Metrohm KF Titrator operation, calibration and maintenance

1.0 OBJECTIVE 

To lay down the procedure for the operation, calibration and maintenance of Metrohm KF Titrator, Model 870 KF Titrino plus.

2.0 SCOPE

This SOP is applicable to Operate the Metrohm KF Titrator, Model 870 KF Titrino plus in Company Name.

3.0 BACKGROUND

NIL

4.0 RESPONSIBILITY

4.1 Analytical research personnel whoever is operating the Equipment.

4.2 Group Leader Analytical research to ensure proper and safe operation of the Equipment.

4.3 Head - Analytical research or his designee to ensure overall compliance.

5.0 PROCEDURE

5.1 Cleaning:

5.1.1 Clean the Instrument with a clean dry cloth. If required, clean with a cloth dipped in mild detergent solution followed by wiping to dryness with a dry cloth.

5.2 Operation:

5.2.1 Ensure that the instrument is connected to the stabilized power supply.

5.2.2 Switch on the main power supply.

5.2.3 Ensure that Karl Fischer reagent is present in adequate quantity for the day and Homogenize the reagent by shaking it well before starting the analysis.

5.2.4 Fill the dry molecular sieves in molecular sieve holders.

5.2.5 Clean the titration vessel well with methanol and dry it.

5.2.6 Grease the rim of the titration vessel to ensure that no moisture enters into the titration Vessel.

5.2.7 Fill the vessel with the required solvents to a level such that the tip of the electrode properly dips in to the solvent by pressing the ‘IN’ key provided on the 803 Ti stand.  

5.2.8 The Titrator starts filling the burette automatically and press and hold stop key to turn on KF titrator.

5.2.9 Enter the details in “Usage log book” (Annexure-1)

5.3  Determination of KF Factor using water. 

5.3.1 Prior to the determination of the water content of any sample(S) under test, determine the Titer of the KF reagent in duplicate by using the following method every day before  starting the analysis. Titer determination will be done once in a day or whenever the KF reagent is changed between the determination

5.3.2 Press the ‘METHOD’ key and Select TITER IPOL for determination of KF factor..

5.3.3 Press ‘Enter’. 

5.3.4 ‘Conditioning’ appears on the display. Wait until conditioning is finished.

5.3.5 Press ‘Start’ key on the keyboard. Add sample appears on the display.

5.3.6 Quickly remove the stopper of the titration vessel, weigh and transfer about 40 mg of purified water by using 50µL syringe into the titration vessel. Close the titration vessel immediately with stopper. Feed the weight of the water with the help of numerical keyson the keyboard in grams and press ‘Accept’.

5.3.7 Instrument starts titration,  Once titration is over, result appears as ‘Titer ….. mg/ml, on the display which gets printed on the printer, if connected. 

5.3.8 Repeat the same operation again for the second determination.

5.3.9 Mean value will be saved in the Titrator memory.

5.3.10 Ensure that the relative standard deviation (RSD) of the duplicate determination is not  more than 2%. Record the observations in “Standardization record for KF Reagent” Annexure-2. 

5.3.11 If RSD is more than 2% titration should be repeated.

5.4 Determination of water content in sample

5.4.1 Press ‘Method’ key and select ‘KFT IPOL’ appears on the display. 

5.4.2 Press ‘Start’ key on the keyboard. ‘Conditioning’ appears on the display.

5.4.3 After conditioning press ‘Start’ key on the keyboard.

5.4.4 Quickly remove the stopper of the titration vessel, add required weighed quantity of the Sample and close the vessel immediately with stopper. Ensure that no sample sticks to the wall of the vessel and to the tip of the electrode.

5.4.5 Feed the weight of the sample size with the help of numerical keys of the keyboard in grams and press ‘Enter’. 

5.4.6 Instrument starts titration, and the titrant volume appears as ‘KFR volume’ on the Display.

5.4.7 Once titration is over, results appear as ‘KFR Volume and Water in % is displayed, which gets printed on the printer if printer is attached. Otherwise note down the % w/w water content result manually in the record of analysis.

