Operation and Calibration of Karl Fischer Titrator SOP

By / Quality control / QC, SOP /

Calibration of Karl Fischer Titrator | Operation of lab india karl fischer titrator |

1.0 OBJECTIVE :
  • To provide a procedure for operation and calibration of Karl Fischer Titrator.
2.0 SCOPE :
  • This procedure is applicable to Lab India Instruments make Karl Fischer Titrator.
3.0 RESPONSIBILITY :
  • Quality Control Chemist and above
4.0 ACCOUNTABILITY:
  • Quality Control Head
5.0 PROCEDURE :

5.1 PRECAUTIONS

  • Ensure that the instrument is clean and free from dust.
  • Avoid touching lower part of the electrode.
  • Ensure that the instrument is located and maintained at a temperature below 30oC.
  • Dry all glassware before using for operation.
  • Close the reservoir with stopper Immediately after titrations are over to prevent atmospheric moisture entering in it.
  • After completing titration of first, next sample should be added without loss of time. It is advisable to keep the samples ready for adding one after another for titrating.

5.2 OPERATION (Determination of Water Equivalency Factor by DST)

  • Connect the instrument to main supply. Switch on the main supply.
  • Switch on the both switches available on back side of Karl Fischer Titrator and Fill/Drain pump.
  • Green coloured LED will glow on Fill/drain Pump while LCD screen on titrator will display (Neutralization)1) Y  and 2) N.
  • Fill dried methanol in bottle by pressing FILL switch of pump (about 50 ml).
  • Start the stirrer and set the speed at 3 RPM using up and down key.
  • Press 1) Y for neutralization.
  • After neutralization screen will show volume with beep sound.
  • Take print out.
  • Press ESC. Screen will show following option,
    • 1) Return
    • 2) print
    • 3) reprocess
    • 4) display result
    • 5) display status
    • 6) run
  • Press 6.
    • Screen will show 1) repeat 2) new run.
  • Press 2 (press 1 in case of repetition of sample).
    • Screen will show Method No. (1-50)
  • There are four method available for Determination of Water Content.
    • 1) Water
    • 2) Disodium Tartarate
    • 3) Solids
    • 4) Liquids
  • Press 2 for determination of water equivalency factor using DST and press enter.
  • Weigh about 150 mg of disodium tartarate and transfer to the bottle by removing stop cork.
  • Close the cork again after adding of DST to bottle.
  • Screen will show
    • 1) Run
    • 2) View
  • Press 1.
  • Enter identification no. and then press ENTER.
  • Add weight in mg, then again press ENTER.
  • As before the operation will stop on reaching the end point and beep sound will produce.
  • Take print out.
  • Press ESC to go back.
  • Press 6 for second time calculation of Water Equivalency Factor.
  • Screen will show 1) repeat 2) new run.
  • Add DST then press 1 for repeat.
  • Enter identification no. and then press ENTER.
  • Add weight in mg, then again press ENTER.
  • Repeat the procedure for 3 times with DST.
  • For result, press ESC, screen will show,
    • 1) Return
    • 2) print
    • 3) reprocess
    • 4) display result
    • 5) display status
    • 6) run
  • Press 4.
  • screen will show, Enter result no.
  • Enter result number and press enter.
  • (Note: Results are stored in descending order, i.e, for recent result press 10, for previous result press 9)
  • Screen will show
    • 1) Volume Display
    • 2) KF Volume (Which is Reading)
    • 3) Conc. (which is Water Equivalency Factor)
  • Manual Calculation of Water Equivalency Factor,
    • Water Equivalency Factor = 0.1566 x Weight of DST in mg / Volume Display

5.3 Determination of Water Content in sample

  • Press ESC. Screen will show following option,
    • 1) Return
    • 2) print
    • 3) reprocess
    • 4) display result
    • 5) display status
    • 6) run
  • Press 6.
  • Screen will show 1) repeat 2) new run.
  • Press 2.
  • Screen will show,
  • Method No.(1-50)
  • Press 3 for water determination of solid sample,
  • Press 4 for liquid sample and press enter.
  • Weigh specified amount of sample as per IP/BP/USP/IH specification and transfer to the bottle by removing stop cork.
  • Close the cork after adding of sample to bottle.
  • Screen will show
    • 1) Run
    • 2) View
  • Press 1.
  • Enter identification no. and then press ENTER.
  • Add weight in mg, then again press ENTER.
  • As before the operation will stop on reaching the end point and beep sound will produce.
  • Take print out.
  • Manual Calculation of the % of water content in sample as follows,
    • %  Water Content = Volume Display x Water Equivalency factor of KF x 100 / Weight of Sample taken in mg
  • Water Content in PPM =  % of  Water content x 10000

CALIBRATION

  • Calculate Water equivalency factor by DST as per procedure given in point no. 5.2.
  • Repeat procedure 3 times with DST and Calculate water equivalency factor for each DST.
  • Take a mean of 3 water equivalency factor.
  • Acceptance Criteria :
  • The water content of Karl Fischer reagent is not less than 4.0 and related standard deviation of three water content is not more than 1.0%.

For General information on karl fischer titration click below link:

Karl Fischer Titration
 6.0 ABBREVIATIONS:
AbbreviationExpanded form
mlMilliliter
KFKarl Fischer
Conc.Concentration
gmGram
mgMilligram
%Percentage
DSTDisodium Tartarate
LCDLiquid Crystal Display
ESCEscape

7.0 ANNEXURES:
Annex. No.Title
01Format for Calibration of Karl Fischer

8.0 SOP REFERENCES
  • Manual of Karl Fischer Titrator

END OF THE SOP

ANNEXURES :

Annex. No. 01 Format for Calibration of Karl Fischer