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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.
Subject(s)
Air Pollutants, Occupational/analysis , Chromatography, Gas/methods , Nitriles , WorkplaceABSTRACT
OBJECTIVE: To analyze the occupational hazard factors and their critical control points in the process of construction of a large-scale construction project.METHODS: The engineering analysis, worksite survey occupational health and occupational hazard factor testing were conducted in a large-scale construction project, and the results were analyzed. RESULTS: During the process of construction of this large-scale construction project, there were many occupational hazard factors such as silicon dust, welding smoke, wood and other dusts, inorganic compounds of manganese, carbon monoxide, carbon dioxide, nitric oxide, ozone, noise, high temperature, hand-transmitted vibration and ultraviolet irradiation, among them, silicon dust and noise were the most common ones. The over standard rates of exposure concentration of short term of total dust and respirable dust in the workplace were 68.2%(15/22) and 40.9%(9/22), and the over standard rates of exposure concentration of time weighted average were 54.5%(12/22) and 13.6%(3/22), respectively. The over standard rates of the noise intensity of area sampling and personal sampling in workplace were 69.2%(45/65) and 61.0%(25/41) respectively. The four hours energy equivalent frequency-weighted acceleration to vibration of three hand-transmitted vibration positions has been detected, and the result has surpassed the occupational exposure limit.The results of other occupational hazard factors such as high temperature, ultraviolet radiation, wood dust, welding smoke, other dust, manganese inorganic compounds, carbon monoxide, carbon dioxide, nitric oxide, nitrogen dioxide, hydrogen sulfide, hydrogen cyanide and ozone all met the occupational exposure limits. CONCLUSION: There are various occupational hazard factors in the process of construction of this large-scale construction project, among them, noise, dust and hand-transmitted vibration are the most prominent hazards.These hazards are the critical control points of this type of construction projects.
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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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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 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 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.