Note: For samples containing active ketonic groups, Pyridine should be used as solvent instead of methanol

5.5  Calibration with Disodium tartrate dihydrate 

5.5.1 Press the ‘METHOD’ key and Select KFT IPOL for determination of KF factor.

5.5.2 Proceed point no. 5.3.3 to 5.3.5.

5.5.3 Quickly remove the stopper of the titration vessel and add weighed quantity of about 150 mg of Disodium tartrate dihydrate into the titration vessel. Close the titration vessel Immediately with stopper. Feed the weight of the Disodium tartrate dihydrate with the help of numerical keys of the keyboard in grams and press ‘Enter’ 

5.5.4 Once titration is over, result appears as ‘Titer …..%’ on the display which gets printed on the printer, if connected.

5.5.5 Repeat the same operation for four more determinations.

5.5.6 Enter the details in “KF Titrator –Repeatability Test” Annexure-3

5.5.7 Acceptance criteria : Water content in % should be between 15.66 ± 0.30 w/w for disodium tartrate dihydrate. the relative standard deviation shall be not more than 2%. 

5.5.8 Calibration Frequency : Once in 6 months and after any major maintenance job.

5.6  Calibration of Burette volume

5.6.1 Keep the reagent sucking tube in purified water at temperature 25°C and rinse the burette following the steps given below.Use ‘DOS’ key to empty the burette.Use ‘STOP/fill’ key to fill the burette.Repeat the above operation and fill the burette with purified water.

5.6.2 Take Volumetric Flask (Class A) on weighing pan and tare the weight and dispense 1mL of water and take the weight.

5.6.3 Tare the weight of beaker and repeat the process by increasing volume 9 more times (E.g.: 2, 3, 4mL…)

5.6.4 Record the observations in “Calibration record for KF Titrator-Burette” (Annexure-4)

5.6.5 Acceptance Criteria: The rel. error shall be not more than 0.20%. 

5.6.6 Calibration Schedule: Once in 6 months and after every major maintenance job.

5.6.7 After completion of the burette calibration, rinse the burette with Methanol three times And once with KF reagent and fill it KF Reagent.

5.6.8 Dry the molecular sieve once in a month at 105°C for 3 hours. The molecular sieve holder id to be labeled (Annexure-5) after filling with dried molecular sieve.

5.7 Calibration of KF Titrator Linearity:

5.7.1 Press the ‘METHOD’ key and Select KFT IPOL for determination of KF factor.

5.7.2 Proceed point no. 5.3.3 to 5.3.5.

5.7.3 Quickly remove the stopper of the titration vessel and add weighed quantity of Purified  water using 50µL/100µL syringe into the titration vessel. Close the titration vessel. Immediately with stopper. Feed the weight of the water taken in grams with the help of numerical keys of the keyboard in grams and press ‘Enter’ 

5.7.4 Once titration is over, result appears as ‘Titer consumed mL’ on the display which gets printed on the printer, if connected.

5.7.5 Repeat the same operation for four more determinations.

5.7.6 Enter the details in “KF Titrator –Linearity Test” (Annexure-6)

5.7.7 Acceptance criteria : Correlation Coefficient NLT 0.999

5.7.8 Calibration Frequency : Once in 6 months and after any major maintenance job. NOTE:   Calibration shall be carried out with in ±7 days of calibration due date

5.8  Maintenance:

5.8.1 Ensure that the electrode is clean. (Clean the electrode with cotton/ tissue paper moistened with methanol.

5.8.2 Always electrode should be dipped in methanol and do not allow to dry.

5.8.3 Instrument manual should be followed for any observed faults. Respective service engineer shall be called for any technical problem. 

7.0 VERSION HISTORY

8.0 ANNEXURES     

Annexure-1   Usage logbook for KF Titrator  

Annexure-2   Standardization record for KF Reagent   

Annexure-3   KF Titrator –Repeatability Test 

Annexure-4   Calibration record for KF Titrator-Burette

Annexure-5   Label for ‘Molecular Sieve

Annexure-6   KF Titrator –Linearity Test