This document discusses analytical methods such as nephelometry and turbidimetry. Nephelometry measures the intensity of scattered light from a sample, while turbidimetry measures the intensity of transmitted light. Both methods can be used to determine concentration and involve instrumentation including a radiation source, monochromators, sample cells, and detectors. Nephelometry and turbidimetry have a variety of applications and allow for qualitative and quantitative analysis of substances. They provide advantages of speed and simplicity but also have disadvantages of cost and fragility.

1. M.pharmacy

2. CONTENTS
 Introduction
 Classification
 Principle
 Instrumentation
 Applications
 Qualitative & Quantitative Analysis
 Advantages & Disadvantages

3. Analytical method;-
Definition
Analytical methods are defined as the set of techniques that allow us to know
qualitatively and / or quantitatively the composition of any material and
identification of the material
There are a wide variety of techniques used for analysis, from
simple titrations to very advanced techniques using highly specialized
instrumentation.

4. Analytical methods ;-
Chemical methods Titrimetric or volumetric methods
Gravimetric methods
Gasometric analysis
Instrumental Analysis Potentiometry
Conductometry
Polarography
Amperometric titrations
Refractometry
polarimetry
Nephelometry & Turbidimetry
Chromatographic paper Chromatography, Thin layer Chromatography
,column Chromatography, Gas Chromatography,High pressure liquid Chromatography
Spectroscopy Ultraviolet –visible spectroscopy ,Flourimetry,Atomic Absorption
spectroscopy ,Infrared spectroscopy,Nuclear magnetic Resonance spectroscopy,Mass spectroscopy

5. Tyndall Effect
The Tyndall Effect is the effect of light scattering in many directions in colloidal dispersion,
while showing no light in a true solution. This effect is used to determine whether a mixture
is a true solution or a colloid. Under the Tyndall effect, the longer-wavelength light is more
transmitted while the shorter-wavelength light is more scattered

6. Nephelometry
principle
measurement of intensity of scattered light (Is) as a function of concentration (C) of
the suspended particles
Is ∝c

7. Instrumentation of Nephelometry

8. Radiation source
Tungsten lamp Mercury arc

9. Monochromators
Entrance slit; defines the incoming polychromatic light into narrow beam
Collimator ; It collimates the radiations from the entrance slit
Prism ; It disperse the radiations with respect to the component wavelength
Exit slit ; It selects a narrow band of dispersed radiation and makes it to fall
on the sample which further detected

10. Sample cells
These are otherwise called cuvettes and their shape and material of construction varies
depending on the instrument ,In nephelometry and turbidimetry methods glass is used
Thickness-1cm
Length - 1-2mm
Shape-cylindrical ,rectangular or special cells with flat bottom

11. Detectors
These are devices which converts the light energy into electrical signals that are
displayed in the readout devices ,photomultiplier tube detectors are mainly used
In the nephelometry
Light photocathode photoelectrons dynodes form 1 to other dynode
readout amplication of 106

12. Turbidimetry
principle
measurement of intensity of the transmitted light (It) as a function of concentration(C) of
the suspended particles in a suspension
It ∝1/C

13. Turbidimetry
Instrumentation
The instrumentation for nephelometry and turbidimetry is similar , only the difference is
with the detectors,here we use the photovoltaic cell and phototubes

14. Detectors
Photovoltaic cell
light selenium electrons photocathode potential difference
generated
intensity of radiation deflection electric current
In galvanometer

15. Phototubes
Light photocathode electrons anode current intensity of
generated radiation

16. Nephelometric Turbidity Units (NTU)
Turbidity is a measure of the cloudiness of water. The higher the turbidity, the harder it is to see through the water. Turbidity
measurements are reported in nephelometric turbidity units (NTU) or Jackson turbidity units (JTU). Different units are used
depending on which method is chosen to measure turbidity. These two units are roughly equivalent .
Drinking Water Standard:
Drinking water should have a turbidity of ≤ 5 NTU
. Reason: • Turbidity becomes visible at approximately
5NTU, and water with any visible turbidity may be rejected in favour of a clearer.

17. Nephelometric Turbidity Units
Formula :
NTU = A x (B+C) / C
A = NTU found in diluted sample
B = volume of dilution water, in milliliters,
C = sample volume taken for dilution, in milliliters

18. Applications
Inorganic Analysis ; sulphate,carbonate,cholride,fluoride,cynaide.
Determination of carbondioxide
Organic Analysis ; clarity of citrus juices, benzene in alcohol.
Biochemical Analysis ; growth of bacterium, determination of proteins.
Air & water pollution ; in air dust and smoke are monitored whereas in water
Turbidity.
Phase Titrations
Determination of molecular weights
Drug Development
Atmospheric Pollution-Smoke and fog
Determination of impurities or particulate matter in pharmaceuticals (injections).

19. Nephelometry &Turbidimetry
Advantages
Very rapid procedure
Simplicity in measurement
They are Accurate
Disadvantages
High cost
Easily damaged
They require high power supply
Turbidimetry is used for higher concentrations
Nephelometry is used for lower concentrations

20. Qualitative analysis is performed to establish composition of natural/synthetic
substances. These tests are performed to indicate whether the substance or compound is
present in the sample or not.
Quantitative analysis refers to analysis in which the amount or concentration of an
substance may be determined and expressed as a numerical value in appropriate units

21. Conclusion
Nephelometry and Turbidimetry are Analytical methods which have wide range applications
from the simple detection of the pollution to determination body constituents hence these play a
vital role not only in the analysis of the compounds but also in the clinical analysis.

23. References
1. Instrumental Methods of Chemicals Analysis – Gurdeep R.chatwal
Sham K. Anand
2. instrumental methods of chemical analysis - B.k sharma
3.Internet sources - www.kau.edu.com
www.britannica.com
www.scribd.com
www.ncbi.nlm.nih.gov
www.chemiwikki.com