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Objective To establish a high performance liquid chromatography (HPLC) method for simultaneous determination of six aniline compounds (ADs) in workplace air. Methods GDH-1 air sampling tube was used to collect six co-existing ADs such as aniline, o-toluidine, N-methylaniline, m-methylaniline, p-methylaniline and N,N-dimethylaniline in the vapor and aerosol of workplace air. The samples were desorbed and eluted using a methanol solution containing 1.00% ammonia water, followed by separation on a C18 chromatographic column and detection using a diode array detector. Results The quantification range of the method was 0.19 -253.50 mg/L, with the correlation coefficient of 0.999 9 for all six ADs. The minimum detection range was 0.02-0.06 mg/m3, and the minimum quantitation range was 0.04-0.19 mg/m3 [both calculated for a 15.0 L sample with a desorption (elution) solution volume of 3.00 mL]. The average desorption and elution efficiencies were 92.15%-104.41% (silica gel) and 94.29%-104.29% (filter membrane). The intra-assay relative standard deviation (RSD) ranged from 0.90%-9.72% (silica gel) and 0.57%-6.96% (filter membrane). The inter-assay RSD ranged from 2.03%-9.78% (silica gel) and 2.50%-8.62% (filter membrane). The samples were stable at room temperature for seven days. Conclusion This method can be used for the simultaneous determination of six ADs in workplace air.
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Objective To establish a rapid qualitative analysis method for volatile organic components in chemicals. Methods Headspace gas chromatography-mass spectrometry was used to qualitatively determine 19 volatile organic components, including benzene, 1,2-dichloroethane, and n-hexane, in chemicals. Different sample amounts, heating temperatures, heating times, and sample volumes were analyzed to assess their effects on detection results and optimize sampling conditions. Results Based on the set chromatography, the optimal sampling process of this method was as follows： 5.0 g sample in a 20.0 mL headspace bottle, incubated at 40 ℃ for 30 minutes in a constant-temperature drying incubator, and a 1.00 mL headspace gas injection. The within-run and between-run relative standard deviations of all components ranged from 0.00% to 21.05% and 0.00% to 33.33%, respectively. The samples stored in sealed glass containers were stable at room temperature for at least 60 days. Conclusion This method offers simplicity, good reproducibility, and stability, making it suitable for rapid qualitative analysis of volatile organic components in chemicals.
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Objective To establish an infrared spectrophotometric method for determination of mineral oil mist in workplace air. Methods The mineral oil mist in workplace air was sampled with glass fiber filter membrane and eluted with carbon tetrachloride. Petroleum-like standard solution of carbon tetrachloride was used as the calibration standard, and quantitative analysis was performed using infrared spectrophotometric oil analyzer. Results The sampling efficiency of the glass fiber filter membrane ranged from 94.8% to 99.2%, and the extraction efficiency ranged from 95.6% to 104.2%. The linear range of mineral oil mist was 1.00-120.00 mg/L, with a correlation coefficient of 0.999 4. The detection limit was 0.52 mg/L, and the quantification limit was 1.74 mg/L. The average recovery rate ranged from 98.8% to 104.1%. The within- and between- run relative standard deviations were 2.2%-6.4% and 2.3%-5.2%, respectively. The samples were stable at room temperature for seven days. This method could be used for air sampling of mineral oil mist in workplaces where mineral oil is used. Conclusion The method is sensitive, accurate, and efficient, which is suitable for determining the concentration of mineral oil mist in workplace air.
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OBJECTIVE: To establish a method for simultaneous detection of 2-methoxyethoxy ethanol( 2-MEE) and2-ethoxyethoxy ethanol( 2-ETE) in workplace air by solvent desorption-gas chromatography. METHODS: The 2-MEE and 2-ETE in workplace air were collected by activated carbon tubes and desorbed with methanol-methylene chloride( 5 ∶ 95,V/V),then separated on DB-FFAP capillary chromatographic column,and finally detected using flame ionization detector.RESULTS: The 2-MEE and 2-ETE showed a good linear range in 2. 12-8 464. 00 and 2. 11-8 428. 00 mg/L respectively and the correlation coefficients was 0. 999 8. The minimum quantification limits were 0. 16 and 0. 20 mg/m~3 respectively( 3 L air sample). The average desorption efficiencies were 99. 33%-103. 72% and 99. 61%-104. 07% respectively. The withinrun relative standard deviations( RSDs) were 3. 68%-4. 73% and 3. 47%-4. 39% respectively,and the between-run RSDs were 4. 72%-6. 99% and 4. 77%-6. 28% respectively. The samples could be stored at room temperature for at least14 days. CONCLUSION: This method is simple,sensitive,precise and suitable for simultaneous detection of 2-MEE and 2-ETE in workplace air.
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Experimenting in medicine can be accomplished by virtual reality system. VRML is a tool to build virtual object and scenes which can realize static and animated applications in medicine. However, to creat a real environment, the demanded level of interactivity and dynamics is difficult to achieve. In this paper we describe some approaches and techniques which can realize dynamic 3D. Our demonstration is based on the implementation of a virtual baby model, whose character can be accomplished by external JAVA applications.