Determination of nonylphenol and short ethoxy chain nonylphenols on a normal phase silica-gel column high performance liquid chromatography

High performance liquid chromatography (HPLC) on a normal phase silica-gel column with isocratic elution method was established to determine nonylphenol (NP) and short ethoxy chain nonylphenols (NPnEO n = 1-3). NP and NPnEO were separated on a Cosmosil packed column 5SL-II (250 mm x 4.6 mm i. d., 5 μm) using ethyl acetate-ethanol as mobile phase at a flow rate of 1.0 mL/min and detected at 281 nm. Within 10 minutes all of the target compounds were eluted and separated. The limit of detection for NP and NPnEO (n = 1-3) were 0.1 mg/L and 0.5 mg/L (n = 1-3) respectively. The relative standard deviations of NP, NPEO, NP2EO and NP3EO were 1.4%, 1.6%, 2.5% and 1.4%, respectively.