For precise pH analysis, state-of-the-art equipment is indispensable. Our advanced instrumentation includes pH meters and electrodes, ensuring accurate and reliable measurements across diverse samples. With intuitive interfaces and high sensitivity, our equipment empowers researchers and industry professionals to assess acidity and alkalinity levels with confidence, facilitating optimal decision-making and quality assurance in various applications.

1. Build World Class Food factories
PMG Engineering Private Limited
The End-to-End Engineering Company in Food Industry
info@pmg.engineering | www.pmg.engineering
Builds World Class Food factories
Equipment Used for pH Analysis
A Comprehensive Guide to pH Measurement Techniques and
Equipment

2. Build World Class Food factories
PMG Engineering Private Limited
The End-to-End Engineering Company in Food Industry
info@pmg.engineering | www.pmg.engineering
Competent People. Smarter Work Systems. Exceptional Customer Interactions.
Index
1. Introduction
2. pH Measurement Techniques
3. Electrochemical Equipment
4. pH Meters
5. pH Electrodes
6. Optical Methods
7. Absorption Spectroscopy for pH Analysis
8. Fluorescence Spectroscopy for pH Analysis
9. pH Paper and Test Strips
10. Conclusion
11. Reference
2

3. Build World Class Food factories
PMG Engineering Private Limited
The End-to-End Engineering Company in Food Industry
info@pmg.engineering | www.pmg.engineering
Competent People. Smarter Work Systems. Exceptional Customer Interactions.
1. Introduction
Definition of pH: pH is a measure of the acidity or alkalinity
of a solution, expressed on a scale from 0 to 14. A pH of 7
indicates a neutral solution, while values below 7 indicate
acidic solutions and values above 7 indicate alkaline
solutions.
Importance of pH measurement: pH is a critical
parameter in various fields, such as water treatment,
environmental monitoring, food and beverage,
pharmaceuticals, and agriculture.
Applications of pH analysis: pH measurement is essential for
maintaining water quality, soil fertility, controlling chemical
reactions, monitoring fermentation processes, and ensuring
product safety and compliance with regulations.
3

4. Build World Class Food factories
PMG Engineering Private Limited
The End-to-End Engineering Company in Food Industry
info@pmg.engineering | www.pmg.engineering
Competent People. Smarter Work Systems. Exceptional Customer Interactions.
2. pH Measurement Techniques
Electrochemical
methods:
Potentiometric: measures
the potential difference
between a reference
electrode and a pH-
sensitive electrode.
Amperometric: measures
the current produced by a
redox reaction at a pH-
sensitive electrode.
Optical methods:
Absorption spectroscopy:
measures the absorbance
of light by a pH-sensitive
dye at specific
wavelengths.
Fluorescence
spectroscopy: measures
the fluorescence intensity
of a pH-sensitive probe as
a function of pH.
4

5. Build World Class Food factories
PMG Engineering Private Limited
The End-to-End Engineering Company in Food Industry
info@pmg.engineering | www.pmg.engineering
Competent People. Smarter Work Systems. Exceptional Customer Interactions.
3. Electrochemical Equipment
pH meters:
• Benchtop pH meters: designed for use in
laboratories, offering high accuracy, advanced
features, and a stable platform.
• Portable pH meters: compact and battery-
powered, suitable for field measurements and
on-site testing.
pH electrodes:
• Glass electrodes: consist of a thin glass
membrane sensitive to hydrogen ions, widely
used for their accuracy and versatility.
• ISFET electrodes: ion-sensitive field-effect
transistors, offering a solid-state alternative to
glass electrodes with improved durability.
• Antimony electrodes: metal-based electrodes
with a lower sensitivity to pH but better suited
for specific applications, such as measuring the
pH of highly acidic or alkaline solutions.
5

6. Build World Class Food factories
PMG Engineering Private Limited
The End-to-End Engineering Company in Food Industry
info@pmg.engineering | www.pmg.engineering
Competent People. Smarter Work Systems. Exceptional Customer Interactions.
4. pH Meters
Function and
operation: pH
meters
measure the
potential
difference
between a
reference
electrode and a
pH-sensitive
electrode,
converting the
voltage signal
into a pH value.
Calibration
process:
performed
using buffer
solutions of
known pH
values, typically
at pH 4, 7, and
10, to ensure
accurate
measurements.
Common
features and
specifications:
automatic
temperature
compensation,
multiple-point
calibration,
data storage
and logging,
and user-
friendly
interfaces.
6

