OBJECTIVETo establish the method of high-performance liquid chromatography (HPLC) for the determination of N-isopropylaniline in workplace air.

METHODSN-isopropylaniline in the air was collected by silicone tube, and was then dissolved by acetonitrile and determined by HPLC-UV detector.

RESULTSThere was a linear relationship within the range of 0.0-100.0 µg/ml with the method, and the regression equation was y=22 863x+10 665(r=0.999 9); the detection limit was 0.005 µg/ml, and the minimum detectable concentration was 1.7x10(-3) mg/m3 (3.0 L sampling volume); the average recoveries of standard addition were 96.2%-101.3%. The within-run precision was 2.31%-2.99%, and the between-run precision was 3.21%-4.55%. The average desorption efficiency was 97.6%, the breakthrough volume was more than 8.12 mg, the sampling efficiency waE 100%, and the samples could be stored for at least 7 days at room temperature.

CONCLUSIONThe indicators ol the method all meet the requirements of GBZ/T 210.4-2008 (Determination methods of air chemicals in workplace), and can be used for the determination of N-isopropylaniline in workplace air.

Air Pollutants, Occupational ; analysis ; Aniline Compounds ; analysis ; Chromatography, High Pressure Liquid ; Limit of Detection ; Workplace

Objective:To establish a gas chromatography method for detecting isobutyl methacrylate in workplace air.Methods:From July to October 2019, isobutyl methacrylate in workplace air was collected by activated charcoal tube, absorbed using carbon disulfide and analyzed by gas chromatography (FID) with FFAP capillary column.Results:The linear range of isobutyl methacrylate in the method was 0-800 μg/ml, the correlation coefficient was 0.99993. The detection limit was 0.35 μg/ml. The lowest detected concentration was 0.12 mg/m 3. The within-run precision was 2.06%-2.72%, the between-run precision was 3.03%-3.83%. The rates of desorption was 96.7%. The breakthrough volume was 14.46 mg. The average sampling efficience was 100%. The samples could be stored at room temperature for 7 days. Conclusion:The method is simple, highly sensitive and precise. Isobutyl methacrylate in workplace air could be determined accurately.

Objective: To establish the method of detecting the concentrations of diphenylamine in air of workplace with high performance liquid chromatographic (HPLC) . Methods: According to standards of methods for determining the chemical substances in workplace air, diphenylamine in the air was collected by glass fiber filter treated with sulfuric acid, then dissolved by methanol and determined by high performance liquid chromatography with UV-detector. Results: There was a linear relationship within the range of 0-30.0 μg/ml, and regression equation was y=8425.6x-150.7, correlation coefficient was 0.999 9, the detection limit was 0.045 μg/ml. The lowest detected concentration was 0.030 mg/m³ (sampling volume 15 L) . The within-run precision was 2.41 ℅-3.02%, the between-run precision was 3.11%-4.45%. The desorption efficiencies was 97.8℅ and the sampling efficiencies were 100%. The samples in glass fiber filter could be stored for 7 d at room temperature. Conclusion The present method could meet with the requirements of Guide for establishing occupational health standards-Part 4 Determination methods of air chemicals in workplace and be feasible for determination of diphenylamine in workplace air.

Objective:To establish a gas chromatography method for detecting isobutyl methacrylate in workplace air.Methods:From July to October 2019, isobutyl methacrylate in workplace air was collected by activated charcoal tube, absorbed using carbon disulfide and analyzed by gas chromatography (FID) with FFAP capillary column.Results:The linear range of isobutyl methacrylate in the method was 0-800 μg/ml, the correlation coefficient was 0.99993. The detection limit was 0.35 μg/ml. The lowest detected concentration was 0.12 mg/m 3. The within-run precision was 2.06%-2.72%, the between-run precision was 3.03%-3.83%. The rates of desorption was 96.7%. The breakthrough volume was 14.46 mg. The average sampling efficience was 100%. The samples could be stored at room temperature for 7 days. Conclusion:The method is simple, highly sensitive and precise. Isobutyl methacrylate in workplace air could be determined accurately.

OBJECTIVETo establish a method for the determination of N-butylbenzene in the workplace atmosphere by gas chromatography.

METHODSN-butylbenzene in the workplace atmosphere was collected by activated charcoal tube, desorbed using carbon disulfide, and determined by capillary column gas chromatography.

