Conductivity of Purified water in pharma 22

Conductivity: The conductivity in pharmaceutical water is a measurement of the “ability of water to conduct or pass the electricity”. Units of measurement of the conductance of water: Siemens per meter (µS/cm)Conductivity

The Conductance of Pharmaceutical Water

What is the need to measure the conductivity in purified water/Water for Injection or sterile water?

The answer is conductance measurement is the method to measure the ionic contents or free ions which are considered as an impurity in pharma grade water. So, if the conductivity is found low it means water is pure as per pharma grade.

The following are the factors that are considered during the checking of conductivity:

  • The higher the temperature of the water, the greater the ability of the water to conduct electrical charge that’s why conductivity is always reported at a reference temperature of 25 °
  • The unit of measurement of the conductance in the water is defined in micro siemens per cm (μS/cm)
  • Electrical conductivity in a raw can be quite variable, depending on the source of the incoming water. Typical values for conductivity in a river will be 100 – 2000 μS/cm.
  • As per USP purified water conductivity at 25 deg. C should not be greater than 1.3 µS/cm.

How do we check conductivity?

In pharmaceuticals Purified water is low conductivity (typically 5 micro-Siemen/cm or less). These applications demand a two-electrode conductivity sensor with a cell constant of 0.10 or less.

In pharmaceutical industries conductivty will check at the following stage:

  1. Check conductivity online at the water generation system & in the distribution Loop line.
  2. Periodically check by the QC department in the QC lab.

Also, there are lots of different devices in the market that you can use to measure water conductance, including:

  • Handheld Testers are meters that can be dropped into water to measure several characteristics, including conductance, salinity, temperature, and pH levels, among other things.
  • Portable water quality meters are also generally used in the field of research applications. These tools are used by water researchers in the environmental field since they are convenient to read outside.
  • In the laboratory, conductance can be measured with benchtop meters. They can obtain more accurate readings and are often larger than portable testers. Also, they calibrated periodically.
  • Inline meters are permanently positioned at specific points along a production line to monitor conductance and other aspects of water quality in real time.
  • Electrical currents are conducted through electrodes in order to assess specific liquid properties (e.g., how conducive they are).


Why pharma regulator makes compulsion to measure the conductance of water?

In the pharmaceutical industry water used as an excipient for the drug i.e., WFI, and also water used to clean the machine/equipment which is directly impacts the product quality and its life.

Or the pharma-grade water conductance needs to be measured to ensure high-quality end products are produced efficiently—thereby increasing profitability and minimizing risks.

Do you know how we calculate and measure conductance?

A probe and a meter are used to measure conductance. Voltage is applied across two electrodes in a probe immersed in sample water.

The voltage drop caused by water resistance is used to calculate conductivity per centimeter. The probe measurement is converted to micromhos per centimeter by the meter, and the result is displayed to the user.

NOTE: Some conductance meters can also measure total dissolved solids and salinity. The total dissolved solids concentration in milligrams per liter (mg/L) can also be calculated by multiplying the conductance result by an empirically determined factor between 0.55 and 0.9 (see Standard Methods #2510, APHA 1992).


As per the above details, conductivity is used as a measurement of the purity of the water and its checking in pharma-grade water is a control measure.

For more information on  water system-related setup,  please write us at:

1 thought on “Conductivity of Purified water in pharma 22”

  1. This article gives clear idea in support of
    the new viewers of blogging, that actually how to do running a blog.


Leave a Comment

error: Content is protected !! please mail your query on we provide you the printed copy.