Formazine

Source: Wikipedia, the free encyclopedia.

Formazine (formazin) is a

heterocyclic polymer produced by reaction of hexamethylenetetramine with hydrazine sulfate
.

Turbidity standards of 5, 50, and 500 NTU

The hexamethylenetetramine tetrahedral cage-like structure, similar to adamantane, serves as molecular building block to form a tridimensional polymeric network.

Formazine is very poorly soluble in water and when directly synthesized in aqueous solution, by simply mixing its two highly soluble precursors, it forms small size

turbidimeters and to control the reproducibility of their measurements. Formazin use was first proposed by Kingsbury et al. (1926) for the rapid standardization of turbidity measurements of albumin in urine.[1][2] The unit is called Formazin Turbidity Unit (FTU). A suspension of 1.25 mg/L hydrazine sulfate and 12.5 mg/L hexamethylenetetramine in water has a turbidity of one FTU.[3][4]

In the

Nephelometric Turbidity Units
(NTU), while the international standard unit is called Formazin Nephelometric Unit (FNU). The most generally applicable unit is Formazin Turbidity Unit (FTU), although different measurement methods can give quite different values as reported in FTU.

Turbidity measurement

For turbidity measurement, a formazine suspension is prepared by mixing solutions of 10 g/L hydrazine sulfate and 100 g/L hexamethylenetetramine with

FTU/FNU
. This is then diluted to a value to suit the instrument range. There is no straightforward relationship between FTU/FAU and NTU/FNU because it depends on the optical characteristics of the particular matter in the sample. A general difficulty encountered for preparing formazine standards is to obtain sufficiently reproducible and accurate results. The preparation temperature is essential because it affects the size of the formazine particles. Uncertainties related to temperature fluctuations are of the order of 1.2% per °C.

The purity of the water used in the preparation of the formazine dispersion is also important as it cannot initially contain colloidal particles. Experience shows that water filtered as required has a residual scatter of about 0.02 FTU = 20 mFTU (inherent brightening effect). This has to be taken into account during

fungi, and yeast
.

See also

References

  1. ^ Kingsbury F. B., Clark C. P., Williams C., and Post A. L. (1926). "The rapid determination of albumin in urine". J. Lab. Clin. Med. 11 (10): 981–989. Archived from the original on 2022-02-24. Retrieved 2022-02-24.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  2. doi:10.1016/S0003-2670(01)83146-9
    .
  3. ISBN 978-0-08-087512-5. Archived
    from the original on 8 July 2014. Retrieved 5 May 2013.
  4. ISBN 978-1-84339-277-4
    . Retrieved 5 May 2013.
  5. ^ "British Pharmacopoeia". Archived from the original on 2022-02-24. Retrieved 2022-02-24.

External links

Retrieved from "https://en.wikipedia.org/w/index.php?title=Formazine&oldid=1174627346"