RP-HPLC Determination of Trace Amount of Formaldehyde in Emulsion Polymers with Precolume Derivatization

Free formaldehyde was extracted from the emulsion polymer sample by demulsification and hydrolysis in succession.An aliquot of the supernatant extract was taken,mixed with the derivatizing reagent (i.e,the Nash reagent) and derivatized for 40 min at 50 ℃ in a water bath.The solution containing the derivative of formaldehyde was used for HPLC analysis.Under the specified chromatographic conditions,linear relationship between values of peak area and mass concentration of formaldehyde was obtained in the range of 0.75 mg·L-1 to 7.5 mg·L-1.Detection limit (3S/N) of the method was found to be 3.0 μg·L-1.The proposed method was used in the analysis of 2 substantial samples,on the base of which recovery was tested by adding standard formaldehyde solution at 3 concentration levels (from 15-1 500 mg·kg-1).Results of recovery found were in the range from 92.0% to 104.7%.Precision was tested by taking definite amount of standard formaldehyde solutions and making 7 determinations within a time-period of 2.5 h,value of RSD found was 1.96%.