ET125  General Purpose C4D Monitor Headstage

ET125 General Purpose C4D Monitor Headstage
ET125 General Purpose C4D Monitor Headstage
  • General purpose conductivity monitor
  • Measures a wide range of conductivities
Unit Price: $ (USD) 495.00


The ET125 can be used to record the conductivity of a solution flowing through tubing with an outer diameter of 1/16 inch (1.6mm). Installation is easy as the customer’s tubing is simply slid into the headstage. It must be connected to either the ER225, ER815 or ER825 hardware units.

The sample doesn't come into contact with the detector electrodes so it is easy to analyse hazardous, corrosive or radioactive liquids. There is no carryover or memory effect from the previous sample. There is no electrode deterioration or polarization.

The ET125 can record conductivities between 20 µS/cm and 200 mS/cm, depending on the inner diameter of the tubing being used. It can be used with many tubing materials, including PEEK and PTFE (Teflon) etc.

The ET125 is in the same family as the:

  • ET130 IC/HPLC C4D Detector Headstage.
  • ET131 Configurable C4D Detector/Monitor Headstage.

The gap between the C4D electrodes is relatively large in the ET125 when compared to the ET130. This enables the ET125 to measure higher conductivities, especially when it is used with tubing with a small internal diameter.

Research Areas

Application Notes


  • Quantitative Characterisation of Conductive Fibers by Capacitive Coupling.  Andres Ruland, Rouhollah Jalili, Attila J. Mozer, and Gordon G. Wallace.  Analyst, 2017.  DOI: 10.1039/C7AN00442G
  • Suspension Catalysis in Slug Flow Microreactor – Experimental and Numerical Investigation of Mass Transfer.  Frederik Scheiff, Frank Neemann, Sylwia J. Tomasiak, Prof. David W. Agar.  Chemie Ingenieur Technik, 86, 4, 504–518, 2014.  DOI: 10.1002/cite.201300131
  • Exploring the possibilities of capacitively coupled contactless conductivity detection in combination with liquid chromatography for the analysis of polar compounds using aminoglycosides as test case. Péter Jankovicsa, Shruti Chopraa, Mohamed N. El-Attuga, Deirdre Cabootera, Kris Wolfsa, Béla Noszálb, Ann Van Schepdaela, Erwin Adams.  Journal of Pharmaceutical and Biomedical Analysis.  2014. DOI: 10.1016/j.jpba.2014.12.015
  • Contactless Conductivity: An HPLC Method to Analyze Degree of Methylation of Pectin.  Gary A. Luzio, and Randall Cameron. Proceedings of the Florida State Horticultural Society, 123, 213–216. 2010.


Photos[ click on the thumbnails below to view large images ]

ET125-130-131 no cable ET125-130-131 with ruler length ET125-130-131 with ruler width ET125-130-131 no cable


A procedure for C4D analysis in PowerChrom software
The C4D Profiler in PowerChrom software to optimise C4D settings
Using the C4D Detector software to control the ER125 C4D Detector

View more related videos on the Screencast Training Videos Wiki


Conductivity ranges:

  • 20 µS/cm to 2 mS/cm when using tubing with 500 µm internal diameter.
  • 200 µS/cm to 20 mS/cm when using tubing with 250 µm internal diameter.
  • 2 mS/cm to 200 mS/cm when using tubing with 125 µm internal diameter.

Electrode ID: 1.6 mm

Electrode Gap: 9 mm