Objective:To set up a new method to determine the nickel of urine in urine using dispersive liquid-liquid microextraction (DLLME) coupled with graphite furnace atomic absorption spectrometry (GFAAS) .Methods:From September 2018 to September 2019, the methanol, pyrrolidine dithiocarbamate and ionic liquid 1-hexyl-3-methyl-imidazolium hexafluorophosphate were used as dispersive solvent, the chelating agent and extraction solvent for the preconcentration of nickel, respectively. After adding into buffer solution of pH 9, ultrasonic dissolving for 10 minutes, centrifugal separation and then discarding the supernatant, the precipitate was saved. Dissolving the precipitate by methanol, mixing thoroughly on a vortex mixer, the 15 μl of the mixed solution was used for determination by graphite furnace atomic absorption spectrometry.Results:The linear correlation coefficient of urine nickel concentration in the range of 2.0-10.0 μg/L, r=0.999, with the detection limitation of 0.43 μg/L. The recovery rate and the relative standard deviations were 95.6% -103.7% and 2.53% -4.82%, respectively. Conclusion:The method, which has low detection limit, high recovery rate and good precision, is suitable for the determination of nickel in urine for the occupational populations exposure to nickel and non-occupational exposure.

Objective:To establish a method for the determination of bisphenol S in urine using dispersive liquid-liquid microextraction (DLLME) coupled with high performance liquid chromatography (HPLC) .Methods:The acetonitrile, octanol were used as extraction solvent, dispersive solvent respectively, for the preconcentration of bisphenol S. The optimal extraction conditions were optimized by single factor rotations, and methodological performance index were tested.Results:The linear correlation coefficient of bisphenol S in the range of 0.0-160 μg/L is greater than 0.999. The detection limit of this method was 0.76 μg/L, and the recovery rates were 88.06%-103.81%. The intra-and inter-day precisions were 1.78%-2.85% and 2.65%-4.25%, respectively.Conclusion:The method is reliable and sensitive. It is suitable for the determination of bisphenol S in urine samples for occupational exposure populations and non-professional.

Objective:To set up a new method to determine the nickel of urine in urine using dispersive liquid-liquid microextraction (DLLME) coupled with graphite furnace atomic absorption spectrometry (GFAAS) .Methods:From September 2018 to September 2019, the methanol, pyrrolidine dithiocarbamate and ionic liquid 1-hexyl-3-methyl-imidazolium hexafluorophosphate were used as dispersive solvent, the chelating agent and extraction solvent for the preconcentration of nickel, respectively. After adding into buffer solution of pH 9, ultrasonic dissolving for 10 minutes, centrifugal separation and then discarding the supernatant, the precipitate was saved. Dissolving the precipitate by methanol, mixing thoroughly on a vortex mixer, the 15 μl of the mixed solution was used for determination by graphite furnace atomic absorption spectrometry.Results:The linear correlation coefficient of urine nickel concentration in the range of 2.0-10.0 μg/L, r=0.999, with the detection limitation of 0.43 μg/L. The recovery rate and the relative standard deviations were 95.6% -103.7% and 2.53% -4.82%, respectively. Conclusion:The method, which has low detection limit, high recovery rate and good precision, is suitable for the determination of nickel in urine for the occupational populations exposure to nickel and non-occupational exposure.

Objective:To establish a method for the determination of bisphenol S in urine using dispersive liquid-liquid microextraction (DLLME) coupled with high performance liquid chromatography (HPLC) .Methods:The acetonitrile, octanol were used as extraction solvent, dispersive solvent respectively, for the preconcentration of bisphenol S. The optimal extraction conditions were optimized by single factor rotations, and methodological performance index were tested.Results:The linear correlation coefficient of bisphenol S in the range of 0.0-160 μg/L is greater than 0.999. The detection limit of this method was 0.76 μg/L, and the recovery rates were 88.06%-103.81%. The intra-and inter-day precisions were 1.78%-2.85% and 2.65%-4.25%, respectively.Conclusion:The method is reliable and sensitive. It is suitable for the determination of bisphenol S in urine samples for occupational exposure populations and non-professional.