Metrology and Quality Assurance
Open Ended Lab
Group Members:
Junaid Ehsan
(2019-ME-402)
Husnain Raza
(2019-ME-404)
Rafay Mehmood
(2019-ME-411)
Umar Ashfaq
(2019-ME-414)
Amir Pervaiz
(2019-ME-418)
Hassan Mukhtar
(2019-ME-428)
Safi Ullah
(2019-ME-429)
Asjad Waseem Mirza
(2019-ME-437)
Syed Rehman Jamil
(2019-ME-443)
Submitted To:
Engineer Mohsin Ahmad Sadiq
Rachna College of Engineering and Technology, Gujranwala
Contents:
Theoretical Background: ................................................................................................................. 1
Equipment: ...................................................................................................................................... 2
Operation: ....................................................................................................................................... 3
Specification: ................................................................................................................................... 3
Experiment # 01: ............................................................................................................................. 4
To calibrate the Ph meter via the use of buffer powder ........................................................ 4
Experiment # 02: ............................................................................................................................. 5
To find the pH of different water solution with impurities by the use of pen type pH Meter.
................................................................................................................................................. 5
Experiment # 03: ............................................................................................................................. 6
To check the pH of different samples by the use of pen type pH meter. .............................. 6
i
Theoretical Background:
What is pH?
pH is a measure of how acidic/basic solution is. The range goes from 0 - 14, with 7 being neutral.
pH of less than 7 indicate acidity, whereas a pH of greater than 7 indicates a base. pH is really a
measure of the relative amount of free hydrogen and hydroxyl ions in the solution.
pH meter:
A pH meter is an instrument used to measure hydrogen ion activity in solutions. In other words,
this instrument measures acidity/alkalinity of a solution. The degree of hydrogen ion activity is
ultimately expressed as pH level, which generally ranges from 1 to 14.
Types of pH meter:
The most useful way to categories pH meters is into three main group or types.
•
Pen type pH meter
•
Handheld/portable meters
•
Benchtop meters
To help you narrow-down your selection process this article will delve into the three types of pH
meters, giving product examples and suggested applications for each type.
Handheld/portable meters:
Instruments used to measure the acidity or alkalinity of a sample, and designed for portability and
durability. Portable pH meters are most often used away from the physical lab to measure the
acidity or alkalinity of liquids in more remote locations.
Portable pH meter
1
Benchtop pH Meter:
A benchtop pH meter is an electronic instrument used to measure the acidity and alkalinity of
liquid or semi-solid samples across many industries with applications in waste water, drinking
water, food and beverage, chemical and pharmaceutical testing.
Benchtop pH meter
Buffer Powder:
pH Buffer Solution Powder should be used to help keep your electronic pH meter calibrated.
Individually packaged helps to keep the solution fresh until use.
Buffer Powder
Equipment:
Pen type pH meter:
A high accuracy pen-type pH meter designed to test pH level of liquids in various industries and
applications such as Hydroponics, Aquariums, Swimming Pools, Spas and Food processing and
many others. pH level varies with temperature and affects the accuracy of reading results even the
slightest change in temperature.
2
Operation:
•
Remove the protective cap.
•
Do not be alarmed if white crystals appear around the cap.
•
This is normal with pH electrodes and they dissolve when rinsed with water.
•
Tum the meter on sliding the switch on the top.
•
Immerse into solution up to the max immersion level. Stir gently and wait until the display
stabilizes.
•
After use, switch off pH meter, use the water clean the electrode and replace the protective cap.
•
Do not use distilled OR deionized water for storage purpose.
•
Large fluctuations in readings could be due to lack of calibration, dry electrode or rundown
batteries.
Specification:
Range
0.0 to 14.0 pH
Resolution
0.1 pH
Accuracy
±0.1 pH (at20°C) ±0.2 pH
Calibration
manual, 1 point
Environment
RH 95% max;0 to 50°C (32 to 122°F)
Batteries
3 x 1.5V alkaline
Life
Approx. 150 hours of use
Dimension
152x30x21mm (5.9x1.2x0.8")
Weight
50g
3
Experiment # 1
Objective:
To calibrate the Ph meter via the use of buffer powder
Apparatus:
Pen type pH meter, buffer powder of pH 6.86, Distilled water, Beaker
Theory:
Calibration:
Calibration is the process of configuring an instrument to provide a result for a sample within an
acceptable range. Eliminating or minimizing factors that cause inaccurate measurements is a
fundamental aspect of instrumentation design.
Why we do calibration:
The primary significance of calibration is that it maintains accuracy, standardization and
repeatability in measurements, assuring reliable benchmarks and results. Without regular
calibration, equipment can fall out of spec, provide inaccurate measurements and threaten quality,
safety and equipment longevity.
Procedure:
•
Remove the protective cap of pen type pH meter.
•
Dissolve the buffer powder of 6.86 pH in 200ml of distilled water.
•
Immerse the tester up to the maximum immersion level in pH 6.86 buffer solution.
•
Allow the reading to stabilize and using the small screwdriver adjust the calibration timer to read
6.9
Observations:
Sample
pH
Buffer powder (6.86)
6.9
Buffer powder (4.00)
4.0
4
Experiment # 2
Objective:
To find the pH of different water solution with impurities by the use of pen type pH Meter.
Apparatus:
Pen type pH meter, Beaker, distilled water, stirrer, Thermometer,
Impurities:
Lemon, Vinegar, Soap
Theory:
Impurity


A constituent which impairs the purity of something.
Aluminum and Lead are impurities frequently found in tap water.
Procedure:
•
Remove the protective cap.
•
Do not be alarmed if white crystals appear around the cap.
•
This is normal with pH electrodes and they dissolve when rinsed with water.
•
Tum the meter on sliding the switch on the top.
•
Immerse into solution up to the max immersion level.
•
Stir gently and wait until the display stabilizes.
•
After use, switch off pH meter, use the water clean the electrode and replace the protective cap.
Observations:
Sr #
Test sample of 100ml
ph
1
Tap water
7.8
2
Bottle water
7.6
3
Dispenser water
7.8
5
Experiment # 3
Objective:
To check the pH of different samples by the use of pen type pH meter.
Apparatus:
Pen type pH meter, Beaker, distilled water, stirrer, Thermometer.
Vinegar
Vinegar is an aqueous solution of acetic acid and trace compounds that may include
flavorings. Vinegar typically contains 5–8% acetic acid by volume.
Procedure:
•
Remove the protective cap
•
Turn the meter ON sliding the switch on the top
•
Immerse into solution up to the max immersion level
•
Stir gently and wait until the display stabilizes.
•
After use, switch off pH meter, use the water clean the electrode and replace the protective cap.
•
Large fluctuations in readings could be due to lack of calibration, dry electrode or rundown
batteries.
Observations:
Sr #.
Impurity in 100ml water
pH value
1
15 drops vinegar
3.6
2
15 drops lemon juice
3.4
3
One bottle cap bonus detergent
10.6
6