Kemtrak DCP007 & The ICUMSA Colour Scale

The methods, applications, and benefits of the Kemtrak DCP007 include the following:

•    ICUMSA Methods GS 1/3-7, GS 2/3-10 and GS 2/3-10
•    Determination of the solution colour of white, brown, and raw sugars as well as coloured syrups
•    Decolourisation of glucose syrups
•    A charcoal filter alarm
•    Manufacturing quality and control
•    Real time in-line continuous measurement
•    A zero maintenance LED light source that never needs replacing.

What is the ICUMSA Colour Scale and how is it used in sugar production?

The International Commission for Uniform Methods of Sugar Analysis (ICUMSA) describes a range of methods for the colorimetric determination of filtered sugar suspensions at known concentrations (Brix values).

The ICUMSA colour scale is used to measure the grade and quality of the sugar. The colour of sugar directly relates to the degree of refining – raw sugars being dark brown in colour whilst highly refined sugars are white in colour. The ICUMSA colour scale is a measurement of the yellowness of the sugar resulting from residual molasses not removed in the refining process and can be used to monitor and control the manufacturing process.

How can the Kemtrak DCP007 be applied to this process?

The Kemtrak DCP007 process photometer has a high-performance long-life LED light source, precision optical filters and robust fibre optics that results in an ICUMSA colour analyser with outstanding performance and reliability.

The Kemtrak DCP007 process photometer is recommended to accurately measure ICUMSA colour. The Kemtrak DCP007 employs proprietary dichromatic measurement technology that compensates for particulates, allowing accurate colour measurement without the need for filtration.

Due to the proprietary dichromatic four channel measurement technology, particulates in the process media can be compensated for in real time providing an accurate measure of colour without the need for filtration. A primary “absorbing” wavelength then accurately measures colour changes in the process medium, while a second reference wavelength, which is not absorbed by the process medium, compensates for particulates and/or fouling of the optical windows.

Since optic fibres are used to transfer light to the measurement point and back, the measurement cell contains no electronics, moving parts or sources of heat that result in condensation on the optical surfaces. Standard measurement cells are machined in sanitary grade stainless steel with sapphire windows.

How should I set up and configure the Kemtrak DCP007 for my own work?

ICUMSA recommend the absorption of light at 420nm for white and light-coloured sugars and 560nm for darker sugars. 720nm is recommended for the reference wavelength to measure and compensate for the turbidity of the solution.

The Kemtrak DCP007 process photometer will accurately measure ICUMSA colour for a known concentration sample using the Brix value (degrees Brix or °Bx). ICUMSA colour is calculated as follows: ICUMSA Colour = 1000 × As/b c
Where:
As = absorbency of the solution (DCP007 primary measurement)
b = the optical path-length (cm)
c = concentration (g/mL) (using the Brix value).

Colour score is expressed in RBU (reference base units) per ICUMSA standard method(s). Where an end user specific base reference is used, the DCP007 can be adjusted accordingly.

The process Brix value, measured using a separate density or refractive index analyser, is input into the Kemtrak analyser through a 4-20mA analogue input to correct for differences in sugar concentration.

As an alternative where a live density measurement is not available, process Brix values can be manually entered into the analyser.

The Kemtrak DCP007 should be configured for the desired measurement range for maximum resolution and accuracy.

An optical path-length of at least 10 cm or more is recommended for low colour white sugars, whilst shorter path-lengths are necessary for darker sugars. Please contact us directly for specific configuration details regarding measurement wavelength and selection of optical path-length for the desired measurement range.

Where can I find out more about the Kemtrak DCP007?

Head over to our dedicated webpage on the Kemtrak DCP007 for more information on this popular instrument.

To discuss your requirements or for a free, no-obligation quote, please call us on: 01442 876777 or email: [email protected].