Analytical Method: Determination of the deterioration of bleachability index (DOBI) of raw palm oil acc. to DIN EN ISO 17932:2011

Materials and reagents:
Cat. No. 173017  Spectroquant® UV/VIS Spectrophotometer Prove 300 or
Cat. No. 173018  Spectroquant® UV/VIS Spectrophotometer Prove 600
Cat. No. 104718  Isooctane for spectroscopy Uvasol®
Cat. No. 100784  Rectangular cells quartz 10 mm
Volumetric flasks, class A, volume range 25 ml to 250 ml
Analytical balance 0.001 g
Paper filters


Method and measuring range:
Method No. 2524
0 – 4.00 DOBI


Sample preparation:
Melt the sample at 60 - 70 °C and homogenize.
If conterminations are present, filter the sample over a fast filtering paper.


Weigh between 100 mg and 500 mg of sample into a 25-ml volumetric flask.

Add a few millilitres of isooctane and dissolve the sample at room temperature. Subsequently make up the contents of the volumetric flask to the mark with isooctane and mix.
Filter turbid solutions over a paper filter.


Zero adjustment:
For each measurement series, a zero adjustment is required.
It is recommended to use the same cell for zero adjustment and for sample measurement.
The zeroing procedure for the measurement series is automatically prompted by the instrument.

For zero adjustment fill 10-mm rectangular quartz cell with isooctane.
After prompting, place the rectangular cell filled with isooctane in the cell compartment, the zero adjustment is executed automatically.
Confirm the implementation of zero adjustment with "OK".
The zero adjustment is valid for the entire measurement series.


Measurement procedure:
Select method 2524 "DOBI (palm oil)" from method list.

Prior to the measurement of the first sample the system automatically prompts a zero adjustment (procedure see "Zero adjustment").

Transfer the sample solution into a 10-mm rectangular quartz cell and place the rectangular cell into the cell compartment, the measurement is performed automatically.
Confirm measurement with "OK".
The DOBI value is shown in the display.

Press "START" to start the measurement procedure for the next sample. The system does not prompt a repeat of the zero adjustment.




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