Principle of Turbidity in pharma
Turbidity is the optical property, that causes light to be scattered and absorbed, rather than transmitted. The scattering of the light that passes through a liquid is primarily caused by the suspended solids. The higher the turbidity, the greater the amount of scattered light. The light beam that passes through the sample is scattered in all directions. The intensity and pattern of the scattered light are affected by many variables like the wavelength of the incident light, particle size and shape, refractive index, and color.
The measurement unit of the turbidity is NTU ( Nephelometric Turbidity Unit). Another unit is EBC (European Brewery Committee) or Nephelos
Turbidity testing equipment is known as the Turbidity meter.
What are the turbidity measurement methods?
There are two types of turbidity measurement methods, you can measure turbidity with an electronic turbidity meter or with a
turbidity tube. Depending on the method used to measure turbidity, the measurement is usually expressed in nephelometric turbidity units (NTU) or Jackson turbidity units (JTLJ).
What is a turbidity conversion chart?
Convert cm measurements to Nephelometric Turbidity Units (NTUs) by using the Turbidity Conversion Chart. This is the official unit of measurement used to quantify the amount of light scattered by the suspended sediments. By using the turbidity conversion chart below, possible to convert turbidity tube reading from a height to NTUs.
| Distance from bottom of the tube (cm) | NTU’s |
| <6.25 | >240 |
| 6.25 to 7 | 240 |
| 7 to 8 | 185 |
| 8 to 9.5 | 150 |
| 9.5 to 10.5 | 120 |
| 10.5 to 12 | 100 |
| 12 to 13.75 | 90 |
| 13.75 to 16.25 | 65 |
| 16.25 to 18.75 | 60 |
| 18.75 to 21.25 | 40 |
| 21.25 to 23.75 | 35 |
| 23.75 to 26.25 | 30 |
| 26.25 to 28.75 | 27 |
| 28.75 to 31.25 | 24 |
| 21.25 to 33.75 | 21 |
| 33.75 to 36.25 | 19 |
| 36.25 to 38.75 | 17 |
| 38.75 to 41.25 | 15 |
| 41.25 to 43.75 | 14 |
| 43.75 to 46.25 | 13 |
| 46.25 to 48.75 | 12 |
| 48.75 to 51.25 | 11 |
| 51.25 to 53.75 | 10 |
| 53.75 to 57.5 | 9 |
| 57.75 to 60 | 8 |
| Over the top | 6 |
| – | – |
This is a principle of turbidity, turbidity measurement chart, and its measurement methods.
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