Method for measuring formaldehyde in solutions containing certain formaldehyde-releasing biocides
A method for measuring formaldehyde in an aqueous solution of an oxazolidine or hexahydro-1,3,5-triazine biocide; the method comprising separating an amino alcohol produced by hydrolysis of the biocide via mixed mode chromatography and detecting the amino alcohol using a charged aerosol detector or an evaporative light scattering detector.
1. A method for measuring formaldehyde in an aqueous solution of an oxazolidine or hexahydro-1,3,5-triazine biocide; said method comprising separating an amino alcohol produced by hydrolysis of said biocide via mixed mode chromatography and detecting said amino alcohol using a charged aerosol detector or an evaporative light scattering detector.
2. The method of claim 1 in which the oxazolidine or hexahydro-1,3,5-triazine biocide hydrolyzes to produce an amino alcohol having of formula
wherein R 1 is hydrogen, C 1 -C 4 alkyl or hydroxymethyl and R 2 is hydrogen or C 1 -C 4 alkyl.
3. The method of claim 2 in which the oxazolidine or hexahydro-1,3,5-triazine biocide is 4,4-dimethyloxazolidine, 5-ethyl-3,7-dioxa-1-azabicyclo[3,3,0]octane, N,N-methylenebis(5-methyloxazolidine), N,N,N-tris(2-hydroxyethyl)hexahydrotriazine or N,N,N-tris(2-hydroxypropyl)hexahydrotriazine.
4. The method of claim 3 in which a charged aerosol detector is used.
5. The method of claim 4 in which the mixed mode chromatography uses a stationary phase comprising an alkyl chain of least eight carbon atoms and a negatively charged group.
6. The method of claim 5 in which the negatively charged group is a sulfonic acid, a carboxylic acid or a salt of a sulfonic or carboxylic acid.
7. The method of claim 6 in which the oxazolidine or hexahydro-1,3,5-triazine biocide is 4,4-dimethyloxazolidine, 5-ethyl-3,7-dioxa-1-azabicyclo[3,3,0]octane or N,N-methylenebis(5-methyloxazolidine).