nephalo and turbidimetry
DESCRIPTION
analysisTRANSCRIPT
![Page 1: Nephalo and turbidimetry](https://reader030.vdocuments.us/reader030/viewer/2022012321/5476c453b4af9fed5f8b46c4/html5/thumbnails/1.jpg)
NEPHELOMETRY AND
TURBIDIMETRY
![Page 2: Nephalo and turbidimetry](https://reader030.vdocuments.us/reader030/viewer/2022012321/5476c453b4af9fed5f8b46c4/html5/thumbnails/2.jpg)
T.B.EKNATH BABU[T.B.E.K.B]
STUDENT AT ARULMIGU KALASALINGAM
COLLEGE OF PHARMACY
![Page 3: Nephalo and turbidimetry](https://reader030.vdocuments.us/reader030/viewer/2022012321/5476c453b4af9fed5f8b46c4/html5/thumbnails/3.jpg)
INTRODUCTION When electromagnetic radiation (light) strikes
a particle in solution, some of the light will be absorbed by the particle, some will be transmitted through the solution and some of the light will be scattered or reflected.
The amount of light scattered is proportional to the concentration of insoluble particle. We will focus on the concept of light scatter
![Page 4: Nephalo and turbidimetry](https://reader030.vdocuments.us/reader030/viewer/2022012321/5476c453b4af9fed5f8b46c4/html5/thumbnails/4.jpg)
THEORY Scattered light may be measured by Turbidimetry Nephelometry In turbidimetry, the intensity of light
transmitted through the medium, the unscattered light, is measured.
![Page 5: Nephalo and turbidimetry](https://reader030.vdocuments.us/reader030/viewer/2022012321/5476c453b4af9fed5f8b46c4/html5/thumbnails/5.jpg)
Turbidometric measurements are made at 180o from the incident light beam.
In Nephelometry, the intensity of the scattered light is measured, usually, but not necessarily, at right angles to the incident light beam.
![Page 6: Nephalo and turbidimetry](https://reader030.vdocuments.us/reader030/viewer/2022012321/5476c453b4af9fed5f8b46c4/html5/thumbnails/6.jpg)
The two techniques differs only in the manner of measuring the scattered radiation.
![Page 7: Nephalo and turbidimetry](https://reader030.vdocuments.us/reader030/viewer/2022012321/5476c453b4af9fed5f8b46c4/html5/thumbnails/7.jpg)
Turbidity can be measured on most routine analysers by a spectrophotometer (absorbed light)
Reduced sensitivity and precision. Extent of light scattering increases as
wavelength increases The intensity of scattered light is normally
measured by Nephelometer.
![Page 8: Nephalo and turbidimetry](https://reader030.vdocuments.us/reader030/viewer/2022012321/5476c453b4af9fed5f8b46c4/html5/thumbnails/8.jpg)
Light scattering is the physical phenomenon resulting from the interaction of light with a particles in solution.
Dependent on : Particle size Wavelength Distance of observation, Concentration of particles MW of particles
![Page 9: Nephalo and turbidimetry](https://reader030.vdocuments.us/reader030/viewer/2022012321/5476c453b4af9fed5f8b46c4/html5/thumbnails/9.jpg)
TYNDALL EFFECT Scattering of light- by particles in a colloid or
suspension. the longer-wavelength light is more
transmitted while the shorter-wavelength light is more reflected via scattering.
![Page 10: Nephalo and turbidimetry](https://reader030.vdocuments.us/reader030/viewer/2022012321/5476c453b4af9fed5f8b46c4/html5/thumbnails/10.jpg)
LIGHT SCATTERING PHENOMENON
The blue color of the sky and the red color of the sun at sunset result from scattering of light of small dust particles, H2O molecules and other gases in the atmosphere.
The efficiency with which light is scattered depends on its wavelength, λ. The sky is blue because violet and blue light are scattered to a greater extent than other longer wavelengths.
