One-step solid-phase UV spectrophotometric method for phenol determination in vaccines: Development and quality assessment

A solid-phase spectrophotometric technique was used to develop very sensitive, inexpensive, onestep procedure for determination of phenol (UV-SPS procedure). The proposed procedure is based on simultaneous sorption of phenol on an anion exchanger QAE Sephadex A-25 (40 mg), within 10 min at pH 11 and measurement of the intrinsic absorbance of the solid phase in a 1-mm cell at 289 and 500 nm, without previous derivatization. The optimum experimental conditions were investigated and comprehensive quality control of the new procedure was carried out using a prevalidation strategy accompanied by a very informative system of diagnosis. The UV-SPS procedure is characterized with both ideal calibration and analytical evaluation function within analyte working range from 0.3 to 3.0 μmol (6.0 to 60.0 nmol/mL). Random deviations (from ±0.3 to ±5.0%) and systematic deviations (from −3.0 to +4.9%) confirmed the favourable precision and accuracy of the UV-SPS method. Evaluated limiting values (L D = 1.0 μM, L Q = 6.0 μM) showed that this method enables determination of very low levels of phenol. The sensitivity of UV-SPS procedure is 50 times higher than that provided by the corresponding method in solution. The UV-SPS method was successfully applied to the determination of phenol in vaccines (recovery 95.6–103.4%).