Objective: To establish a method for determining cyclohexanol in urine by headspace solid-phase microextraction (HS/SPME) coupled with gas chromatography (GC) . Methods: After the urine sample was hydrolyzed by β-glucuronidase, 2.0 g of NaCl was added, then the analyte in urine was adsorbed by a CAR/PDMS solid phase micro-extraction head in a water bath at 50 ℃ for 20 min. And the extraction head was inserted into the gas chromatograph gasification chamber to desorb, the analyte was detected after separated by the capillary through the flame ionization detector. Results: The linear range of the method was 0.1-5.0 mg/L with the correlation coefficients (r) 0.999. The average recovery was 84.5%-96.3%, the inter-day precision was 3.81%-6.00%, and the detection limit was 0.03 mg/L. Conclusion The method is founded to be low detection limit, simple operation and no need of organic solvent. So it is suitable for the detection of cyclohexanol in urine of occupational exposure to cyclohexanone.

Objective: To establish a method for the determination of 1-methoxy-2-propanol in urine using headspace solid phase micro-extraction coupled with gas chromatography. Methods: The 1-methoxy-2-propanol was enriched by headspace solid phase micro-extraction fiber coated with carbene/polydimethylsiloxane (CAR/PDMS) . Single factor rotation method was used to optimize the conditions of extraction temperature, salt amount, and extraction time. The separation was performed on DB-5 (30 m×0.32 mm×0.25 μm) capillary column and detected with flame ionization detector. The quantification was based on the standard curve. Results: The concentration of 1-methoxy-2-propanol in urine was linear in the range of 0.50-10.0 mg/L, and the linear correlation coefficient was 0.9993. The detection limit of the method was 0.14 mg/L, and the limit of quantification was 0.45 mg/L. The recovery was 85.8% to 104.7%, and the RSD of intra- and inter-batch precision were 3.25%-6.65% and 0.81%-3.96%, respectively. Conclusion The method is high sensitivity and simple operation, and is suitable for the determination of 1-methoxy-2-propanol in urine of occupational exposure population.

Objective:To establish a method for the determination of manganese in urine with graphite furnace atomic absorption spectrometry (GFAAS) by using ionic liquid microextraction.Methods:The ethanol, 8-hydroxyquinoline and ionic liquid 1-octyl-3-methyl-imidazolium hexafluorophosphate were used as dispersive solvent, chelating agent and extraction solvent respectively, for the preconcentration of manganese. After the optimal extraction conditions were optimized by single factor rotations, evaluate the performance indicators such as methodological precision, accuracy, and detection limit.Results:The linear range of urine manganese was 0.0-1.6 μg/L, and the correlation coefficient of standard curve line was 0.992, the detection limit was 0.03 μg/L, the recovery of sample spiked was 84.90%-96.50%, and the relative standard deviation was 0.36%-1.84%.Conclusion:The method has the advantages of low detection limit, high recovery rate and high sensitivity. It is suitable for the determination of manganese in urine samples from occupational exposure populations and the general population.

Objective:To establish a method for the determination of manganese in urine with graphite furnace atomic absorption spectrometry (GFAAS) by using ionic liquid microextraction.Methods:The ethanol, 8-hydroxyquinoline and ionic liquid 1-octyl-3-methyl-imidazolium hexafluorophosphate were used as dispersive solvent, chelating agent and extraction solvent respectively, for the preconcentration of manganese. After the optimal extraction conditions were optimized by single factor rotations, evaluate the performance indicators such as methodological precision, accuracy, and detection limit.Results:The linear range of urine manganese was 0.0-1.6 μg/L, and the correlation coefficient of standard curve line was 0.992, the detection limit was 0.03 μg/L, the recovery of sample spiked was 84.90%-96.50%, and the relative standard deviation was 0.36%-1.84%.Conclusion:The method has the advantages of low detection limit, high recovery rate and high sensitivity. It is suitable for the determination of manganese in urine samples from occupational exposure populations and the general population.

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 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 mandelic acid and phenylglyoxylic acid in the urine of styrene by dispersive liquid-liquid microextraction-high coupled with high performance liquid chromatography.Methods:N-octanol was used as an extractant and ethanol was used as a dispersing agent. The phenylglycolic acid and phenylglyoxylic acid in the urine were extracted, and the upper liquid was taken after vortexing and centrifuged, and then was injected into HPLC for analysis.Results:The linear correlation coefficient of the concentration of phenylglycolic acid in the range of 0~10.0 mg/L was greater than 0.999. The detection limit of the method was 9.9 μg/L, the recovery rates were 86.1%~101.6%. The intraday RSDs of the method were 1.07%~3.76%, and the interday RSDs were 1.24%~3.33%. The linear correlation coefficient of phenylglyoxylic acid in the range of 0.0~2.0 mg/L is greater than 0.999. The detection limit of the method was 2.6 μg/L, the recovery rates were 88.8%~100.3%. The intraday RSDs of the method were 1.02%~ 3.17%, and the interday RSDs were 1.59%~2.41%.Conclusion:The method has low detection limit, high enrichment ratio and good sensitivity, and is suitable for determination of phenylglycolic acid and phenylglyoxylic acid in urine of occupational exposure to styrene.

Objective:To establish a method for the determination of mandelic acid and phenylglyoxylic acid in the urine of styrene by dispersive liquid-liquid microextraction-high coupled with high performance liquid chromatography.Methods:N-octanol was used as an extractant and ethanol was used as a dispersing agent. The phenylglycolic acid and phenylglyoxylic acid in the urine were extracted, and the upper liquid was taken after vortexing and centrifuged, and then was injected into HPLC for analysis.Results:The linear correlation coefficient of the concentration of phenylglycolic acid in the range of 0~10.0 mg/L was greater than 0.999. The detection limit of the method was 9.9 μg/L, the recovery rates were 86.1%~101.6%. The intraday RSDs of the method were 1.07%~3.76%, and the interday RSDs were 1.24%~3.33%. The linear correlation coefficient of phenylglyoxylic acid in the range of 0.0~2.0 mg/L is greater than 0.999. The detection limit of the method was 2.6 μg/L, the recovery rates were 88.8%~100.3%. The intraday RSDs of the method were 1.02%~ 3.17%, and the interday RSDs were 1.59%~2.41%.Conclusion:The method has low detection limit, high enrichment ratio and good sensitivity, and is suitable for determination of phenylglycolic acid and phenylglyoxylic acid in urine of occupational exposure to styrene.