There are many cases where sample dilution seems to be adequate to get better measurement results:
Purpose for sample dilution:

  • Get high concentrations into measurement range.
  • Use the ideal measurement technology measurement range for electrodes.
  • Lower the influence of interferences.
  • Reduce the influence of sample colour and turbidity.

Key Issues:

  • What are the limits of dilution in unobserved online measurement analysis?
  • What are the implications of dilution for ISE measurements?

Setup of two steps dilution:
SEIBOLD COMPOSER with photometric unit. While the research results of dilution limits are the same for photometric and ISE measurement technologies (and others as well), we chose the photometric setup for test to get more precise and faster response.

Pump 1: Sample 1,3 ml/min Pump 3: Diluted Sample 1,3 ml/min
Pump 2: Water 40 ml/min Pump 4: Water 40 ml/min

Dilution factor: 1 / (1,3/41,3*1,3/41,3) = 1009.

Left picture shows that dilution works flawless and keeps the dilution ratio steady. These 6 different line levels (some multi measurements) show 6 different dilution ratios.

Right picture shows 6 different dilution levels from factor 400 to 1000. The line up is almost perfect.

Development of Dilution
Development of Dilution
Dilution Factors
Dilution Factors







RESULT: The online Analyser SEIBOLD COMPOSER can dilute up to 1:1000!

Limits of Dilution

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