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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.
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Background Tin and its compounds can cause serious harm to human respiratory system and nervous system, but there is no corresponding national standard method for the determination of tin in PM2.5. Objective To establish a method for the determination of tin and its compounds in PM2.5 by atomic fluorescence spectrometry (AFS) after ultrasonic extraction with concentrated hydrochloric acid. Methods We extracted a fixed volume of air at a constant speed through a sampler with preset cutting characteristics to trap PM2.5 in the ambient air on quartz filter membranes. By selecting extraction solvent, comparing extraction temperature and time, and adjusting the acidity of solution to be measured, the sample pretreatment process was optimized, and a method for the determination of tin and its compounds in PM2.5 by AFS was proposed, and its performance indexes such as linearity, detection limit, and lower limit of quantification were obtained. The accuracy and precision of the method were evaluated by the standard addition recovery test with blank quartz filter membranes, and the interference test was carried out by adding standard urban particulate samples. The proposed method and the method recommended by the “Handbook on Monitoring and Protection of Air Pollution (Haze) Effects on Population Health (2020)” (the Handbook) were applied to actual samples, and the results were compared. Results This experiment used concentrated hydrochloric acid as the extraction solvent. The higher the reaction temperature and the longer the reaction time, the higher the recovery rate. Therefore, 70 ℃ water bath ultrasonic extraction for 3 h was selected. In terms of the proposed method, the linear range of detection was from 5.00 μg·L−1 to 50.00 μg·L−1, with a correlation coefficient ≥0.999 and a detection limit of 0.27 μg·L−1. When the quantitative detection of the lower limit was 0.90 μg·L−1，and the sampling volume was 144 m3, the limit of quantification was 1.25 ng·m−3. The recovery rate of standard addition of blank quartz filter membranes was 94.1%-97.5%, with a relative standard deviation ≤3.2%; the recovery rate of standard addition of standard urban particulate matter samples was 93.5%-103.0%, and the relative standard deviation was ≤2.1%, indicating that coexisting components in PM2.5 samples would not affect the determination of tin. For the 10 quartz filter membrane samples of PM2.5 monitoring, the results of tin by the established method (extraction with concentrated hydrochloric acid) were higher than those of the Handbook recommended method (extraction with nitric acid), and the difference is (3.61±0.54) ng·m−3(t=21.303, P<0.05). Conclusion The established method for the determination of tin and its compounds in PM2.5 by AFS after ultrasonic extraction with concentrated hydrochloric acid is simple, accurate, and suitable for laboratory determination of tin and its compounds in large quantities of PM2.5 samples.
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【Objective】 To compare the effect of different combinations of filter membranes on the removal of IgA by component Ⅱ solution. 【Methods】 The dissolved solution of component Ⅱ was filtered with different combinations of filter membranes, and the turbidity, IgA residue, molecular size distribution and purity were compared. 【Results】 After filtering through the combination of NA-16+ Millpore 0.5μ, NA-16+ EmphazeTMAEX HP, and ZetaPlus™ + Emphaze™AEX HP filter membranes, the turbidity of the filtrate decreased by 35.5%(22.4/63.1), 39.2%(24.8/63.3) and 59.8%(37.4/62.5), the IgA residue decreased by 5.8%(14.77/253.70), 20.0%(50.90/254.00) and 44.3%(112.13/253.33), respectively.Molecular size distribution was 99.60%, 99.85% and 100%, and the purity was 100%, 100% and 100%, respectively. 【Conclusion】 The combination of ZetaPlus™ + Emphaze™AEX HP filter membrane can not only effectively remove IgA in the dissolution solution of component Ⅱ with other quality indicators remaining high-level, which can be used in IVIG large-scale production process.
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Objective@#To develop a method for determining diphenylmethane diisocyanate in workplace air by HPLC with impregnated filter membrane.@*Methods@#MDI in workplace air reacted with 1- (2-pyridyl) piperazine on impregnated filter membrane to form MDI-urea derivatives, after elution and filtration, it was detected by HPLC-UV.@*Results@#Limit of detection was 0.003 8 μg/ml and limit of quantification was 0.013 μg/ml. Good linearity was obtained in the range of 0.013~2.000 μg/ml (r=0.999 7) . The precision was 3.10%~8.03% (n=6) , while the recovery was 96.3%~101.9%. Asorption capacity of the membrane was 40.8 μg MDI, and could be stored for 14 days in the light-proof environment of 2~8 ℃.@*Conclusion@#The method optimized testing steps for MDI's standard curve, and provided good guidance for determination of MDI in workplace air with impregnated fiter membrane.
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Objective@#To establish the method for determination of barium sulfate in the air of workplace. @*Methods@#The barium sulfate was collected by dichloride ethylene filter membrane and then processed by alkali fusion method. Inductively coupled plasma optical emission spectrometry (ICP-OES) was used for the detection of barium sulfate. @*Results@#The sampling efficiency was 100%, the linearity of ICP-OES was good at the range of 0.1~100.0 μg/mL, the recovery was ranged from 93.0%~97.8%, the RSD of intra- and inter-batch precision were 3.7%~7.6% and 4.7%~8.8%, respectively. @*Conclusion@#The sampling method and determination method meet the requirements of analysis and apply to the collection and determination of barium sulfate in the air of workplace.
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Objective@#To establish the inductively coupled plasma optical emission spectrometry (ICP-OES) method for determination of cobalt and tungsten in the air of workplace.@*Methods@#The cobalt and tungsten were collected by filter membrane and then digested by nitric acid, inductively coupled plasma optical emission spectrometry (ICP-OES) was used for the detection of cobalt and tungsten.@*Results@#The linearity of tungsten was good at the range of 0.01-1 000 μg/ml with a correlation coefficient of 0.999 9, the LOD and LOQ were 0.006 7 μg/ml and 0.022 μg/ml, respectively. The recovery was ranged from 98%-101%, the RSD of intra-and inter-batch precision were 1.1%-3.0% and 2.1%-3.8%, respectively. The linearity of cobalt was good at the range of 0.01-100 μg/ml with a correlation coefficient of 0.999 9, the LOD and LOQ were 0.001 2 μg/ml and 0.044 μg/ml, respectively. The recovery was ranged from 95%-97%, the RSD of intra-and inter-batch precision were 1.1%-2.4% and 1.1%-2.9%, respectively. The sampling efficiency of tungsten and cobalt were higher than 94%.@*Conclusion@#The linear range, sensitivity and precision of the method was suitable for the detection of tungsten and cobalt in the air of workplace.
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Objective@#To establish the method for determination of titanium dioxide in the air of workplace by inductivehy coupled plasma optical emission spectrometry (ICP-OES) .@*Methods@#The titanium dioxide was collected by filter membrane and then digested by microwave digestion apparatus in the mixed solvents (HNO3∶HF∶H2O=4∶1∶1) , dilutedto 25 ml and detected by ICP-OES.@*Results@#The sampling efficiency was higher than 95%; the linearity of ICP-OES was good at the range of 10-500 μg/ml, the minimum quantitation concentration was 0.72 mg/m3 (as collecting 150 L air sample) , the maximum quantitation concentration was 21.7 mg/m3 (as collecting 960 L air sample) , the recovery was ranged from 99.0%-102.0%, the RSD of intra- and inter-batch precision were 0.5%-3.2% and 1.7%-3.5%, respectively.@*Conclusion@#The sampling method and determination method meet the requirements of guide for establishing occupational health standards-part 4: determinatin methods of air chemicals in workplace (GBZ/T 210.4-2008) , and areapplys to the collection and determination of TiO2 in the air of workplace.