with a lab tissue. During the measurement the refractometer has to be placed in a horizontal position.

  • Calibration: at least once a day, additionally after each change of the setting (e.g. moving of the instrument). Put approx. 1 ml of purified water (18 - 20°C) onto the prism and close the lid and press ZERO for 3 seconds. The calibration is completed when END is displayed.
  • Measurement: Put approx. 1 ml of sample onto the prism and close the lid and press READ / ENTER. Make sure to document the resulting value in the respective analytical documentation and enter the sample in the expedition database mDIS.
  • Automatic Temperature Compensation (ATC): should be switched on for each measurement. If ATC is not displayed, press FUNC- Y/N, select menu 2, press scale to switch the temperature compensation on and confirm with READ / ENTER.
  • Temperature Unit: select from the function-menu (FUNC- Y/N) menu 3, by pressing scale you can change the temperature unit to °C or °F. Confirm with READ / ENTER.

Kruess Optronic Digital Refractometer DR 301-95

Salinity analysis can also be carried out using a handheld KRÜSS OPTRONICTM Digital Refractometer DR 301-95. Before starting inspect the prism window to ensure that it is completely clean. Before each measurement clean the window with a soft tissue. During the measurement the refractometer has to be placed in a horizontal position.

  • Preparation: Inspect the prism window to ensure that it is completely clean. Before each measurement clean the window with a lab tissue. During the measurement the refractometer has to be placed in a horizontal position.
  • Calibration: At least once a day, additionally after each change of the setting (e.g. moving of the instrument). Put approx. 1 ml of purified water (18 - 20°C) onto the prism and close the lid and press ZERO for 3 seconds. The calibration is completed when END is displayed.
  • Measurement: Put approx. 1 ml of sample onto the prism and close the lid and press READ / ENTER. Press scale to change the measurement units if necessary. Make sure to document the result in the respective analytical documentation and the sample itself in the respective expedition database mDIS.
  • Automatic Temperature Compensation (ATC): should be switched on for each measurement. If ATC is not displayed press FUNC- Y/N, select menu 2, press scale to switch the temperature compensation on and confirm with READ / ENTER.
  • Temperature Unit: select from the function-menu (FUNC- Y/N) menu 3, by pressing scale you can change the temperature unit to °C or °F. Confirm with READ / ENTER.