HPLC Determination of Bisphenol S in Kitchen Papers

The shredded kitchen paper sample (0.100 0 g) was immersed with 10 mL of the mixture of n-hexane and tetrahydrofuran (1+1) for 2 h. The liquid was discarded, filter papers were used to absorb the liquid on the surface of kitchen paper sample. The dried kitchen paper sample was extracted ultrasonically for 30 min with 10 mL of methanol at 30℃.The extract was evaporated to dryness by N₂-blowing, and then 1 mL of methanol (6+4) solution was added. The solution was filtered on 0.45 μm filtering membrane. HPLC was applied to the determination of bisphenol S in the filtrate. Luna 5u C₁₈ chromatographic column was used as separation column, and methanol (6+4) solution was used as mobile phase. Detection at 259 nm was adopted in the determination. Linear relationship between values of peak area and mass concentration of bisphenol S was kept in the range of 0.1-100.0 mg·L^-1, with detection limit (3S/N) of 0.3 mg·kg^-1. The proposed method was applied to the analysis of kitchen paper sample, giving values of recovery found by standard addition method in the range of 79.1%-104%. Bisphenol S standard solutions were tested for 6 determinations, and RSDs of determined values were in the range of 0.040%-0.68%.