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Objective: To establish a solvent desorption-gas chromatography method for determination of dimethyl carbonate (DMC) in workplace air. Methods: The air samples were collected using activated carbon tubes, desorbed by carbon disulfide, separated by dimethylpolysiloxane capillary columns, and detected by a flame ionization detector. Results: The linear range of DMC was 2.14 to 1.07×104 mg/L, and the correlation coefficient was greater than 0.999. The detection limit was 0.14 mg/L, the lower limit of quantification was 0.47 mg/L, the minimum detection concentration was 0.10 mg/m3, and the minimum quantification concentration was 0.32 mg/m3 (based on 1.5 L workplace air). The average desorption efficiency of the method was 96.2% to 102.0%. Both the within-run and between-run relative standard deviations were 0.9% to 2.3%. The samples could be stored for at least seven days at four celsius degree. Conclusion: This method shows high desorption efficiency, high sensitivity, good precision and is simple in using. It can be used for the determination of DMC in workplace air.
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OBJECTIVE: To improve the standard detection method for acetaldehyde, butyraldehyde and isobutyraldehyde in the air of workplace. METHODS: Acetaldehyde, butyraldehyde and isobutyraldehyde in the air of workplace were collected using silica gel tube, desorbed with 45.0% ethanol, separated by a capillary column and detected by a flame ionization detector. RESULTS: The linear range of this method for detecting acetaldehyde, butyraldehyde and isobutyraldehyde were 1.57-1 568.00, 1.60-1 600.00 and 1.59-1 588.00 mg/L, respectively. All the correlation coefficients were greater than 0.999. The detection limits were 0.52, 0.46 and 0.54 mg/L, respectively. The desorption efficiency was 91.0%-103.0%. The within-run relative standard deviation(RSD) was 0.7%-1.7%.The between-run RSD was 2.0%-3.7%. The samples could be stored for at least 10 days at room temperature. CONCLUSION: This method can be used for simultaneous detection of acetaldehyde, butyraldehyde and isobutyraldehyde in the air of workplace.
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OBJECTIVE: To establish a method for simultaneous determination of chlorobenzene, p-dichlorobenzene and o-dichlorobenzene in workplace air by portable gas chromatography-mass spectrometry(GC-MS). METHODS: The portable GC-MS heat tracing sampling probe was used for sampling. Samples were separated with LTM DB-5 MS rapid chromatographic column. The qualitative analysis was based on retention times and characteristic ions, and the quantification was based on standard curves. RESULTS: The linear correlation coefficient of this method was higher than 0.999 6. The minimum detectable concentrations were 0.03, 0.03 and 0.06 mg/m~3, and the minimum quantification concentrations were 0.10, 0.10 and 0.20 mg/m~3. The recovery rates were 84.68%-92.61%, 86.27%-93.92% and 82.31%-92.36% respectively for three chlorobenzenes compounds. The within-run relative standard deviations(RSD) were 8.51%-9.34%, 7.93%-9.19%, 5.47%-7.48% respectively for three chlorobenzenes compounds, the between-run RSD were 7.29%-9.73%, 8.08%-10.04% and 5.19%-5.98% respectively for three chlorobenzenes compounds. CONCLUSION: The portable GC-MS could be used for qualitative and quantitative detection of three chlorobenzenes compounds in workplace air.
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OBJECTIVE: To improve the standard detection method for acetonitrile in workplace air. METHODS: Acetonitrile in the air of workplace was collected by silica gel, eluted with methanol, separated and determined by gas chromatography with flame ionization detection. RESULTS: After the improvement of the method, the linear range of acetonitrile was 1.57-1 574.00 mg/L, and the correlation coefficient was 0.999 98. The detection limit was 0.29 mg/L and the minimum detection concentration was 0.19 mg/m~(3 )(collected sample volume was 1.5 L). The average desorption efficiency was 93.1%-98.9%. The within-run and between-run precision was 2.6%-3.3% and 1.7%-3.6%, respectively. The samples could be stored at room temperature for at least 10 days. CONCLUSION: The improved method is precisied, accurate and simple to operate, which is suitable for determination of acetonitrile in workplace air.
