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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 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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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.