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Objective: To establish a method for the determination of butyronitrile and isobutyronitrile in the air of workplace by gas chromatography. Methods: In March 2020, butyronitrile and isobutyronitrile in the air of workplace was collected by silica gel, eluted with methanol, separated and determined by gas chromatogram with flame ionization detector, the characteristics of determination of nitrile and isobutyronitrile by gas chromatography were analyzed. Results: The limit of detection for butyronitrile and isobutyronitrile was 0.33 μg/ml. The linear range of butyronitrile determined by this method was 1.60-1600.00 μg/ml, y=2.295x-3.480, and the coefficient correlation was 0.99998, and the minimum detection concentration was 0.22 mg/m(3) (collected sample volume was 1.50 L) . The within-run precisions were 2.43%-4.12%, the between-run precisions were 1.72%-3.70%, and the desorption rates were 93.26%-98.41%. The linear range of isobutyronitrile determined by this method was 1.52-1520.00 μg/ml, y=2.208x-0.102, and the coefficient correlation was 0.99998, and the minimum detection concentration was 0.22 mg/m(3) (collected sample volume was 1.50 L) . The within-run precisions were 2.52%-3.22%, the between-run precisions were 1.20%-3.82%, and the desorption rates were 96.85%-102.50%. The sealed samples could be stored at least 10 days at room temperature without significant loss. Conclusion: The method has the advantages of good precision, high sensitivity and simple operation. It is suitable for the simultaneous determination of butyronitrile and isobutyronitrile in the air of workplace.
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Air Pollutants, Occupational/analysis , Chromatography, Gas/methods , Nitriles , WorkplaceABSTRACT
OBJECTIVE: To establish a solvent desorption-gas chromatography method for determination of methyl pentane in workplace air. METHODS: Methyl pentane in workplace air was collected with activated carbon tube and desorbed with carbon disulfide, then separated by DB-1 capillary column, detected by flame ionization detector, and quantified by standard curve method. RESULTS: Good linearity was obtained in the range of 1.98-6 600.00 mg/L with the correlation coefficient of 0.999 9. The minimum detection limit and the minimum quantification limit were 0.06 and 0.20 mg/L, respectively. The minimum detection concentration and minimum quantification concentration was 0.04 and 0.14 mg/m~3, respectively(calculated by collecting 1.5 L of air sample). The average desorption efficiency was 97.3%-102.2%. The within-run relative standard deviation(RSD) and the between-run RSD were 0.4%-0.9% and 0.3%-3.0%, respectively. The sampling efficiency was 96.7%-100.0% and the penetration capacity was 8.68 mg. The samples can be stored at room temperature for at least 14 days. CONCLUSION: This method is suitable for methyl pentane detection in workplace air.
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OBJECTIVE: To explore a method for detecting volatile organic compounds(VOCs) in air by a portable gas chromatography-mass spectrometer(GC-MS). METHODS: A portable GC-MS hand-held probe was used for sampling and detection. All effluent components were qualitatively analyzed by the standard spectral library of the United State National Institute of Standards and Technology. The percentage of peak area of the component was calculated by normalization method. The static distribution method was adopted in the semi-quantitative and quantitative analysis using nitrogen as the diluting gas to prepare different mass concentration of 13 kinds of VOCs in the mixed standard gas. The retention time and characteristic ions were used for qualitative analysis, and the quantitated full scanning mode was used for quantitative analysis.RESULTS: The minimum detected mass concentration of the 13 chemical harmful factors was 0.02-0.10 mg/m~3, and the minimum quantitative mass concentration was 0.07-0.38 mg/m~3. The recovery rate was 84.76%-116.56%, and the within-and between-run relative standard deviations were 4.10%-12.50% and 8.17%-14.36%, respectively. CONCLUSION: The portable GC-MS instrument could be used for qualitative alalysis, peak area percentage determination, semi-quantitative and quantitative analysis of VOCs in the workplace air or sudden chemical poisoning accidents.
