Simultaneous determination of α-naphthol, β-naphthol and 1-hydroxypyrene in urine by synchronous fluorescence spectrometry using β-cyclodextrin as a sensitiser

Abstract

A novel method for the simultaneous determination of α-naphthol (α-NAP), β-naphthol (β-NAP) and 1-hydroxypyrene (1-OHP) in human urine has been established by using synchronous fluorescence spectrometry. The measurement was carried out in sodium acetate-boroborax buffer solution (pH = 5.0) with β-cyclodextrin (β-CD) enhancing fluorescence. At Δλ = 23 nm, 1-OHP and β-NAP exhibit maximum signal with minimum interferences from α-NAP. At Δλ = 175 nm, the signal of α-NAP is not influenced by the presence of 1-OHP and β-NAP. The signals detected at these three wavelengths, 360.2 nm, 330.6 nm and 296.4 nm, vary linearly when the concentration of 1-OHP, β-NAP and α-NAP is in the range of 0.65–218.3 ng mL−1, 2.8–1441.0 ng mL−1 and 3.6–1586.0 ng mL−1, respectively. The limits of detection (LOD) for α-NAP, β-NAP and 1-OHP were 1.53 ng mL−1, 0.78 ng mL−1 and 0.020 ng mL−1 with relative standard deviations (RSD) of 2.3%, 2.4% and 1.8%, respectively. The proposed method was successfully applied for the simultaneous determination of α-NAP, β-NAP and 1-OHP in human urine samples, and the obtained results were in good agreement with those obtained by the method of high-performance liquid chromatography (HPLC).