OHS026
1. Completed by: Mukesh Raipuria
Safe work procedure
Staff/Student number:3306134
The Writing Safe Work Procedures Guideline (OHS027) should be consulted to assist in the completion of this form
Faculty/Division: Medicine
Document number
School/Unit: School of medical sciences/Department of Pharmacology
Initial Issue date
05/07/2011
Current version
1.0
MNG-SWP-14
Current Version
Issue date
05/07/2011
Next review date
07/2013
2.Safe work procedure title and basic description of activity
Title: Determining and adjusting the pH of laboratory solutions.
Description: To ensure the safe pHing of solutions in the Laboratory
3.List Hazards and risk controls as per risk assessment
Associated risk
assessment
number and
location: RA_pH
Meter_ WW 214
Hazards
Electrical shock
Chemical hazards
Impact
Controls
Tag certifying the electrical conformity from UNSW
Use of standard PPE ( gloves, gowns and safety glasses)
Staff training
4.List resources required including personal protective clothing, chemicals and equipment needed
pH meter
pH calibration buffers (Primary and Secondary)
Distilled water
Kim-wipes
NaCl (0.1M, 1M)
HCl (0.1M, 1M)
Saturated KCl solution
Magnetic stirrer and stirrer bars
Fume cupboard
Always wear long sleeve lab gowns, latex gloves and eye protection when working in the Laboratory.
5.List step by step instructions or order for undertaking the task
Refer to SWP “General work in room 214” for general instructions on safe work in the room 214, and to “SWP General Use of
electrical equipment” for instructions on safe use of electrical equipment.
1.
Inspect the pH meter, ensure that the electrical cord is in good condition and that the equipment has been electrically tested
the previous year. Before using the equipment read the instruction manual.
NOTE: If you need to pH with 10M HCL, as opposed to 0.1M HCL, you must carry out this process in the fume cupboard, located
in Rm WW 215. Please read the SWP on the fume hood before use.
2.
3.
Turn the pH meter on at the power point, and turn the unit on (switch is at back)
Firstly the pH meter needs to be calibrated
NOTE: A “*” in place of the decimal point indicates that the pH readout is not calibrated (full 2-point calibration), or a past
calibration has failed.
4.
5.
Press the ‘Mode” button until pH mode is selected. Rinse the pH probe in distilled water and blot dry.
Place the probe into a small sample of primary buffer (pH 6.88 or pH 7.00) so that the bulb and reference junction are both
covered.
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NOTE: DO NOT place the probe directly into the primary buffer bottle as this will contaminate the buffer and reduce its lifespan.
The samples of primary buffer should be changed when the colour of the solution begins to change.
6.
7.
Press the ‘Calibrate’ button to calibrate. The Display will now show an ‘X’ on the screen, along with the message ‘wait’, once
the reading has stabilised the unit will calibrate itself.
Rinse the probe in distilled water and blot dry on a clean kim-wipe. Place the probe into a sample of the secondary buffer (
pH4.0, 9.23, or 10.01). Repeat Step 6.
NOTE: the ‘*’ in the pH reading will now be replaced by a decimal point if calibration was successful.
8.
9.
To measure the pH of a solution, ensure that the meter is in pH mode (see Step 4).
Rinse the probe in distilled water and blot dry. Place the probe in the solution to be tested and wait for the reading to stabilise.
NOTE: To adjust the pH of a solution carefully add (dropwise) either 0.01M NaOH (increases pH of solution) or 0.01M HCl
(decreases pH of solution). This should be preformed while gently stirring the solution (magnetic stirrer) to ensuring proper mixing
of the NaOH or HCl.
10. .After recording the reading rinses the probe and blot dry. Store the probe in a saturated KCl solution.
11. Turn off the pH when not in use.
6.List emergency shutdown procedures
In the event of an electrical emergency either turn the pH meter off at the unit/power point or hit the “Laboratory Power Emergency
Shutdown” button.
Please notify the Laboratory Manager of any incidents
7.List Emergency procedures for how to deal with fires, spills or exposure to hazardous substances
Potential Hazards and exposure to chemicals by the skin, eyes, inhalation and ingestion. To lower this risk, all staff and students are
required to wear full PPE when working in the laboratory. To limit the risk of inhaling the fumes of 10M HCl or NaOH, all staff/students
are required to use these solutions in the fume cupboard. Prior to working with any chemical reagent/s, staff/students are also required
to read the appropriate MSDS’s.
All staff and students are trained to use the pH meter and have also been orientated in the chemical hazards that exist in the
Laboratory.
Chemical Lists and MSDS are located in the Laboratory as a risk management procedure.
Laboratory induction and regular OHS discussions at Lab Meetings reinforce the potential hazards
8.List Clean up and waste disposal requirements
Make sure the pH meter is turned off after use.
Ensure that the pH probe is placed in the saturated KCL solution. If this solution if running low, please refill the tube from the stock KCl
bottle (there MUST be enough to cover the pH bulb and the reference junction). If the KCl stock bottle is empty, it is YOUR
responsibility to make some more up.
9.List legislation used in the development of this SWP
NSW OHS Act 2000
NSW OHS Regulation 2001
Australia Dangerous Goods Code
Code of Practice for the Labelling of Workplace Substances
AS/NZS 2243.2:2006. Safety in laboratories. Part 2: Chemical aspects
Australian Standard AS2243.6-1990. Safety in laboratories. Part 6: Mechanical Aspects.
Australian Standard AS2243.7-1991. Safety in laboratories. Part 7: Electrical Aspects.
AS/NZS 2161.1:2000 Occupational Protective Gloves – Selection, Use and Maintenance
Safe Work Procedure Form (OHS026)
UNSW Hazardous Waste Disposal Procedure
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10a.List competency required – qualifications, certificates, licensing, training - e.g. course or instruction:
Induction in the lab 214. OHS awareness, laboratory safety awareness and hazardous substances training.
10b. List competency of Assessor
11.Supervisory approval, And review
Supervisor:
Prof. Margaret J. Morris
Responsibility for SWP review:
Signature:
Date of review:
12.SWP Sign off sheet
SWP name and version:
In signing this section the assessor/ authorisor agrees that the following persons are competent in following this
SWP
Name
Signature
Date
Competent
Name of Assessor/Authoriser
Assessor/Authoriser
signature
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