[Determination of residual N,N-dimethylformamide in fluorescent brightening agent CBS by reversed-phase high...

A method for the determination of N,N-dimethylformamide (DMF) residue in fluorescent brightening agent CBS by reversed-phase high performance liquid chromatography (RP-HPLC) was established. An Ameritech Accurasil C18 column (150 mm x 4.6 mm, 5 microm) was used with methanol-water as the mobile phase with gradient elution. The flow rate of the mobile phase was 1.0 mL/min and the detection wavelength was 205 nm. The column temperature was 30 degrees C and the injection volume was 5 microL. There was a good linear relationship between the peak area and the concentration of DMF in the range of 0.19 - 141 mg/L. The recoveries of DMF were 98.4% - 107.3% at the spiked levels of 0.2344% and 0.4678%. The limit of detection was 0.019%. The relative standard deviation was 1.73%. This method can be used for the determination of DMF in fluorescent brightening agent CBS quickly and accurately.