Turbidimetry (the name being derived from ''
turbidity
Turbidity is the cloudiness or haziness of a fluid caused by large numbers of individual particles that are generally invisible to the naked eye, similar to smoke in air. The measurement of turbidity is a key test of both water clarity and wa ...
'') is the process of measuring the loss of intensity of transmitted
light
Light, visible light, or visible radiation is electromagnetic radiation that can be visual perception, perceived by the human eye. Visible light spans the visible spectrum and is usually defined as having wavelengths in the range of 400– ...
due to the
scattering
In physics, scattering is a wide range of physical processes where moving particles or radiation of some form, such as light or sound, are forced to deviate from a straight trajectory by localized non-uniformities (including particles and radiat ...
effect of particles suspended in it. Light is passed through a filter creating a light of known
wavelength
In physics and mathematics, wavelength or spatial period of a wave or periodic function is the distance over which the wave's shape repeats.
In other words, it is the distance between consecutive corresponding points of the same ''phase (waves ...
which is then passed through a
cuvette
In laboratories, a cuvette () is a small tube-like container with straight sides and a circular or square cross-section. It is sealed at one end, and made of a clear, transparent material such as plastic, glass, or fused quartz. Cuvettes are des ...
containing a solution. A
photoelectric cell collects the light which passes through the cuvette. A measurement is then given for the amount of absorbed light.
Turbidimetry can be used in
biology
Biology is the scientific study of life and living organisms. It is a broad natural science that encompasses a wide range of fields and unifying principles that explain the structure, function, growth, History of life, origin, evolution, and ...
to find the
number of cells in a suspension.
Turbidity-is an expression of optical look of a suspension caused by radiation to the scattered and absorbed wavelength. Scattering of light is elastic so both incident and scattered radiation have same wavelength.
A turbidometer measures the amount of radiation that passes through a fluid in forward direction, analogous to absorption spectrophotometry.
Standard for turbidimetry is prepared by dissolving 5g of hydrazinium (2+) sulfate(N2H4H2SO4) and 50g of hexamethylenetertramine in 1liter of distilled water is defined as 4000 nephelometric Turbidity Unit(NTU)
Application
Determination of water
Clarity of pharma products and drinks
Immunoassay in lab
Turbidimetry offers little advantage than nephelometry in measurement of sensitivity in low level antigen a antibody immunoassay.
Antigen excess and matrix effects are limitations encountered
Immunoturbidimetry
Immunoturbidimetry is an important tool in the broad diagnostic field of clinical chemistry. It is used to determine serum proteins not detectable with classical clinical chemistry methods. Immunoturbidimetry uses the classical antigen-antibody reaction. The antigen-antibody complexes aggregate to form particles that can be optically detected by a photometer.
See also
*
Colorimetry
Colorimetry is "the science and technology used to quantify and describe physically the human color perception".
It is similar to spectrophotometry, but is distinguished by its interest in reducing spectra to the physical correlates of color p ...
*
Turbidity
Turbidity is the cloudiness or haziness of a fluid caused by large numbers of individual particles that are generally invisible to the naked eye, similar to smoke in air. The measurement of turbidity is a key test of both water clarity and wa ...
References
Measurement
Chemical tests
Immunologic tests
Scattering
{{scattering-stub