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OBJECTIVE: To establish the occupational exposure limit for trimethyltin chloride(TMT) in workplace air. METHODS:According to the GBZ/T 210.1-2008 Guide for Establishing Occupational Health Standards--Part 1: Occupational Exposure Limits for Airborne Chemicals in the Workplace, the relevant literatures on toxicology, population epidemiology and foreign occupational exposure limit of TMT were collected and analyzed. A total of 276 workers with TMT occupational exposure were selected as the exposure group and 25 workers without TMT occupational exposure were selected as the control group.Worksite survey of occupational health and occupational medical examination were carried out. Combined with the literature data, the occupational exposure limit of TMT in the workplace air was calculated by using the 90% medical reference level(internal exposure limit) of the urine TMT level of workers who exposed to TMT without moderate hypokalemia. RESULTS: The time-weighted average of TMT in the workplace air is 0.100 mg/m~3 and the short-term exposure limit is 0.200 mg/m~3 in the United States based on total organic tin. The highest concentration of TMT in the workplace air in Germany is 0.005 mg/m~3. The literature data analysis results showed that the incubation period of TMT poisoning is mostly 3-6 days, and the main symptoms of TMT poisoning are hypokalemia in the early stage, followed by neuropsychiatric symptoms such as headache, memory loss and aggressive behavior. The median(M) and the 0-100 th percentile(P_0-P_(100)) of exposure to TMT were 8.35(< 0.20-91.40) μg/m~3 in the exposure group. The individual TMT exposure level of workers in different positions from high to low were crushing, granulation, withdrawal and assembly positions. The M(P_0-P_(100)) of urinary TMT level in the exposure group was 16.94(<0.50-591.14) μg/L. There was a positive correlation between the individual TMT exposure level and urine TMT level in the exposure group(Spearman correlation coefficient=0.62, P<0.01). The detection rate of hypokalemia in the exposure group was higher than that in the control group(26.1% vs 4.0%, P < 0.05). However, there was no significant difference in the detection rate of moderate hypokalemia between the two groups(3.3% vs 0.0%, P>0.05). The 90% medical reference value of urine TMT was 89.90 μg/L in workers exposed to TMT without moderate hypokalemia. CONCLUSION: In order to prevent acute hypokalemia damage caused by TMT, we recommended that the occupational exposure limit of TMT in the workplace air should be set at 0.025 mg/m~3 in China, and this limit should be the maximum allowable concentration.
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OBJECTIVE: To analyze the comparison results of volatile organic components in chemicals tested by occupational health laboratories.METHODS: A total of 37 reference laboratories that participated in the 2019 National Occupational Health Inspection and Testing Institution Laboratory Comparison Chemical Qualitative Testing Comparison organized by Guangdong Occupational Health Testing Center were selected as the research subjects. Headspace gas chromatography-mass spectrometry was used for the determination of volatile organic components in chemicals. The comparison results of reference laboratories were collected and implemented with qualitative and quantitative evaluation. RESULTS: The qualified rates of the qualitative results of the required hazard factors and other hazard factors in the reference laboratories were higher than those of the quantitative results of similar factors with statistical significance(83.78% vs 67.57%, 89.19% vs 56.76%, all P<0.05). There was no significant difference in the qualified rate of qualitative and quantitative results and comprehensive judgment results among each reference laboratory with other hazard factors(83.78% vs 89.19%, 67.57% vs 56.76%, 83.78% vs 89.19%, all P>0.05). The qualified rate of 37 reference laboratories was 89.19%(33/37). It showed no significant difference in the qualified rate of qualitative, quantitative and comprehensive judgment results among the reference laboratories of disease prevention and control system and non-disease prevention and control system(93.75% vs 85.72%, 85.00% vs 61.91%, 93.75% vs 85.52%,all P>0.05). CONCLUSION: There are great differences in the detection ability of volatile organic components on chemicals of each reference laboratory. The ability of qualitative detection is superior to the quantitative detection.
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OBJECTIVE: To prepare and develop a GDH-2 air sampling tube for detecting 12 kinds of chlorobenzenes(CBs) in workplace air and to establish a matching detecting method. METHODS: The self-developed GDH-2 air sampling tube was filled with ion exchange resin and activated carbon, and the mass ratio was 10 ∶1. The GDH-2 air sampling tube was used to collect 12 kinds of CBs with coexistence of gaseous and aerosol in the air. After elution with toluene, they were separated on a chromatographic column and determined by microcell electron capture detector. RESULTS: The quantitative detecting range of the method was 0.51×10~(-3)-6 000.00 mg/L, with the correlation coefficients greater than 0.999 4. The minimum detection concentration was 0.02-61.99 μg/m~3, and the minimum quantitative concentration was 0.05-206.62 μg/m~3. The average desorption efficiency was 90.8%-104.0%. The within-run relative standard deviation(RSD) was 1.0%-5.7%, and the between-run RSD was 3.0%-7.3%. The samples can be stored at room temperature for at least 26 days. CONCLUSION: The self-developed GDH-2 air sampling tube and its matching measuring method can be used for the collection and determination of the 12 kinds of CBs in the air of workplace.