7. Build World Class Food factories
PMG Engineering Private Limited
The End-to-End Engineering Company in Food Industry
info@pmg.engineering | www.pmg.engineering
Competent People. Smarter Work Systems. Exceptional Customer Interactions.
5. pH Electrodes
Glass electrodes:
• Structure and operation: consist of a thin glass membrane that selectively responds to hydrogen
ions, generating a potential difference proportional to the pH of the solution.
• Advantages: high accuracy, broad pH range, and compatibility with most samples.
• Disadvantages: fragile, sensitive to temperature changes, and unsuitable for some harsh
environments.
ISFET electrodes:
• Structure and operation: use a semiconductor material sensitive to hydrogen ions, offering a
solid-state alternative to glass electrodes.
• Advantages: robust, resistant to temperature changes, and suitable for harsh environments.
• Disadvantages: limited pH range, potential drift, and higher cost.
Antimony electrodes:
• Structure and operation: consist of an antimony wire that generates a potential difference
proportional to the pH of the solution.
• Advantages: suitable for highly acidic or alkaline solutions and resistant to harsh chemicals.
• Disadvantages: limited pH range, potential drift, and interference from other ions.
7

8. Build World Class Food factories
PMG Engineering Private Limited
The End-to-End Engineering Company in Food Industry
info@pmg.engineering | www.pmg.engineering
Competent People. Smarter Work Systems. Exceptional Customer Interactions.
6. Optical Methods
Absorption spectroscopy:
Principle and operation: measures the absorbance of light by a pH-sensitive dye at specific
wavelengths, with the absorbance being proportional to the pH of the solution.
Equipment: spectrophotometers.
Fluorescence spectroscopy:
Principle and operation: measures the fluorescence intensity of a pH-sensitive probe as a
function of pH, with changes in intensity indicating the pH of the solution.
Equipment: fluorometers.
8

9. Build World Class Food factories
PMG Engineering Private Limited
The End-to-End Engineering Company in Food Industry
info@pmg.engineering | www.pmg.engineering
Competent People. Smarter Work Systems. Exceptional Customer Interactions.
7. Absorption Spectroscopy for pH Analysis
pH indicators:
Commonly used indicators
and their pH ranges:
bromothymol blue (6.0-7.6),
phenol red (6.4-8.0), and
phenolphthalein (8.2-10.0).
Indicator selection criteria:
choose an indicator with a
transition range that includes
the pH value of interest and
is compatible with the
sample matrix.
Spectrophotometer
operation:
Sample preparation: dissolve
the pH indicator in the
sample or prepare a separate
indicator solution for mixing
with the sample.
Calibration process: prepare
a series of standard solutions
with known pH values,
measure their absorbance,
and plot a calibration curve
for determining the pH of the
unknown sample.
9

10. Build World Class Food factories
PMG Engineering Private Limited
The End-to-End Engineering Company in Food Industry
info@pmg.engineering | www.pmg.engineering
Competent People. Smarter Work Systems. Exceptional Customer Interactions.
8. Fluorescence Spectroscopy for pH Analysis
Fluorescent pH
probes:
Commonly used probes and
their pH ranges: fluorescein
(5.9-8.0), SNARF-1 (7.5-8.5),
and seminaphthorhodafluor
(SNARF) dyes.
Probe selection criteria:
choose a probe with a pH-
sensitive fluorescence range
that covers the pH value of
interest and is compatible
with the sample matrix.
Fluorometer
operation:
Sample preparation: dissolve
the fluorescent pH probe in
the sample or prepare a
separate probe solution for
mixing with the sample.
Calibration process: prepare a
series of standard solutions
with known pH values,
measure their fluorescence
intensity, and plot a
calibration curve for
determining the pH of the
unknown sample.
10

