Abstract: 4-Nonyphenol was determined by resonance scattering spectrometry as its derivatization product with DNS-Cl.The derivatization reaction was carrried out in 0.5 mol·L-1 Na2CO3 solution,and resonance scattering spectrum of the reaction product was observed in the wavelength range of 300-600 nm,with its peak at 396.8 nm.Linear relationship between the values of increase in intensity of resonance scattering(ΔI) and concentration of 4-nonylphenol was obtained in the range of 6.20×10-4-6.00×10-2mg·L-1,with its detection limit of 0.20 μg·L-1.In combination with separation by solid phase extraction on C18 column,the proposed method was used in the determination of 4-nonylphenol in environmental water samples,giving values of recovery in the range of 91.25%-94.50% and values of RSD′s(n=7) less than 4.0%.