SOP for Cleaning Laboratory Glassware

This document details the procedure for laboratory glassware cleaning to the intended users or concerned personnel. It is the policy of Pharmaceuticals  that a written procedure shall be followed for laboratory glassware cleaning and detailed to the intended users or concerned personnel for awareness and implementation.

This SOP is applicable at the time of maintaining the cleanliness of glassware used in the laboratory.


Persons along with their responsibilities are given below:

S. No




Executive  - Corporate Quality Assurance

To prepare and follow the SOP accordingly. Maintain the record as per SOP.


Trainee Analyst/ Jr. Analyst/ Analyst/ Sr. Analyst

To follow the SOP accordingly


Manager – Quality Control

To ensure implementation of SOP.


Manager - Quality Assurance

To ensure implementation of SOP.


Manager         -      Corporate Quality Assurance

To ensure implementation of SOP.

Laboratory Glassware



5.1.1 When washing, soap, detergent, or cleaning powder (with or without abrasive).

5.1.2 Full set of brushes-To fit large & small test tubes, burettes, funnels, volumetric flasks of various sizes, and conical flasks cleaning

5.2.1 Wash lab glassware as quickly as possible after use. If a thorough cleaning is not possible immediately, soak glassware in water. Most new glassware is slightly alkaline. For the precision chemical tests, new glassware should be soaked for 1 hour in acid water (1 % hydrochloric acid or nitric acid) before washing. Finally, rinse with purified water

5.2.4  Removing Grease Grease is best removed by boiling in weak solution of sodium carbonate. Acetone or any   other fat Solvent may be used. Silicone grease is most easily removed by soaking the stopcock plug or barrel for 2 hrs in  warm Decahydronapthalene Drain & rinse with acetone or use fuming sulfuric acid for 30 minutes. Be sure to rinse off the entire Cleaning agent. Rinse with tap water if tap water is hard, and then use. Further, rinse with purified water.


5.3.1 Remove the stopcock or rubber tip & wash the burette with detergent & water.

5.3.2 Rinse with purified water & dry.

5.3.3 Wash the stopcock or rubber tip.

5.3.4 Before a glass stopcock is placed in the burette, lubricate the joint with stopcock lubricant.

5.3.5 Use a small amount of lubricant & burettes should always be covered when not in use.

Culture Tubes

Culture tubes that have been used previously must be sterilized before cleaning. The best method for sterilizing culture tubes is by autoclaving for 30 minutes at 1210C (15p.s.i. Pressure).

 Media that solidifies on cooling should be poured out while the tubes are hot. After the tubes are emptied, brush with detergent & water, rinse thoroughly with tap water, rinse with purified water, place in the basket & dry.

Dishes & Culture Bottles

Sterilize & clean as detailed under culture tubes. Wrap in heavy paper or place in a petri dish can . Sterilize in the autoclave or dry air sterilizer.

Blood cell counting pipettes

After use, rinse thoroughly with cool tap water, purified water, alcohol, or acetone, & then ether.

Dry by suction.

To remove particles of coagulated blood or dirt, a cleaning solution is used. Sodium hypo chloride or hydrogen peroxide may be used. In difficult cases, use concentrated nitric acid.

It is best to fill the pipette with the cleaning solution & allowed it to stand as such overnight. Blood Clotting pipettes should be sterilized in an autoclave

Serological Tubes

Serological tubes should be chemically clean, but need not be sterile. Serological tubes with blood specimens must be chemically clean & sterilized.

To clean & sterilize tubes containing blood, discard the clot in a waste container & place the tubes in a large basket. Put the basket in a large boiler. Cover with water, add a fair quantity of soft soap or detergent & boil for 30 minutes. Rinse the tubes, clean with brush, rinse & dry with the usual precaution.

Slides & Cover Glass

Slides should be washed, placed in glacial acetic acid for 10 minutes, rinsed with purified water & Wiped dry with clean paper, towel, or cloth. Once the slides have been washed, place them in a wide jar of alcohol. As needed, remove from the jar & wipe dry. If the slides are stored dry, wash them with alcohol before use.

5.8 USE OF CHROMIC ACID (Monthly Cleaning of Pipettes, Burettes, Volumetric Flasks)

5.8.1 If glassware becomes unduly clouded or dirty or contains coagulated organic matter, it should be cleaned with a chromic acid cleaning solution.

5.8.2 Chromic Acid cleaning Solution: Use hard borosilicate glass apparatus for its preparation and storage. powdered commercial or technical grade sodium dichromate or potassium dichromate. Weigh 20 gm of powder sodium or potassium dichromate in one-liter beaker; add a little purified water (about 10 ml.), sufficient to make a thin paste. Place it in an ice bath. Slowly add approximately 150ml of commercial concentrated sulphuric acid with stirring. Exercise all safety precautions while preparing the solution as it is very corrosive.                Transfer to a glass stoppered bottle.

5.8.3 When chromic acid is used the glassware may be rinsed with the cleaning solution.

5.8.4 Glassware may be filled with chromic acid solution & allowed to stand. The time duration, it is allowed to stand depends on the amount of contamination on the glassware.

5.8.5 It is good practice to place the stock cleaning solution as well as glassware being treated, in a flat glass pans or pans made of lead or coated with lead or plastic polymer pans determined compatible with chromic acid.

5.9 Handling & Storing

5.9.1 To prevent breaking when rinsing or washing pipettes, cylinders, or burettes, be careful not to let the tip hit the sink or water tap.

5.9.2 Dry test tubes, culture tubes, flasks & other glassware by handling them on a wooden peg or placing them in a basket with their mouths downward & allowing them to dry in the air.

5.9.3 For the sensitive microbiologic assay, meticulous cleaning must be followed by rinsing 12 times with distilled water.

5.9.4 Store glassware in specially designed racks. Avoid breakage by keeping separated.

5.9.5 Do not store the alkaline liquid in volumetric flasks or burettes. Stoppers or stopcock may stick.

5.9.6 Dichromate (Chromic Acid) should be handled carefully.

5.9.7 Brushes with wooden or plastic handles are recommended as they will not scratch or abrade the glass surface. Serious scratches on glass make it more prone to break during the time of usage.

Standard operating procedure for training employees


 SOP:           Standard Operating Procedure

 SOP:           Standard Operating Procedure

 QA:           Quality Assurance

 QC:           Quality Control

No. :           Number

>SOP for Safety in Laboratory 


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