Nephelo Turbidometry
- 1. Mr. Nimish Shirish Khandekar Roll no. 45; Final year B. Pharm ADCBP, Ashta Under the guidance of: Ms. Nisha Jagtap Ma’am Assistant Professor ADCBP, Ashta
- 3. Introduction Transmission and diffraction of electromagnetic radiation. Amount of light scattered is directly proportional to the concentration or the density of the insoluble particles → k/as Tyndall Effect Scattering is defined as: The phenomenon where, beams of light when impinges with particulate matter change its direction of propagation from one to multiple planes without changing net radiating power of energy. 3 Nepheloturbidometry
- 4. Introduction CONT.. Scattering Elastic Transmittance of radiation without the change of energy Inelastic Transmittance of radiation with the change of energy 4 Nepheloturbidometry
- 5. Introduction CONT.. Scattering depends on: 1. Number of particulate matter present 2. Dimension of particle 3. Wavelength of light 5 Nepheloturbidometry
- 6. Introduction CONT.. Nephelo-turbidimetric analysis → measures the extent of elastic scattered of light when it comes in contact with particulate matter. Nephelo-turbidimetric analysis and Turbidimetry → measurement of intensity of scattered or unscattered light . Turbidimetry → high concentration suspension Nephelo-turbidimetry → low concentration suspension 6 Nepheloturbidometry
- 7. Turbidity Turbidity is expressed as: T = 1/λ. λn. Io/It Where, λ = Length of dispersion through which light passes Io = Intensity of incident light It = Intensity of transmitted light n = Refractive index of the dispersion medium Turbidity is directly proportional to the concentration of the suspension. 7 Nepheloturbidometry
- 8. nephelometry Nephelometry is expressed as: Is = Ks x Io x C Where, Is = Intensity of scattered radiation Io = Intensity of incident radiation Ks = Constant, depends on the nature of suspended particles C = Concentration of the solution 8 Nepheloturbidometry
- 9. Factors affecting scattering Order and rate of mixing of substance within a solution. Agitation of solution containing particulate matter. Temperature of the solution. (Affect on solubility) Viscosity of Medium Presence or absence of electrolyte or protective colloid. Concentration of solution. Number of particulate matter suspended Wavelength of the radiating beam 9 Nepheloturbidometry
- 10. Introduction CONT.. Turbidimetric analysis → high concentration of particulate matter. Smaller diameter of particles gives symmetric scattering; bigger particle size gives asymmetrical scattering Nephelometry → smaller dimension of particles → scattered light right angle to the incident beam → measurment of intensity of scattering done at 90o Turbidimetry → larger dimension of particles → measurment of intensity of scattering done at 10 Nepheloturbidometry
- 11. Introduction CONT.. Scattering of shorter wavelength > Scattering of longer wavelength Transmittance of longer wavelength > Scattering of shorter wavelength Reflection of shorter wavelength > Reflection of longer wavelength 11 Nepheloturbidometry
- 12. Differenctiate betn Nephelometry Turbidimetry Suspended particles < 100 mg/L Suspended particles > 100 mg/L Intensity of scattered light is measured Intensity of unscattered light is measured Low concentration suspension is used High concentration suspension is used Scattering is uniform Scattering is not uniform Intensity of scattered light → proportional to the concentration Intensity of transmitted light → inversely proportional to the concentration Measured at 90o Measured at 180o Detector: Sensitive Photomultiplier Detector: Photocell 12 Nepheloturbidometry
- 13. principle Nepheloturbidimetry → instrumental technique of analysis → based on the phenomenon of scattering of light by particulate matters present in the solution. Transperent medium → intensity of incident light = intensity of transmitted light Opaque or translucent medium → intensity of incident light > intensity of transmitted light. 13 Nepheloturbidometry
- 14. principle Nepheloturbidimetry → detector at 90o Turbidimetry → detector at 180o 14 Nepheloturbidometry
- 16. principle Turbidimetry → determines difference between two large signals. Nephelometry → determines the difference between two small signals 16 Nepheloturbidometry
- 17. instrumentation 1. Radiation Source 2. Filters and monochromators 3. Sample cell 4. Detectors 5. Read out devices 17 Nepheloturbidometry
- 18. Radiation source Mercury Arc Lamp Tungsten Lamp 18 Nepheloturbidometry
- 19. Filters and monochromators Monochromatic light. As per the feasibility → colorimeter with a blue filter (530nm) is turbidimeter; fluorimeter with a visible secondary filter is a nephelometer. Absorption filters and Interference filters → used in Nepheloturbidimetry. Absorption filters → made up of glass or coated with pigment that absorbs unwanted light. Interference filters → dielectric spacer films → made up of CaF2, MgF2 between two silver films. 19 Nepheloturbidometry
- 20. Sample cell Cuvette or sample cells → made up of transperent glasses. Shape → Cylindrical / Rectangular or Special cells with path length 1cm. Special Cell → Measure light scattering → at 45o, 90o and 135o → employed in nepheloturbidimetric analysis. 20 Nepheloturbidometry
- 21. Detectors For turbidimetric analysis → detector placed at 180o 21 Nepheloturbidometry
- 22. For Nepheloturbidimetry analysis → detector placed at 900 22 Nepheloturbidometry
- 23. Applications Determination of particle size. Determination of average molecular weight. Measuring of atmospheric pollutants. Determination of concentration of solution. Growth of bacterial cell in liquid nutrient medium. Determination of end point of precipitation titration., etc 23 Nepheloturbidometry
- 24. THANK YOU!