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.

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.

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.

Objective To analyze the overall situation of regular monitoring of occupational hazards in enterprises in Guangdong Province in 2022. Methods Analysis and quality sampling from enterprises were conducted on the occupational hazard regular monitoring reports submitted by various occupational health institutions through the Guangdong Province Occupational Health Quality Control Platform for the year 2022. Results In 2022, a total of 40 129 enterprises in Guangdong Province conducted regular monitoring of occupational hazards, accounting for 5.9%. More than 4.85 million workers were enrolled, of which more than 1.99 million workers were exposed to occupational hazards, with an incidence of 41.1%. The incidence of exposure to chemicals, dust, and noise were 18.2%, 11.9%, and 23.5%, respectively. The incidence of exceeding national standard for chemical substances, dust and noise in enterprises were 2.7%, 3.3%, and 42.7%, respectively. The incidence of exceeding national standard for all occupational hazards increased with the scale of enterprises from micro, small, medium to large enterprises (29.1% vs 46.7% vs 61.3% vs 65.4%, all P<0.05). The top three key industries, with more enterprises exceeding national standard, were metal furniture manufacturing, wooden furniture manufacturing, and other metal daily necessities manufacturing. The concentration of 97 chemical hazardous agents such as silica dust and benzene in work site exceeded the national standard, but less than 1.0% chemical hazardous agents exceeded national standard in most of the chemical-exposed work site. The incidence of noise exceeding national standard was 45.4%, while the incidence of silica dust exceeding national standard was 17.3%. Conclusion The percentage of regular monitoring of occupational hazards in enterprises in Guangdong Province is relatively low. The main occupational hazard that exceeds the national standard was noise, indicating the need for special attention on noise protection in workplace.

OBJECTIVE: To establish a detecting method for sulfur dioxide in workplace air by molecular sieve solid adsorption tube sampling and ion chromatography. METHODS: Air samples were collected by molecular sieve solid adsorption tubes,desorbed by distilled water,oxidized by hydrogen peroxide in weak base system,separated by anion exchange chromatography and detected by conductivity detector. RESULTS: The good linearity range of sulfur dioxide was0. 10-16. 00 mg/L,and the correlation coefficient was 0. 999 8. The detection limit was 0. 02 mg/L,the minimum detectable concentration was 0. 01 mg/m3. The average desorption efficiency was 96. 53%-99. 35%. The within-run and between-run relative standard deviations were 1. 73%-3. 65% and 1. 80%-4. 46% respectively. The samples could be stored at room temperature for at least 14 days. CONCLUSION: This method is suitable for detecting sulfur dioxide in workplace air.