A rapid, simple method for determining formaldehyde in drinking water using colorimetric-solid phase extraction.
Formaldehyde has been detected in drinking water supplies across the globe and on board NASA spacecraft. A rapid, simple, microgravity-compatible technique for measuring this contaminant in water supplies using colorimetric-solid phase extraction (C-SPE) is described. This method involves collecting a water sample into a syringe by passage through a cartridge that contains sodium hydroxide, to adjust pH, and Purpald, which is a well-established colorimetric reagent for aldehydes. After completing the reaction in the syringe by agitating for 2 min on a shaker at 400 rpm, the 1.0-mL alkaline sample is passed through an extraction disk that retains the purple product. The amount of concentrated product is then measured on-disk using diffuse reflectance spectroscopy, and compared to a calibration plot generated from Kubelka-Munk transformations of the reflectance data at 700 nm to determine the formaldehyde concentration. This method is capable of determining formaldehyde concentrations from 0.08 to 20 ppm with a total work-up time of less than 3 min using only 1-mL samples.
Hill
April A
AA
Department of Chemistry, Institute for Combinatorial Discovery, Ames Laboratory-USDOE, Iowa State University, Ames, IA 50011, USA.
Lipert
Robert J
RJ
Fritz
James S
JS
Porter
Marc D
MD
D002138:Calibration; D004784:Environmental Monitoring / Q000295:instrumentation / Q000379:methods; D005557:Formaldehyde / Q000032:analysis*; D006112:Gravitation; D006863:Hydrogen-Ion Concentration; D012972:Sodium Hydroxide / Q000032:analysis; D012984:Software; D052616:Solid Phase Extraction / Q000379:methods*; D013053:Spectrophotometry / Q000379:methods*; D013997:Time Factors; D014867:Water / Q000032:analysis; D014874:Water Pollutants, Chemical / Q000032:analysis; D014881:Water Supply / Q000032:analysis*
D014874:Water Pollutants, Chemical; D014867:Water; D005557:Formaldehyde; D012972:Sodium Hydroxide