Spectrophotometric Color Determination at 420 nm

Materials and Reagents

Product No. 1.16754.9010 Water for analysis EMSURE® or distilled water
Product No. 1.14944.0001 Rectangular cells 50 mm or
Product No. 1.74011.0001 Rectangular cell 100 mm (Prove 600 only)

Product No. 1.73016.0001 Spectroquant® VIS Spectrophotometer Prove 100 or
Product No. 1.73017.0001 Spectroquant® UV/VIS Spectrophotometer Prove 300 or
Product No. 1.73018.0001 Spectroquant® UV/VIS Spectrophotometer Prove 600
Membrane filters, cellulose nitrate, pore size 0.45 µm, diameter 50 mm
Conical flasks 250 mL
Ultrasonic bath



Spectrophotometric Color Determination at 420 nm

Measuring Range

Method No. 2550: 0 – 50 IU7.0

Working Instructions

Sample Preparation

  • Mix the sample thoroughly.
  • Weigh 50.0 ± 0.1g of the sample into a 250 mL conical flask.
  • Add 50.0 ± 0.1g of distilled water (Water for analysis EMSURE® is recommended) and dissolve the sample by swirling at room temperature.
  • Vacuum-filter the pretreated solution over a membrane filter into a clean and dry conical flask.
  • Degas the solution for 3 minutes in the ultrasonic bath.

Measure the % RDS (refractometric dry substance) of the solution to an accuracy of ± 0.1 g/100g (according to ICUMSA Method GS4/3-13).

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 after entering the %RDS value. For zero adjustment fill a corresponding rectangular cell with distilled water or water for analysis.

After prompting, place the rectangular cell filled with water 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 the method (2550, "ICUMSA Color GS2/3-10“) from the method list of the Spectroquant® Prove. Enter the RDS value in %. Confirm with OK.
  • Press START to start the measurement mode. Perform a zero adjustment (procedure see “Zero adjustment”).
  • Transfer the sample solution into a corresponding cell. Place the cell into the cell compartment. The measurement is performed automatically.
  • Confirm measurement with OK. The IU7.0 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.

Note: The result is calculated according to ICUMSA GS2/3-10(2011) chapter 8.1 and ICUMSA SPS-4 table B (Sucrose; 20 °C). Individual ICUMSA methods or references are available online within 48 h: www.icumsa.org under “Methods book”.

Short measuring procedures on Spectroquant® Prove instruments are described in the Analytical Procedures and Appendices, available online on our website.