11. Build World Class Food factories
PMG Engineering Private Limited
The End-to-End Engineering Company in Food Industry
info@pmg.engineering | www.pmg.engineering
Competent People. Smarter Work Systems. Exceptional Customer Interactions.
9. pH Paper and Test Strips
Overview and function:
pH paper and test strips
are coated with pH-
sensitive dyes that
change color in
response to the pH of a
solution, providing a
quick and simple
method for pH
estimation.
Advantages: cost-
effective, easy to use,
and suitable for field
measurements.
Disadvantages: limited
accuracy, sensitivity to
humidity, and potential
interference from
coloured or turbid
samples.
Application areas: rapid
screening, educational
purposes, and basic
monitoring of water
quality or industrial
processes.
11

12. Build World Class Food factories
PMG Engineering Private Limited
The End-to-End Engineering Company in Food Industry
info@pmg.engineering | www.pmg.engineering
Competent People. Smarter Work Systems. Exceptional Customer Interactions.
10. Conclusion
Importance of accurate pH analysis: maintaining optimal conditions for biological
and chemical processes, ensuring product quality and safety, and complying with
environmental regulations.
Selecting the appropriate equipment for specific applications: consider factors
such as accuracy requirements, sample matrix, environmental conditions, and
budget constraints.
Regular maintenance and calibration: essential for reliable and consistent pH
measurements, helping to prevent errors and improve the accuracy of results.
12

13. Build World Class Food factories
PMG Engineering Private Limited
The End-to-End Engineering Company in Food Industry
info@pmg.engineering | www.pmg.engineering
Competent People. Smarter Work Systems. Exceptional Customer Interactions.
11. Reference
• Harris, D. C. (2015). Quantitative chemical analysis (9th ed.). W.H. Freeman and
Company. https://www.macmillanlearning.com/college/us/product/Quantitative-
Chemical-Analysis/p/131915414X
• Skoog, D. A., West, D. M., Holler, F. J., & Crouch, S. R. (2018). Fundamentals of analytical
chemistry (9th ed.). Brooks Cole. https://www.cengage.com/c/fundamentals-of-
analytical-chemistry-9e-skoog/9780495558286
• Hanna Instruments. (n.d.). pH measurement guide. Retrieved from
https://hannainst.com/usa/pub/products/pH_measurement_guide.pdf
• Thermo Fisher Scientific. (n.d.). A guide to pH measurement. Retrieved from
https://www.thermofisher.com/document-connect/document-
connect.html?url=https%3A%2F%2Fassets.thermofisher.com%2FTFS-
Assets%2FCAD%2FReference-Materials%2FpH-guide-booklet.pdf
• Horiba. (n.d.). A guide to pH measurement – theory and practice. Retrieved from
https://www.horiba.com/fileadmin/uploads/Scientific/Documents/FLS/LAQUA_pH_The
ory_Practice_WEB.pdf
13

14. Build World Class Food factories
PMG Engineering Private Limited
The End-to-End Engineering Company in Food Industry
info@pmg.engineering | www.pmg.engineering
Competent People. Smarter Work Systems. Exceptional Customer Interactions.
#
We deliver End-to-End Engineering Design and Construction Management
Projects in Food and Beverage Industry.
Meeting Global Benchmarks
In ENGINEERING DESIGN and PROJECT MANAGEMENT
for FOOD and BEVERAGE Industry with SINGLE POINT ACCOUNTABILITY
Process Engineering | Project Management | Mechanical | Electrical | Automation | Food Safety
Key Clients
We deliver End-to-End Engineering Design and Construction Management
Projects in Food and Beverage Industry.
Meeting Global Benchmarks
In ENGINEERING DESIGN and PROJECT MANAGEMENT
for FOOD and BEVERAGE Industry with SINGLE POINT ACCOUNTABILITY
Process Engineering | Project Management | Mechanical | Electrical | Automation | Food Safety
Key Clients
We deliver End-to-End Engineering Design and Construction Management
Projects in Food and Beverage Industry.
Meeting Global Benchmarks
In ENGINEERING DESIGN and PROJECT MANAGEMENT
for FOOD and BEVERAGE Industry with SINGLE POINT ACCOUNTABILITY
Process Engineering | Project Management | Mechanical | Electrical | Automation | Food Safety
Key Clients
Our Clients