![Page 11: Nephalo and turbidimetry](https://reader030.vdocuments.us/reader030/viewer/2022012321/5476c453b4af9fed5f8b46c4/html5/thumbnails/11.jpg)
NEPHELOMETRY ↓ concentration, uniform scattering, intensity
of scatted light proportional to conc. measured at 900
TURBIDIMETRY ↑ concentration, scattering not uniform,
intensity of transmitted light measured at 1800
![Page 12: Nephalo and turbidimetry](https://reader030.vdocuments.us/reader030/viewer/2022012321/5476c453b4af9fed5f8b46c4/html5/thumbnails/12.jpg)
Turbidimetry↨
Colorimetry Measurement of the intensity of light transmitted
through a medium, light intensity is decreased.Nephelometry
↨Fluorimetry
Measurement of scattered light at 900
![Page 13: Nephalo and turbidimetry](https://reader030.vdocuments.us/reader030/viewer/2022012321/5476c453b4af9fed5f8b46c4/html5/thumbnails/13.jpg)
COLORIMETERSimilarity: transmitted light measured measured at 1800
TURBIDIMETERSimilarity:transmitted light measured measured at 1800
Difference: Absorption of radiation
Difference: Scattering of radiation
![Page 14: Nephalo and turbidimetry](https://reader030.vdocuments.us/reader030/viewer/2022012321/5476c453b4af9fed5f8b46c4/html5/thumbnails/14.jpg)
FLOURIMETRYSimilarity: Emergent radiation measured at 900
Difference:» emitted radiation measured» emitted radiation – longer WL than incident light
NEPHELOMETRYSimilarity: Emergent radiation measured at 900
Difference:» Scattered radiation measured» emitted radiation – same WL as that of incident light
![Page 15: Nephalo and turbidimetry](https://reader030.vdocuments.us/reader030/viewer/2022012321/5476c453b4af9fed5f8b46c4/html5/thumbnails/15.jpg)
CHOICE OF THE METHOD depends upon the amount of light scattered by
suspended particles present in solution.
TURBIDIMETRY - high concentrated suspensions
NEPHELOMETRY - low concentrated suspensions
- more accurate results
![Page 16: Nephalo and turbidimetry](https://reader030.vdocuments.us/reader030/viewer/2022012321/5476c453b4af9fed5f8b46c4/html5/thumbnails/16.jpg)
INSTRUMENTATION The basic instrument contains Light Source:Tungsten lamp, White light - nephelometers Filters - Turbidimeter (blue filter or 530 nm) Nephelometer (visible filter) Sample cells Detectors (photometric)
![Page 17: Nephalo and turbidimetry](https://reader030.vdocuments.us/reader030/viewer/2022012321/5476c453b4af9fed5f8b46c4/html5/thumbnails/17.jpg)
CELLS cylindrical cells - flat faces to minimize
reflections & multiple scatterings
![Page 18: Nephalo and turbidimetry](https://reader030.vdocuments.us/reader030/viewer/2022012321/5476c453b4af9fed5f8b46c4/html5/thumbnails/18.jpg)
FACTORS AFFECTING MEASUREMENTS
The amount of radiation removed or deviated from the primary radiation beam depends on the following factors
1.Concentration Turbidimetry: S = log I/Io= kbc T=Transmittance = I/Io S = turbidence due to scattering k = turbidity constant b= path length c = concentration of suspended material
![Page 19: Nephalo and turbidimetry](https://reader030.vdocuments.us/reader030/viewer/2022012321/5476c453b4af9fed5f8b46c4/html5/thumbnails/19.jpg)
Nephelometry: Is = Ks Io C Is = scattered intensity Ks= empirical constant Io = Incident intensity c = concentration of suspended material
![Page 20: Nephalo and turbidimetry](https://reader030.vdocuments.us/reader030/viewer/2022012321/5476c453b4af9fed5f8b46c4/html5/thumbnails/20.jpg)
2. Effect of Particle Size on Scattering Size and the shape of the particles responsible
for the scattering. Because most analytical applications involve
the generation of a colloidally dispersed phase in a solution, those variables that influence particle size during precipitation also affect both turbidimetric and nephelometric measurements.
![Page 21: Nephalo and turbidimetry](https://reader030.vdocuments.us/reader030/viewer/2022012321/5476c453b4af9fed5f8b46c4/html5/thumbnails/21.jpg)
Turbidimetry-Practical Considerations
Selecting λ: Important. It is necessary to avoid radiation that is absorbed by the sample.
Sample Preparation Scattering is related to: 1.Concentration of the scattering particles 2.Particle size 3.Particle shape
![Page 22: Nephalo and turbidimetry](https://reader030.vdocuments.us/reader030/viewer/2022012321/5476c453b4af9fed5f8b46c4/html5/thumbnails/22.jpg)
APPLICATIONS
1. Analysis of water clarity, conc. of ions2. Determination of CO2
3. Determination of inorganic substances Sulphate – barium chloride Ammonia – Nesslers reagent Phosphorus – Strychine molybedate4. Biochemical Analysis5. Quantitative Analysis – (ppm level)
![Page 23: Nephalo and turbidimetry](https://reader030.vdocuments.us/reader030/viewer/2022012321/5476c453b4af9fed5f8b46c4/html5/thumbnails/23.jpg)
6. Miscellaneous Water treatment plants, sewage work, refineries,
paper industry7. Atmospheric pollution smokes & fogs8. Determination of mole. Wt of high polymers9. Phase titration
NEPHLOTURBIDIMETER Two detectors
![Page 24: Nephalo and turbidimetry](https://reader030.vdocuments.us/reader030/viewer/2022012321/5476c453b4af9fed5f8b46c4/html5/thumbnails/24.jpg)