CHEMets FORMALDEHYDE TEST KIT K-4605, 0 - 1 & 1 - 5
PPM
FEATURES
:
Formaldehyde
References: Colorimetric method -- Reagent developed by
Aldrich Chemical Co.
Purpald is a registered trademark of Aldrich Chemical
Co.
Titrimetric method -- ASTM D 2194-79, Concentration of
Formaldehyde Solutions.
Formaldehyde is a highly toxic gas formed naturally by the
incomplete combustion of many organic substances. Commercial
formaldehyde gas is readily soluble in water. Formalin, a 37% by weight
solution of formaldehyde with 10-15% methanol added to prevent
polymerization, is the most readily obtainable form of formaldehyde.
Although toxic, formaldehyde has a variety of industrial uses. It
is used as a raw material in the manufacture of particle board products,
textiles and cosmetics. It is also used in tanning and photo developing
processes and as a disinfectant.
The Colorimetric Method. The color-forming reagent Purpald¨was
developed by chemists at Aldrich Chemical Co. Purpald is subject to
fewer interferences than Shiffs' reagent or chromotropic acid
procedures. A purple colored complex is formed when Purpald in alkaline
solution reacts with formaldehyde. Results are expressed as ppm (mg/L)
CH2O.
Shelf-life. 6 months (Purpald reagent products only). We
recommend stocking quantities that will be used within 5 months.
Refrigeration will significantly extend the shelf-life of these
products.
The Titrimetric Method. CHEMetrics offers a titrimetric method
for formaldehyde, which uses sulfuric acid and sodium sulfite. The end
point indicator, thymolphthalein, provides a sharp color change from
colorless to bright blue. Results are expressed as percent (%)
formaldehyde
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