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Acute 1,2-dichloroethane poisoning causes serious illness, deaths and is a social event of great influence. The compilation of Technical Plan for Emergency Treatment of Acute 1,2-Dichloroethane Poisoning provides scientific guidance for effective treatment of 1,2-dichloroethane poisoning events. The plan describes in detail the specific practice and technical requirements of six links in the process of handling emergency of acute 1,2-dichloroethane poisoning, including accident investigation and treatment, risk assessment, collection and testing of samples, medical treatment, health monitoring and emergency response, et al. The key contents of individual protection requirements, investigation content, etiology determination, medical assistance and health education in the disposal of poisoning incidents were clarified, and the procedures and requirements of health education were added. The technical scheme is scientific, objective and operable, which can provide scientific guidance for the effective treatment of 1,2-dichloroethane poisoning accidents.
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OBJECTIVE: To establish a method for simultaneous determination of 12 kinds of chlorobenzene compound(CBs) in workplace air using portable gas chromatography-mass spectrometry(GC-MS) technique. METHODS: The GDH-3 air sampling tube was developed independently, and were used to collect the 12 kinds of CBs in the vapor state and aerosol state in the air. After elution with toluene solvent, portable GC-MS method was used for detection. Fast chromatographic column was used for separation, and then qualitatively analyzed with retention time and characteristics of the ions, and quantitative analyzed by standard curves. RESULTS: The quantitative determination ranges of the 12 kinds of CBs were 0.20-200.00 mg/L. All the correlative coefficients were greater than 0.998 3. All the minimum quantitative concentration was 0.01 mg/m~3, and all the minimum quantitative mass concentration was 0.04 mg/m~(3 )(15 L sample). The average elution efficiency was 88.97%-116.86%. The within-run and the between-run relative standard deviation was 10.15%-13.48% and 12.87%-19.66%, respectively. All the sampling efficiencies were>90.00%. CONCLUSION: The portable GC-MS technique could be used for rapid qualitative and quantitative detection of 12 kinds of CBs in workplace air.
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OBJECTIVE: To investigate the effects of 1,2-dichloroethane( 1,2-DCE) on myelin basic protein( MBP),neuron specific enolase( NSE) and S100 protein in the plasma of SD rats. METHODS: Forty-eight specific pathogen free adult SD rats were randomly divided into control group,low-dose group and high-dose group,with 8 females and 8 males in each group. Rats were given 1,2-DCE orally at the dose of 0,27 and 79 mg / kg body weight every other day( every Wednesday,Monday and Friday) for 4 weeks. After 1,2-DCE administration,8 survived rats( half male and female) were randomly selected in each group. The plasma levels of MBP,NSE and S100 protein were measured using enzyme-linked immunosorbent assay. The blood and urinary samples were collected to assess the concentration of 1,2-DCE and its main metabolites( 2-chlorideacetic acid, 2-chlorideacetaldehyde and 2-chlorideethanol) by gas chromatography. The pathological changes of cerebrum and cerebellum were observed through optical microscope,and the expression of MBP was detected by immunohistochemistry. RESULTS: Rats in high-dose group showed abnormal behavior from the third day of1,2-DCE exposure and 6 rats( 2 females,4 males) died from 1,2-DCE intoxication. Rats in low-dose group and control group appeared normal and no death was observed. MBP level in the plasma of high-dose group was higher than that in the control group( P < 0. 05),but the levels of NSE and S100 protein in each group did not show significant statisticaldifference( P > 0. 05). 1,2-DCE and 2-chloroethanol in the urine were detected in the high-dose group,and were below detection limit in the other two groups. 2-Chloroacetic acid level in high dose-group was significantly higher than that in the low-dose group( P < 0. 05),and was below detection limit in the control group. 2-Chloroacetaldehyde in the urine of each group was below detection limit. 1,2-DCE and its 3 kinds of metabolites were not detected in the plasma of all rats. There was no obvious structural damage,bleeding,edema or necrosis found in the cortex and white matter of cerebrum and cerebellum. The expression of MBP in the choroid plexus epithelial cells were significantly enhanced in the lateral ventricle and the fourth ventricle of rats in the high-dose group,and slight enhanced in rats in the low-dose group. CONCLUSION: MBP may play a role in the toxic effect of 1,2-DCE.
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OBJECTIVE: To establish a method for testing tetrahydrofuran( THF) in workplace air by solvent desorption gas chromatography. METHODS: The air samples were collected by activated carbon tube,desorbed with carbon disulfide solution,then separated by capillary column and detected by flame ionization detector. RESULTS: The linearity range of THF concentration was 1. 78-8 892. 00 mg / L,and the correlation coefficient was 0. 999 9. The minimum detection limit of THF was 0. 09 mg / m3. The minimum quantitative concentration was 0. 27 mg / m3( 3. 00 L air collection). The average desorption efficiency of THF was 94. 29%-96. 46% when placed overnight at the room temperature. The within-run and the between-run relative standard deviation were 0. 30%-0. 91% and 0. 66%-1. 23% respectively. THF sample could be stored at room temperature for at least 8 days. CONCLUSION: The method could be widely applied in sampling and detection of THF in workplace air.
