Quantitative determination of phenol and its derivatives in phenol formaldehyde resin by HPLC
The conditions for the determination of phenol, 4.4-dihydroxydiphenylmethane (4,4-DGDFM), 2.4-dihydroxydiphenylmethane (2,4-DGDFM) and 2,2'-dihydroxydiphenylmethane (2,2-DGDFM) by high-performance liquid chromatography (HPLC) have been optimized. Separation of all substances is achieved in 7 minutes on a column with a reversed-phase sorbent in the gradient elution mode using a water-acetonitrile eluent and spectrophotometric detection at a wavelength of 272 nm. Based on optimized conditions, a procedure for determining the mass fraction of phenol in the concentration range from 0.05 to 5.0 % (by weight) in phenol formaldehyde resin by HPLC with a relative standard deviation of the results not exceeding 1.4 % and a relative error of up to 4.9 % has been developed. A method for measuring the mass fractions of phenol and its three derivatives (2,2-DGDFM, 4,4-DGDFM, 2,4-DGDFM) in phenol formaldehyde resin by HPLC in the concentration range from 5.0 to 50.0 % (by weight) with a relative standard deviation of the results not exceeding 1.4 % and a relative error of no more than 6.7 % has also been developed. For simple and express control of the phenol formaldehyde resin content in acetone, a procedure for measuring the mass fraction of a substance by spectrophotometric method in the concentration range from 20 to 40 % (by weight) with a relative standard deviation in the range of 0.1-4.2 % and a maximum value of the relative error of 8.0% has been developed.