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 analyze the problems and differences in workplace on-site sampling and testing skills in external quality assessment in laboratory among occupational health technical service institutions. Methods A total of 108 occupational health technical service institutions nationwide, participated in the external quality assessment in laboratory of the on-site individual sampling operation skills for silica dust (hereinafter refer to as "silica dust sampling assessment") and on-site detection operation skills for carbon monoxide (hereinafter refer to as " carbon monoxide sampling assessment") in 2023, were selected as the research subjects. The result of the assessment was analyzed. Results The qualification rate of the institutions for the silica dust sampling assessment was 98.1%. The unqualified rate of institutions in the Pearl River Delta region was lower than that in non-Pearl River Delta regions (0.0% vs 11.1%, P<0.017). The excellence rate was higher in public institutions than that in private enterprises (73.5% vs 40.0%, P<0.017). The unqualified rate of institutions with permit was lower than that of institutions without permit (0.0% vs 13.3%, P<0.05). The qualification rate of the institutions for the carbon monoxide sampling assessment was 79.4%. The proportion of the institutes, whose results of carbon monoxide standard gas (gas bag) deviation was >±20.0% was higher in private enterprises than that in public institutions (32.8% vs 7.1%, P<0.017). In terms of the normativity of on-site individual sampling for silica dust, the rates of conducting air tightness checks before sampling, correct disassembly and installation and correct placement direction of dust sampling heads, and correct flow for calibration based on the provided dust sampling heads were low, at 53.7%, 33.3%, and 14.8%, respectively. In terms of the normativity of on-site detection of carbon monoxide, the accuracy rate of converting results by on-site detection individuals was low, at only 57.8%. ConclusionIt is necessary to further strengthen the training of theoretical knowledge and practical skills of individuals in occupational health technical service institutions in Guangdong Province, especially to enhance the capacity of occupational health technical services in non-Pearl River Delta regions of the province.

Objective To analyze differential metabolites (DMs) in the urine of workers with occupational nickel exposure using non-targeted metabolomics, and to screen differential metabolic pathways. Methods A total of 30 nickel exposed workers were selected as the exposure group, and 30 administrative staff from the same factory were selected as the control group using the judgment sampling method. Urine samples of the individuals from the two groups were collected. The ultra-high performance liquid chromatography with quadrupole time-of-flight mass spectrometry and non-targeted metabolomics were used to detect and identify metabolites. The differential metabolic profiles were compared between workers of the two groups, and key differential metabolic pathways and potential biomarkers were screened. The association of DMs and urinary nickel level were evaluated by Spearman correlation coefficients. The sensitivity and specificity of biomarkers were assessed by receiver operating characteristic (ROC) curve analysis. Results A total of 418 metabolites were identified in the urine of worker in the exposure and control groups. The result of principal component analysis and orthogonal partial least squares analysis showed that there were 128 DMs in the urine of workers in the exposure group compared with the control group. These DMs were mainly enriched in glutathione metabolism, carnitine synthesis, and amino acid and nucleotide metabolism pathways, including glycine and serine metabolism. The result of correlation analysis and ROC curve analysis revealed that 4-methylcatechol, 4-vinylphenol sulfate, 2-hydroxyphenylacetone sulfate, 2-dodecylbenzenesulfonic acid, and decylbenzenesulfonic acid could be the potential biomarkers for nickel exposure (all area under the ROC curve >0.800). Conclusion There were significant differences in the urinary metabolic profiles of workers with occupational nickel exposure. The five DMs including 4-methylcatechol, 4-vinylphenol sulfate, 2-hydroxyphenylacetone sulfate, 2-dodecylbenzenesulfonic acid, and decylbenzenesulfonic acid. These DMs could be potential biomarkers of occupational nickel exposure.

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 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.

Biotoxins, which include bacterial, fungal, marine, plant, and animal toxins, are widespread in living and occupational environments, posing potential threats to human health. Rapid detection of biotoxins in blood is crucial for preventing health hazards and enabling timely disease diagnosis and treatment. Biosensors and immunoassay technologies have critical advantages in the rapid detection of biotoxins in blood. Common biosensors, such as surface plasmon resonance biosensors and fluorescent biosensors, enhance sensitivity and reduce detection limits through signal amplification. Common immunoassay methods, such as colloidal gold immunochromatography, fluorescence immunochromatography, and chemiluminescence immunoassay, improve detection efficacy and sensitivity through specific antibody-antigen binding and nanotechnology. However, current rapid detection technologies of bitoxins in blood face challenges such as matrix interference and insufficient specificity, and they fall short in high-throughput detection of multiple toxins simultaneously. Future developments should focus on improving sample pretreatment, innovating signal amplification methods, enhancing specificity on recognition of elements, and designing portable detection devices and high-throughput platforms for simultaneous toxin analysis. These advancements aim to improve the sensitivity and reliability of detection methods, providing more accurate and convenient solutions for biotoxin detection in blood.

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.