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OBJECTIVE: To explore the effects of aquaporin 4( APQ4) in rat toxic brain edema induced by subacute 1,2-dichloroethane( 1,2-DCE) exposure. METHODS: Thirty-two specific pathogen free healthy adult female SD rats were randomly divided into control( 8 rats),low-dose( 12 rats) and high-dose( 12 rats) groups. The treatment groups were exposed to 1,2-DCE( low-dose: 600 mg / m3; high-dose: 1 800 mg/m3,nose-only) and the control group was exposed to fresh air by dynamic inhalation for 8 hours per day for consecutive 7 days. After exposure,histopathologic changes were examined in the cerebral cortex. Real-time polymerase chain reaction was used to detect the mRNA relative expression of matrix metalloproteinase 2( MMP2),Na-K-Cl cotransporter-1( NKCC1) and AQP4. The Western blotting was used to detect the expression of AQP4 protein in the cerebral cortex. RESULTS: The pathological results showed that the cerebral cortex tissues were loose around the peripheral vessels and the vessels tissue space appeared widen in low-dose exposure group. The pathological change was more serious in high-dose group than low-dose group,with obvious loosen vessels and vacuole. Compared with those of the control group and the low-dose group,the relative expression level of MMP2 mRNA in the high-dose group increased significantly[( 1. 07 ± 0. 41) vs( 1. 56 ± 0. 55),( 1. 21 ± 0. 59) vs( 1. 56 ± 0. 55),P <0. 05],while the the relative expression level of AQP4 mRNA in the high-dose group significantly decreased [( 1. 03 ±0. 25) vs( 0. 81 ± 0. 12),( 1. 00 ± 0. 20) vs( 0. 81 ± 0. 12),P < 0. 05]. The relative expression levels of NKCC1 mRNA in all groups showed no statistical difference [( 1. 03 ± 0. 31) vs( 1. 14 ± 0. 43) vs( 1. 36 ± 0. 50),P > 0. 05]. The relative expression level of AQP4 protein in the high-dose group was lower than that of the control group [( 0. 80 ± 0. 25) vs( 1. 19 ± 0. 42),P < 0. 05]. CONCLUSION: The brain edema induced by subacute inhalation of 1,2-DCE is of mixed types with vasogenic edema as its main symptom. Its pathogenesis is related to the changes of AQP4 expression.
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OBJECTIVE: To study the potential effects of subacute 1-bromopropane( 1-BP) inhalation on the expression of synapse specific biomarkers synaptophysin( SYP),glutamate receptor 2( GluR2) and N-methyl-D-aspartate receptor 2B( NR2B) in the hippocampus of male rats. METHODS: Forty-eight specific pathogen free adult male Wistar rats were randomly divided into control group,low-,medium-,and high-dose groups according to body weight. Each group consisted of 12 rats. By dynamic inhalation intoxication method,the control group was exposed to fresh air,the dose groups were given 1 250,2 500 and 5 000 mg / m3 of 1-BP respectively,6 hours per day,5 days per week for continuous 4 weeks. After the exposure,the rats were executed and the whole brains were separated into cerebrum( included hippocampus),brainstem and cerebellum. Real time quantitative polymerase chain reaction and Western blot were used for detection of SYP,GluR2 and NR2 B mRNA and protein expression in hippocampus. RESULTS: Slow response and muscle strength descended in hind limbs were found in high-dose group in the 3rd week. Body weights of rats in high-dose group were lower than those of control group from the 1st to the 4th week( P < 0. 01). Weights of whole brain,cerebrum and brainstem in high-dose group were lower than those of control group( P < 0. 05). Rats in high-does group were found neuron necrosis in hippocampus cornu ammonis 3 and dentate gyrus region. No significant difference was found in SYP,GluR2 and NR2 B mRNA relative expression in all groups( P > 0. 05). No significant difference was found in SYP protein relative expression in different groups( P > 0. 05). The GluR2 protein relative expression in high-dose group was lower than that of control group( P < 0. 05). The NR2 B protein relative expression was higher than that of control group( P < 0. 05). CONCLUSION: The GluR2 and NR2 B protein expression in hippocampus can be potential biomarkers for 1-BP central neurotoxicity,but its physiological meaning needs further elucidation.