RESULTSThe method showed a linear relationship within the range of 0∼100 µg/ml. The regression equation was y = 0.870x-0.014, with the correlation coefficient r being 0.999 9. The limit of detection was 0.32 µg/ml. The minimum detectable concentration was 0.21 mg/m³ (with sampled air volume of 1.5 L). The average spike recovery rate was 97.8%∼102.6%. The within-run precision was 3.06% and the between-run precision was 3.64%. The rate of average desorption was 99.6%. The breakthrough volume was 6.34 mg. The sampling efficiency was 100%. The samples could be stored for at least 7 days at room temperature.

CONCLUSIONAll parameters of the method meet the requirements of GBZ/T 210.4-2008 "Guide for establishing occupational health standards-Part 4 Determination methods of air chemicals in workplace" and can be applied for the determination of N-butylbenzene in workplace atmosphere.

Air ; analysis ; Air Pollutants, Occupational ; analysis ; Benzene Derivatives ; analysis ; Chromatography, Gas ; methods ; Linear Models ; Workplace

OBJECTIVETo establish a method for determination of chloropicrin in the air of workplace by gas chromatography with liquid absorption collection.

METHODSChloropicrin in sample air was collected by absolute ethyl alcohol in a porous glass plate absorption tube. Following direct sample loading, samples were separated by gas chromatography and detected with a micro-electron capture detector. The present method was compared with the national standard method.

RESULTSThe range of linearity was 0-3.0 µg/ml, and the regression equation was y = 3488.80x-57.84, with a correlation coefficient of 0.999 4. The detection limit was 0.003 µg/ml, with a minimum detectable concentration of 0.005 mg/m³ based on a 3.0 L sampling volume. The average recovery rate was 98.9%∼103.2%. The within-run precision was 0.96%-2.12%, and the between-run precision was 2.75%-4.59%. The sampling efficiency was 98.6%. Samples in porous glass plate absorption tube could be stored at 4 °C for at least 5 days. The result ratio of this method to the national standard method was 97.7%-108.0% .

CONCLUSIONThe present method meets the requirements of "Guide for establishing occupational health standards-Part 4: Determination methods of air chemicals in workplace" (GBZ/T 210.4-2008), and is feasible for determination of chloropicrin in the air of workplace.

Air ; analysis ; Air Pollutants, Occupational ; analysis ; Chromatography, Gas ; methods ; Hydrocarbons, Chlorinated ; analysis ; Workplace

Objective To construct a model of Graves'disease ( GD ) with ( or ) Graves'ophthalmopathy ( GO) in BALB/c mice by immunization with pcDNA3. 1/TSHR289. Methods pcDNA3. 1/TSHR289 was injected into the bilateral gastrocnemius muscle of 35 model mice and electroporation was immediately performed. 10 control mice were injected with sterile saline and electroporated, while 5 blank mice were injected with sterile saline only. Each group of mice was immunized at 1, 4, 7, and 10 weeks, respectively. Serum total T4 , TSH, TSAb, and TSBAb were measured before immunization, 2 weeks after each immunization, as well as 5 and 8 weeks after the last immunization. CT scan was used to evaluate the morphological changes of the eyes of the mice.99m TcO4- imaging was used to measure the thyroid uptake function, and the pathological changes of the thyroid and orbital tissues were evaluated by HE staining. Results After the 2nd time immunization, the serum concentrations of TT4 , TSAb and TSBAb in GD mice were significantly higher than those of control and blank groups( F=13.781, 31.435, 36.112, P<0.01, respectively).The TSH continued to be significantly lower than that of control and blank groups(F=13.966, P<0.01) . After the 4th time immunizations, the ability of uptaking99m TcO4- in GD mice thyroid was significantly enhanced compared with the control group. The thyroid goiter with a large amount of lymphocyte infiltration, and the thyroid follicle was thin. CT scan of GO mice showed thickening and swelling of the extraocular muscles, and no abnormalities in tendon and muscle attachment points. HE staining showed thickening of extraocular muscle fibers, lymphocyte infiltration of extraocular muscles and orbital tissue, increased hyaluronic acid, and infiltration of fat cells. Conclusion GD or GO model can be successfully induced by multiple intramuscular injection of pcDNA3.1/TSHR289 in BALB/c mice.