SOP On General Laboratory Practices
Objective: To lay down a procedure for General Laboratory Practices in the QC laboratory.
Scope: This SOP describes the procedure for General Laboratory Practices in the QC laboratory.
Responsibility: Chemist or above of Quality Control laboratory.
Accountability: Head – Quality Control.
Procedure: In Quality Control department, there shall be separate wings for wet lab, instrument lab, GC lab, stability room, microbiology etc. and each wing shall be interconnected.
Lightning, Temperature and Ventilation shall be appropriate.
Working temperature shall be 15ºC to 25º
Temperature monitoring of Instrument Lab, Wet Lab, GC Lab and Chemical store room shall be done at least twice daily and record shall be maintained.
Working area should be clean and tidy at all time.
All entries shall be done online.
If any mistake has been occurred during entry in logbook or other document then make single strikethrough on wrong entry with initial and date.
All instrument calibration and preventive maintenance record shall be done periodically and documented as per schedule.
All instruments operation, calibration and cleaning SOPs and other SOPs shall be displayed near by the relative instruments.
SOPs training shall be given by QC Head or nominee to all laboratory personnel and their training record shall be maintained as per SOP.
Before using instrument analyst shall check the status label / calibration label of instrument then start analysis.
All QC persons are responsible to maintain the laboratory safety rules and discipline as per SOP.
During analysis any laboratory incident observed SOP shall be followed.
Points to be kept in mind while doing analysis:
Class ‘A’ glassware received with calibration certificate shall be used for quantitative analysis.
While using class ‘B’ glassware be sure that they are properly calibrated.
Always use balances, which are calibrated periodically against absolute standard weights.
Never leave balance doors open.
While weighing, the quantity actually used must not deviate by more than 10 % from that stated in the test procedure of the individual.
Operating range shall be affixed on each balance.
Do not weight beyond the operating range for quantitative analysis. Incase of qualitative analysis or preparation of system suitability solution, which is not used for calculation of results, might be weight less than operating range.
During pipetting if sample is colourless / slightly colored and clear, slowly drop the lower meniscus of the sample to the mark of the pipette and if it is highly coloured then slowly drop the upper meniscus of the sample to the mark of the pipette.
Keep the pipette in a vertical position and then touch against the wall of the receiving vessel to drain the tip.
While observing the meniscus always keep the pipette in vertical position at the level of eyes.
Never blow out the tip of the pipette while draining.
For non-viscous samples, allow the pipette to drain for about 15 sec. after the liquid has been dispensed.
For viscous samples, allow the pipette to drain for about 45 sec. after the liquid has been dispensed.
While doing dilutions, be careful not to lose sample during transfer, such as liquid dripping out of a pipette tip before the tip is in the receiving vessel
When the combination of two substances is either exothermic or endothermic, allow the mixture or solution to come to room temperature prior to achieving final volume.
While using microlitre pipettes, be sure that they are properly calibrated.
While doing filtration following precautions should be taken:
For gravity filtrations choose an appropriate size of filter paper (as per requirement) from an approved vendor. Fold it in cone shape and place it into a suitable clean funnel.
Place the funnel stem into the receiving vessel such that the bottom tip of the stem touches the wall of the receiving vessel.
Pour few ml of sample to be filtered on the filter paper and discard the filtrate.
Continue the filtration by pouring sample in portions, allowing each portion to filter before adding the next.
Do not fill the funnel (with filter paper) to more than about 90 % of its capacity.
For vaccum filtration take a clean vaccum filtration cup.
Place the membrane filter in the filtration cup.
Wet the membrane filter with appropriate solvent.
Place the filter assembly on a clean vaccum filter flask and connect the sidearm of the flask to a source of vacuum.
Filter the sample portions, adding each subsequent portion after the previous one has been approximately 80 % filtered. Do not allow the filter media to go dry between portions.
On completion of filtration, break the vaccum by releasing the vacuum from the flask sidearm slowly and gradually.
Remove and disassemble the filter funnel assembly, discard the membrane filter, and clean the filter assembly for subsequent use.
During centrifuging place the tube in the centrifuge head’s tube holders, always use an even number of tubes, such that they are placed across each other so that the weight of material in the centrifuge is evenly balanced. If only one sample is to be centrifuged, then counterbalance it with a tube containing water.
Make sure that the centrifuge cover is closed.
During titration fill the burette with the titrant up to the 0 ml mark.
Always use standardized titrant for titration.
Perform the titration slowly, drop by drop towards the end point.
Continuously swirl the sample/blank containing flask while performing titration.
Basic Techniques for performing TLC:
Always use a TLC plate 1.5-2.0 inch more in length than the distance to be developed.
Always prepare fresh mobile phase sample and standard solutions and spraying reagents.
Always spot at a distance of 1.0- 1.5 cm above the baseline of the plate.
The mobile phase level in the chamber should not be more than the application line of the spots on the plate.
Place the plate straight or with the least angle, in the TLC chamber for faster and better development.
Special Precautions while using vacuum oven:
Close the vacuum inlet and turn off the vacuum pump. Then bleed off the vacuum gradually over a period of a minute or two so as not to disturb samples contained within the oven.
When pulling vacuum on vessels containing volatile or corrosive solvents, place a cold trap or scrubber between the vacuum source and the vessel to which vacuum is being applied. Whenever vacuum is being applied to glassware, be sure that the glassware used is rated for use with vacuum. Failure to do so may result in serious injury due to glassware implosion.
Handling Precautions during Instrumental analysis:
Before starting the analysis of HPLC, ensure that respective solvents and inlets inserted as per the requirement given in the respective STP’s.
Sequence shall be prepared by the analyst as per the respective STP.
Sequence shall be verified by the supervisor before starting the analysis a day shift. Incase any sequence started after day shift, analyst shall verify the sequence himself and start the sequence and attached the sequence with raw data.
During analysis, analyst shall verify each and every injection. If any discrepancy observed, ‘Handling of lab incident’ SOP shall be followed.
If any sequence is running in night shift and finish in next shift or if samples are being loaded in long sequence then next shift analyst shall verify the sequence for its authenticity. If any discrepancy observed then followed the SOP (Handling of lab incident).
System suitability procedures shall be followed wherever required.
After running the sequence, if any discrepancy is found (for e.g. absence of vial, system suitability failure etc.) then, SOP for lab incident shall be followed.
For analysis on GC, before starting the analysis, ensure that the pressure of gases is within limits.
No leakage of gases should be there.
If any malfunctioning is occurs in any instrument, deviation shall be raised as per SOP on Handling of deviations.
Desiccants like silica gel and molecular sieves shall be dried and in proper working condition.
Volumetric solution bottles, reagents bottles, mobile phase / diluents bottles and other solution bottles should be properly labeled.
During analysis analyst shall be labeled or marked the glassware with initial and date and write the sample details like sample name, batch no. etc.
Analysis shall be done as per respective specification and STP.
Not more than one entries shall be allowed in one row in log book and one line shall be left blank in to instrument and inward log book to ensure readability of each entry.
Maintain the record of operational activity of instruments in instrument logbook as per SOP.
Inject the sample immediately after preparation, not hold it more than 15 minutes in case of related substances test.
Reporting procedure for related substances test:
In related substances test, if % impurity is less than Quantitation Limit or reporting threshold then result shall be reported as BQL (Below Quantitation Limit) or BRT (Below reporting threshold), which ever is given in the STP.
Incase if known impurity does not elute then it shall be reported as ND (Not Detected).