Nephlometry and turbidometry in PHARMACEUTICAL ANALYSIS – I

1. Nephlometry and
Turbidometry
Presented by
Patan Basha
B – Pharm ( Pharmacist )
1

2. Contents
 Introduction
 Principle
 Choice of Method
 Factors Responsible for producing uniform Turbidity
 Factors Responsible for Intensity of Scattered Radiation
 Effect of Concentration and Wavelength on scattering
 Instrumentation
 Applications
2

3. Introduction
 Nephlometry and Turbidometry methods depend on the scattering of light by particles
suspended in a liquid.
 The suspended particles have refractive index different from that of the medium.
 Nephlometry is measurement of scattered light as a function of concentration of
suspended particles (less than, approximately 100mg/litre)
 Turbidometry is measurement of transmitted light as a function of concentration of
suspended particles (more than, 100mg/litre)
3

4. Principle
 Nephlometry: At low concentration of a suspension there is
uniform scattering of particle. Hence the intensity of scattered
light is directly proportion to the concentration.
 The intensity of scattered light is normally measured at 90o
 Turbidimetry: At high concentration of a suspension scattering
is not uniform and light is scattered in all direction. Hence the
intensity of transmitted light is measured at 180o
4

5. Choice of Method
 Nephlometry and Turbidometry depends on the concentration of
suspension
 The Concentration of suspension is less, scattering of light is less and
can be accurately measured at 90o.
 This makes Nephlometry as the choice in low concentrated suspension.
 The Concentration of suspension is more, scattering is also more.
 Only transmitted light can be measured at 180o.
 This makes Turbidometry as the choice in high concentrated suspension
5

6. Factors Responsible for producing uniform
Turbidity
Uniform turbidity of suspension
 Manner, order and rate of mixing
 Agitation of suspension
 Temp. affects solubility of substance and viscosity of medium.
 Presence and absence of inert electrolyte
 Conc. Of solution mixed to get a suspension
6

7. Factors Responsible for Intensity of Scattered
Radiation
 No of suspended particle (Con.c)
 Size and shape of particle (= or greater than wavelength of light)
 Wavelength of radiation not to absorp. Only scattering
 Different ref.index of particles and medium
7

8. Effect of Concentration and Wavelength on
scattering
 Concentration
The intensity of transmitted light is expressed using an equation
P =Power of transmitted light
Po = power of incident beam
T = Turbidity co-efficient
B = Path length
 Wavelength
It is expressed by the following equation
T = Turbidity, S = Constant for a given system
 = Wavelength. t = size of particle
8

9. Instrumentation
 Source of Light
 Tungsten Lamp & Mercury arc
 Filter and Monochromators
 Tubidimeter blue filter or 530 nm is used
 Sample cells
 Detectors
 Photovoltaic cell
 Photo tube
 Photomultiplier
9

10. Nephlometer
10

11. Turbidimeter
11

12. Nephloturbidimeter
12

13. Applications
 Analysis of water
Adding selective precipitants (Cl ions add AgNO3 gives AGCl ppt)
 Determination of Carbondioxide
 CO2 + Barium salt gives Barium carbonate
 Determination of Inorganic substances
 Phosphorus –Strychnine Molybedate
 Ammonia- Nesslers reagent
 SO4- Barium chloride give Barium sulphate
 Flouride- Calcium flouride
 CN- AGCN
 Ca++ give CaOxalate
 Zn- Zinc Ferrocyanide
13

14. Applications
 Quantitative analysis of ions
 Miscellaneous
 Water treatment plant, sewage work, breweries, bottling industry,
petroleum refineries
 Turbidimetric titrations
14

15. 15

16. 16

17. Thank you...💕💕