What is Formaldehyde?
Formaldehyde (CH2O) is a colorless pungent gas that is often stored as an aqueous solution called formalin since the gas easily dissolves in water. Formaldehyde is toxic to humans and has been classified as a human carcinogen based on animal studies. Formaldehyde is found naturally but is also produced industrially on a large scale. It is used in a variety of industrial processes and products such as: metal plating baths; textile treatments; biological specimen preservation; urea-, phenolic-, and melamine-based resins used in composite wood production, and in medical equipment disinfectants.
Why Test for Formaldehyde?
While formaldehyde is commonly found as a gas, it can also contaminate water. Formaldehyde enters water through industrial discharge, leaching from certain plumbing fixtures, or from disinfection by-products. Industrial wastewater monitoring for formaldehyde is often required to ensure it is not released into the environment.
About Our Test Kits
CHEMetrics offers visual test kits in a variety of ranges that utilize the Purpald® method. This method develops a purple color in direct relation to the concentration of formaldehyde present in the sample. Results are expressed as ppm (mg/L) CH2O. The kits designed for higher ranges use CHEMetrics VACUettes which make diluting your sample simple.
Click on a catalog number in the table below for more information or to purchase a test kit.
|Range||MDL||Method||Kit Catalog No.||Refill Catalog No.|
|0-1 & 1-10 ppm||0.1 ppm||Purpald||K-4605||R-4605|
|0-30 & 30-300 ppm||5 ppm||Purpald||K-4605D||R-4605D|
|0-60 & 60-600 ppm||10 ppm||Purpald||K-4605A||R-4605A|
|0-120 & 120-1200 ppm||20 ppm||Purpald||K-4605B||R-4605B|
|0-1200 & 1200-12,000 ppm||200 ppm||Purpald||K-4605C||R-4605C|
The Purpald Method
Reference: Purpald® developed by Aldrich Chemical Co.
Purpald® is subject to fewer interferences than Schiff’s reagent or chromotropic acid procedures. A purple-colored complex is formed when Purpald in alkaline solution reacts with formaldehyde. Results of the Purpald Formaldehyde water test kits are expressed as ppm (mg/L) CH2O.
Shelf-life of the Purpald Reagent: five months. We recommend stocking quantities that will be used within four months.