Measurements; Measures For Correct Measurements; Calibrations; Zero Point Calibration - Mettler Toledo RA-510M Bedienungsanleitung

6.

Measurements

6.1

Measures for correct measurements

– Always calibrate the instrument at the temperature at which you measure the samples!
– Check the instrument with measurements of reference substances, e.g. from R. P. Cargille
Laboratories, Inc. USA.
– Use soft paper towels or washed gauze to remove the sample or dry the prism!
– Never use cotton wool as its fibers could adhere to the prism and influence the measurement!
– Always stir the sample on the prism carefully to allow air bubbles to escape!
– Use the vapor-proof lid if you measure volatile samples! (See Section 12)
6.2

Calibrations

You can calibrate the optical sensor of the RA-510M in two different ways, with the zero point
calibration (standard) or the 2-point calibration (for special applications).
Do not perform a zero point calibration until you have reset the line equation
NOTICE
of the 2-point calibration!
6.2.1

Zero point calibration

Before you measure samples, you must perform a zero point calibration with deionized
water: The RA-510M has stored in its memory the characteristic line of the optical sensor as
well as the refractive indices of H
corrects the zero point (offset) of the characteristic line. This zero point remains stored until
the next calibration.
– Press the Calib. key:
-CALIBRATION-
* Prism
-CALIBRATION-
** Set
RA-510M
METTLER TOLEDO
O for the temperature range of 15 to 40 °C. This calibration
2
Clear *
Temp. 20.00 °C
Press ENTER key
Water **
Temp. 21.09
Press ENTER key
The cell must not contain a sample!
– Press the ENTER key: If the prism
surface is not completely dry, the mes-
sage "Not dry while air calibration" is
printed out.
– Add approx. 0.2 mL deion. water to the
prism, e.g. with a polyethylene pipette.
– Close the cover and press the ENTER
°C
key:
The calibration now starts.
Measurements
9