[Method for determining o-tolidine in workplace air by gas chromatography].

OBJECTIVE: To establish a method for determining o-tolidine in workplace air by gas chromatography. METHODS: o-tolidine in workplace air was collected with a glass fiber filter, desorbed with methanol, and determined by gas chromatography-flame ionization detector. RESULTS: The concentration of o-tolidine showed a linear relationship with peak area within 0.04∼9.00 µg/ml; the detection limit was 0.04 µg/ml; the minimum detectable concentration was 0.0002 mg/m(3) (calculated by 375 L air sample); the sampling efficiency was 93%∼100%; the elution efficiency was 94%∼96%; the relative standard deviation was 0.8-2.5%. Sample could be stored at 4 °C for at least 8 days and at room temperature for as long as 6 days. CONCLUSION: This determination method meets the requirements of Guide for establishing occupational heath standards-Part 4 Determination methods of air chemicals in workplace (GBZ/T 210.4-2008) and is suitable for determination of o-tolidine in workplace air.

[Ion chromatography for determination of ammonia sampled by silica gel in air of workplace].

OBJECTIVE: To establish an ion chromatography (IC) method for determination of ammonia in air of workplace. METHODS: Ammonia in workplace air was collected in silica gel tube, desorbed with 10 mmol/L methanesulfonic acid by ultrasonic for 10 min, determined by IC. RESULTS: The linearity range was 0.02-1.00 microg/ml. The linear equation was Y = 12041X-187 (r = 0.9997). The limit of quantification was 0.13 mg/m3 (the air volume was 1.5 L). Collection efficiency was 100%. Extraction efficiency was 99%. The relative standard deviation was 4.2%-6.3%. The penetration capacity was more than 264 microg. Sample could be stored for 14 days at least by ambient storage. CONCLUSION: This method is convenient, applicable and sensitive, suitable to determinate ammonia in air of workplace.

Determination, characterization and cytotoxicity on HELF cells of ZnO nanoparticles.

Three kinds of ZnO nanoparticles (NPs) with different size were characterized with transmission electron microscopy (TEM), X-ray diffraction (XRD). The potential cytotoxicity of ZnO NPs with various concentrations has been investigated using human embryonic lung fibroblasts (HELF) cells. The cytotoxicity of ZnO NPs on the normal HELF cell was evaluated by 3-(4,5-dimethylthiazol)-2,5-diphenltetrazoliumhromide (MTT) assay and characterized with photo microscopy and scanning electron microscopy (SEM). The results indicated that ZnO NPs aqueous suspensions with concentrations varying from 2.5 to 150mgL(-1) were harmful to the HELF cells and the cytotoxicity to HELF showed obviously concentration dependence. With concentrations higher than 20mgL(-1), ZnO NPs led to the livability of the tested cells lower than 10%. These results highlighted the need for caution during the use of ZnO NPs above 1.2-1.6mgL(-1) for safety. Finally, an UV-vis spectroscopic approach was developed for the determination of ZnO NPs concentration in the linear range 2-50mgL(-1) (correlation coefficients more than 0.9990), and the detection limit was 1.0mgL(-1).