|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|
Formaldehyde, a toxic substance, is used in the following applications: metal plating baths, textile treatments, biological specimen preservatives, and disinfectants of medical equipment. Commercial formaldehyde gas is readily soluble in water.
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 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.