Operation of Milli-Q-Water System

  1. Objective

To lay down a procedure for Operation of Millipore Water Purification System

  • Scope

This SOP is applicable in Quality Control for operation of Millipore water purification system.

  • Responsibility

QC Chemist                : Follow the procedure and maintain record as applicable.   

  • Accountability

Head Quality Control  : System Compliance

  • Procedure:                                                                                                                  
    • Use Milli-Q water for all type of analysis purpose like Assay, standard solution, test solution for HPLC, UV and preparation of other standards etc.
    • To check the Milli Q Water quality select menu, then select Water quality and at last select Milli Q Water quality. Display shall give current information of Milli Q Water like TOC, resistivity, temperature. Check pH, conductivity and TOC on daily basis before use.
    • Check the pH of Milli-Q water offline and record in Annexure-I. pH should be between 5.0 to 7.0
    • Record the conductivity and TOC of Milli-Q water online and record. The limit for conductivity should be NMT 1.3µs/cm and TOC should be NMT 500 ppb.
    • Calibration of pH sensor, conductivity sensor and TOC sensor shall be done by outside vendor on annual basis.
    • Instrument Panel:
      • Details of instrument panel is as below-
  • Dispensing of Milli-Q Water:
    • Switch on the main power supply and then LCD Screen of the Water purification System, which is located at the Right top from the front side of the instrument, is displayed.
    • The Right key button is used to move to the next screen.
    • The Left key button is used to move to the previous screen.
    • The Up key button is used to scroll up in a menu.
    • The Down key button is used to scroll down in a menu.
    • The Validate Key button is used to confirm a parameter modification.
    • Verify the LED Light, when the screen is in READY mode.
    • Green color- Indicates System is operating within specification.
    • Yellow color – An Alert is present.
    • Red color – An Alarm is present.
    • When the screen is in Ready Mode, Select the Items using Up Down keys for Navigation.
    • For the Water dispensing put the cursor on volume and press the right key to choose the desired volume of Water to be dispensed.
    • Remove the blue or transparent cap provided to the spout of the dispensing valve, and place a flask or beaker for collecting Water below it.
    • Press Validate key to start the dispensing.

After about a minute bring down the trigger of the dispensing valve to the horizontal position and ensure that Water flows out through the spout.

  1. Bring back the trigger to its original vertical position after collecting the required quantity of Water.
    1. Ensure that the flow of Water is stopped when the trigger is in the vertical position and the LCD displays READY Mode.
    1. Clean Water Purification System (Milli Q Water System) and surrounding area after use.
    1. Sanitizing the RO Cartridge(s) and Tank
      1. RO cartridge sanitizing is required to prevent bacteria development in the cartridge. To maintain optimum RO performance, perform sanitization every month or when the alert message is displayed: “Alert message = PERFORM RO CL2 CLEANING”
      1. Go to STANDBY mode and allow the water system to depressurize for a few seconds. Use the sanitization port removal tool and loosen the cap. Remove the cap.
      1. Place a chlorine tablet in to the sanitization port. Put the cap back and hand tighten it. Go to STANDBY Mode, select Sanitize/Clean, then select RO CL2 Cleaning and press validate key.
      1. The RO CL2 cleaning will take approx 20 min. When the cleaning is finished, the water system automatically goes in to READY Mode.
      1. Fill the sanitization record.
  2. Annexure (S)


  • Reference (S)


  • Glossary           

SOP                : Standard Operating Procedure

QC                  : Quality Control

QA                   : Quality Assurance

RO                  : Reverse Osmosis

TOC                : Total Organic Carbon

µs/cm              : Micro Siemens/Centimeter

ppb                  : Part Per Billion

  • Revision History
Rev. No. Details of changes Reason for change  

Bhanu Pratap Singh


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