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Objective To compare the pharmacological actions of Liandai Tablet(LT) and its main active components on apoptosis of gastric cancer cells and DNA damage. Methods Effects of Liandai Tablet(LT) and its main active components,berberine and indirubin,on growth and apoptosis of gastric cancer cell strain MGC_803 were explored and their effects on DNA damage were also studied. Results LT serum in high and low dosages and berberine could inhibit the growth of MGC_803 as compared with the control group,and typical morphological features of apoptosis were found in the MGC_803 by methyl green pyronin stain assay.But indirubin at various concentrations showed no obvious inhibitory effects. Agarose gel electrophoresis assay revealed that the MGC_803 cell DNA was split into large fragments when treated with berberine. Conclusion LT serum exerts a similar inhibitory effect on the growth and apoptosis of gastric cancer cells as compared with berberine.The effects of LT at various serum concentrations on MGC_803 DNA was less than that of berberine,and indirubin at the given concentration had no this effect.
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AIM To explore the effect of berberine in inhibition of proliferation and induction of apoptosis of gastric cancer cell MGC-803.METHODS The MGC-803 cell morphology and cell counting were studied by Trypan blue, MTT, Methyl green pyronin stain assay, the MGC-803 cell DNA changes were investigated by flow cytometry and agarose gel electrophoresis.RESULTS Berberine could significantly inhibit the growth of MGC-803. After 48 hours of treatment with different concentration berberine (8, 4, 2, 1 mg*L-1), the inhibitive rate of MGC-803 were 86.7%, 65.9%, 20.0%, 0%, respectively. Meanwhile, MGC-803 showed typical apoptosis features: cell shrinkage, nuclear condensation, DNA fragmentation and formation of apoptotic bodies. A typical subdiploid peak before G0/G1 phase was observed by flow cytometry. The Trypan blue stain achromatophilia rates of death cells, which with well membranes, were between 60%～82%. Agarose gel electrophoresis analysis, which showed that the chromosomes of MGC-803 were broken by berberine before the structures of membrane were damaged, while DNA broke into long fragments rather than small fragments, supported that the activation effect of berberine on nuclease was mild.CONCLUSION Berberine could significantly inhibit proliferation of gastric cancer cell MGC-803 and induced apoptosis, and the cytotoxicity of berberine on MGC-803 was weak.
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AIM To explore the effect of berberine in inhibition of proliferation and induction of apoptosis of gastric cancer cell MGC 803.METHODS The MGC 803 cell morphology and cell counting were studied by Trypan blue, MTT, Methyl green pyronin stain assay, the MGC 803 cell DNA changes were investigated by flow cytometry and agarose gel electrophoresis.RESULTS Berberine could significantly inhibit the growth of MGC 803. After 48 hours of treatment with different concentration berberine (8, 4, 2, 1 mg?L -1 ), the inhibitive rate of MGC 803 were 86 7%, 65 9%, 20 0%, 0%, respectively. Meanwhile, MGC 803 showed typical apoptosis features: cell shrinkage, nuclear condensation, DNA fragmentation and formation of apoptotic bodies. A typical subdiploid peak before G 0/G 1 phase was observed by flow cytometry. The Trypan blue stain achromatophilia rates of death cells, which with well membranes, were between 60%～82%. Agarose gel electrophoresis analysis, which showed that the chromosomes of MGC 803 were broken by berberine before the structures of membrane were damaged, while DNA broke into long fragments rather than small fragments, supported that the activation effect of berberine on nuclease was mild.CONCLUSION Berberine could significantly inhibit proliferation of gastric cancer cell MGC 803 and induced apoptosis, and the cytotoxicity of berberine on MGC 803 was weak.