1. Pesticide Monitoring & Detection.
Low Zhan Hong
Tung Yew Kiong
Peng Chenyu

2. •Scope
Objectives
Abstract:
1
Pesticides; A Source of Pollution
ELISA:
2
Enzyme-Linked Immunosorbent Assay
SPR Immunosensing:
3
Surface Plasmon Resonance Immunosensing
RIFS Direct Immunosensing Reflectometric:
4
Reflectometric Interference Spectroscopy
Advantage & Disadvantage:
5
3 Technologies
Conclusion
6

3. •Abstract
Pesticides; A Source of Pollution
• In agriculture, pesticides
are widely used by
farmers to control
diseases and for
obtaining high yields.
• Pesticide is a term used
in a broader sense for
chemicals, synthetic or
natural, that are used for
the control of insects,
fungi, bacteria, weeds,
rodents and other pests.

4. •Abstract
Pesticides; A Source of Pollution
• Undegraded pesticide
residues may enter into
the food chains through
air, water and soil and
cause several health
problems and disrupt the
ecosystems, birds, animals
and human beings.
• Pesticides can be
carcinogenic or citogenic,
they can produce bone
marrow diseases, infertility,
nerve disorders and
immunological and
respiratory diseases.

5. •Abstract
Pesticides; A Source of Pollution
As large amount of
pesticides are currently
being used, there is an
increased interest for
developing rapid screening
systems for their detection.

6. •Techniques used for Pesticides
• The most commonly • These • In spite of their
used analytical conventional advantages,
methods for methods are these techniques
pesticide analysis sensitive, reliable need expensive
includes high and precise. instrumentation,
pressure liquid require skilled
chromatography, technicians, and
gas chromatography are time
or coupled consuming,
techniques of GC- laborious and not
MS. easily adoptable
for field analysis.

7. •ELISA:
Enzyme-Linked Immunosorbent Assay
• ELISA is a common example of an
immunoassay with the use of an
enzyme tracer.More information can
be added here by changing this text.

8. •ELISA:
Enzyme-Linked Immunosorbent Assay - Steps
• A test tube is then coated with a
known amount of pesticide and
so the pesticide is immobilized
on the surface of the tube.
• The antibody that recognizes
and binds to that pesticide is
then added. Some of the
antibody binds to the
immobilized pesticide.

9. •ELISA:
Enzyme-Linked Immunosorbent Assay - Steps
• The extract is then washed
away, and the amount of
antibody bound to the
immobilized pesticide will next
be measured using the enzyme
tracer.
• A tracer enzyme may be
already attached to the
antibody or may be attached by
adding a second antibody (that
binds to the first) conjugated
with the enzyme. A solution of
colourless substrate is added,
which will be changed by the
enzyme to a coloured product.

10. •ELISA:
Enzyme-Linked Immunosorbent Assay - Steps
• The amount of antibodies bound
to the immobilized pesticide is
shown by intensity of the colour;
the greater the intensity, the less
pesticide is in the sample.
• The intensity of the colour can
be measured through the use of
a micro-spectrophotometer
(transducer), which may be
linked to a computer with data-
analysing software which is then
compared against a standard
curve, derived from the
standards, to give the amount of
pesticide in the sample.

11. •Immunosensors for Pesticides
Introduction.
Immunosensors can be
distinguished from
immnunoassays where
the transducer is not an
integral part of the
analytical system.

12. •Immunosensors for Pesticides
Introduction.
Immunosensors are
biosensors which use
antibodies (Ab) or
antigens (Ag) as the
specific sensing element
and provide
concentration-
dependent signals.

13. •Immunosensors for Pesticides
Introduction.
Basically it consists of two
processes, a molecular
recognition process, for
detecting the specific Ag–Ab
binding reaction at the surface
of receptor, and a signal-transfer
process, for responding to the
changes in an electrochemical,
optical, spectroscopic, or
electrical parameter of the
receptor caused by the specific
binding reaction.

14. • Surface Plasmon Resonance (SPR) Immunosensing
- Steps.
• SPR immunosensing involves immobilizing
Ab (or Ag) through a coupling matrix to
the thin gold surface on the reflecting
surface of a glass prism.
• Interaction between Ag and Ab on the
surface will elicit a change in the
refractive index resulting in variations of
the light intensity.

15. • Surface Plasmon Resonance (SPR) Immunosensing
- Steps.
The detection principle relies on detecting
changes in the refractive index of the
solution close to the surface of the sensor
chip due to shifts in mass occurring after
biomolecule binding.

16. • Surface Plasmon Resonance (SPR) Immunosensing
Monitoring of pesticide chlorpyrifos in water samples using SPR
immunossesnors
Spread the chlorpyrifos
that is transmitted from
the source on the gold
coated sensing surface
of the SPR immunosensor
1
Allow it to stick on the
gold coated sensing
surface to fight with the
free chlorpyrifos which is
binding to the antibody
Thus, it will lead to a rise
with concentrations of 3 2
chlorpyrifos which
decrease the SPR signal

17. •Reflectometric Interference Spectroscopy (RIFS)
- Steps.
RIFS is a direct
immunosensing
reflectometric
technique.
A white incident light
will pass the interface
between the different
refractive indices.

18. •Reflectometric Interference Spectroscopy (RIFS)
- Steps.
The binding of the Ab
(antibody) to the
surface changes the
thickness of the toggling
layer, which causes a
change in the
reflectance spectrum.
Therefore, the
interaction process
between the Ab and
the hapten derivative
on the surface can be
detected time-resolved.

19. •Advantages & Disadvantages
Immunoassays, to chromatography and other detection and
monitoring methods.
ADVANTAGE DISADVANTAGES
• Immunoassays are • Immunoassay may not be as
particularly suited for water- sensitive for some
soluble pesticides that are compounds as conventional
generally difficult to analyse methods.
using conventional analytical • Immunoassay are
methods. compound-specific only,
they are not suitable for multi-
residue analysis.

20. •Advantages & Disadvantages
Immunosensors, to chromatography and other detection and
monitoring methods.
ADVANTAGES DISADVANTAGES
• Very selective and sensitive. • Limited immunosensors are
• Can be carried out for commercially available at
detection and monitoring in present time.
the field. • Biomolecule deactivation or
• Can work with complete leaking and high diffusion
automation and give the resistance of the substrate/
results under a short period of biocomponent are also key
timeframe. factors in the development of
immunosensors that can be
applied to pesticide
detection.

21. •Advantages & Disadvantages
Surface Plasmon Resonance (SPR), to chromatography and other
detection and monitoring methods.
ADVANTAGES DISADVANTAGES
• Multi- purpose as it is very • There can be disturbances
good at miniaturization, due to variations in the
reliable portable refractive index or
instrumentation and temperature.
automation.
SOLUTION
• High efficiency in monitoring
interactions that bind without • Through the use of a control
the help of naming the surface, will ensure
biomolecule. separation of signals similar to
• This portable immunosensor binding events from signals
based on SPR technology due to the differences in
could provide a highly refractive index between the
sensitive detection of sample and running buffer.
pesticide analytes at
nanogram per liter levels.

22. •Conclusion
Immunosensors based on Ab–Ag combination are
strong candidates for the screening of pesticide.
However, more genetically modified sensitive
biocatalysts and highly specific antibodies are
needed for the development of stable and robust
biosensors/immunosensors in the near future
applications.

23. Thank You
Question & Answer.
References:
- Biosensors for pesticides;
Huangxian Ju and Vivek Babu
Kandimalla
- Immunosensors for Pesticides, 2008;