Colorimetric monitoring of solid-phase aldehydes using 2,4-dinitrophenylhydrazine.
A simple and rapid method to achieve colorimetric monitoring of resin-bound aldehydes, based on ambient temperature reaction with 2,4-dinitrophenylhydrazine (DNPH) in the presence of dilute acid, has been developed as an adjunct to solid-phase organic synthesis and combinatorial chemistry. By this test, the presence of aldehydes is indicated by a red to dark-orange appearance, within a minute. Alternatively, resins that are free of aldehydes or in which aldehyde functions have reacted completely retain their original color. The DNPH test was demonstrated for poly(ethylene glycol)-polystyrene (PEG-PS), aminomethyl polystyrene (AMP), cross-linked ethoxylate acrylate resin (CLEAR), and acryloylated O,O'-bis(2-aminopropyl)poly(ethylene glycol) (PEGA) supports and gave results visible to the naked eye at levels as low as 18 micromol of aldehyde per gram of resin.
Shannon
Simon K
SK
Department of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis, MN 55455, USA.
Barany
George
G
D000179:Acrylates / Q000032:analysis / Q000737:chemistry; D000447:Aldehydes / Q000032:analysis* / Q000737:chemistry; D003124:Colorimetry / Q000379:methods*; D006834:Hydrazines / Q000737:chemistry; D007202:Indicators and Reagents; D007659:Ketones / Q000737:chemistry; D015394:Molecular Structure; D011092:Polyethylene Glycols / Q000032:analysis / Q000737:chemistry; D011137:Polystyrenes / Q000032:analysis / Q000737:chemistry; D012117:Resins, Synthetic / Q000032:analysis / Q000737:chemistry; D012997:Solvents / Q000737:chemistry
D000179:Acrylates; D000447:Aldehydes; D006834:Hydrazines; D007202:Indicators and Reagents; D007659:Ketones; D011137:Polystyrenes; D012117:Resins, Synthetic; D012997:Solvents; C446799:dinitrophenylhydrazine; C103390:polyethylene glycol-polystyrene; D011092:Polyethylene Glycols