SOP FOR OPERATION AND CALIBRATION OF NEPHELOMETER

1.0       Objective:

            The objective of this standard Operating Procedure is to lay down the procedure for

            Operation and Calibration of Nephelometer.

2.0       Scope:

            This SOP covers operating and calibration of Nephelometer .

3.0       Responsibility:

            Jr. Research Officer, Research Officer: Responsible for operation, calibration and  

            maintenance of the instrument as per procedure.

            Head of Department: Responsible for calibration and maintenance, timely as per               

            schedule.

            QA Officer/QA Manager: Review the records and governing the document.

4.0       Procedure:

4.1       Switch ON the instrument (back side switch).

4.2              Open the lid of the sample compartment & insert a test tube filled with the distilled water

            into the sample compartment then close the lid.

4.3       Rotate the switch of “set 0” to get “0” on LCD.

4.4       Open the lid, replace the test tube of distilled water by Formazine Std .Solution, and close

            the lid.

4.5       Rotate the switch of “Set 100” to get “100” on LCD.

4.6      Take the reading of sample in same way after setting standard.

4.7      Switch of the instrument.

Note:   Wash the test tube with distilled water after taking result.

5.0       Calibration Procedure:

            Solution 1:- Weigh accurately 5.0 g of Hydrazine Sulphate in 500 ml volumetric flask

            and add distilled water to make up to the mark. Leave the mixture to stand for 4 hours.

            Solution 2:- Weigh accurately 50.0 g of Hexam-Ethlenetetramine in 500ml volumetric

            flask and add make up the volume up to the mark with distilled water.

            Mix the equal volume of solution 1 and 2 form Formazine Turbidity Concentrate   

            Allow to stand in a closed container at 25º C to 30º C for 48 hrs to produce insoluble 

            while turbidity corresponding to 4,000 NTU (This solution is stable for 2-3 Months).

            Formazine Standard -100 NTU :- Dilute 25 ml of  the Formazine Turbidity Concentrate 

            to one liter with turbidity free distilled water to obtain 100 NTU Formazine Standard  for     

            setting 100 of  the instrument. (This Solution should be prepared weekly)

6.0              Routine Maintenance:

6.1              Clean the instrument with dry cloth.

6.2              Clean sample tube with methanol and than with water.

6.3              Clean the sample holder with dry cloth.