OBJECTIVE: To study antimicrobial activity of petroleum ether,chloroform,ethyl acetate and n-butanol extracts from Dracontomelon duperreanum.METHODS: The disk diffusion method was applied for antimicrobial activity.RESULTS: The ethyl acetate extracts showed the strongest activity against Staphylococcus aureus,Escherichia coli,Bacillus subtilis with minimal inhibitory concentration (MIC) of 0.117～0.234 mg/disc,followed by n-butanol extracts with MIC of 0.496 mg/ disc .CONCLUSION: Ant- imicrobial activity of ethyl acetate extract from D.duperreanum is superior to other extracts,which can provide theoretical basis for further development of D.duperreanum.

Abstract： Objective　To analyze the epidemic situation and risk factors of schistosomiasis in Hubei Province from 2015 to 2022, and to provide a scientific basis for the goal of all schistosomiasis-endemic counties in the province reaching the elimination standard by 2030. Methods　According to the requirements of the National Schistosomiasis Surveillance Plan (2014 edition) and National Schistosomiasis Surveillance Plan (2020 edition), the snail situation and the risk of wild fecal transmission, along with regional distribution in schistosomiasis endemic areas in Hubei Province from 2015 to 2022 were analyzed and the risk was rated. Results　From 2015 to 2022, a total of 60 203 risk monitoring environments per time was carried out, with 10 223 460 frames of snails inspected, capturing 2 344 094 snails, among which 1 357 479 live snails, and an average density ranging from 0.07-0.29 snails/0.11 m2. In 2015 and 2017, 11 and 3 schistosomiasis-infected snails were detected respectively, corresponding to 3 and 2 positive snail environments. The proportion of wild feces distribution environment in the total monitoring environment showed a downward trend, with cow dung accounting for the highest proportion (69.27%). A total of 19 549 wild feces were collected, of which 78 were positive for schistosomiasis. Since 2018, only one positive cow dung was found in 2019, and none in other years. From 2015 to 2020, the density of live snails and the proportion of wild feces in the monitoring environment in each risk monitoring county (city, district) had significantly reduced, with areas of higher snail density such as Gongan County, Yangxin County with higher density of live snails decreasing to below 1 per 0.11 m2 from 2017. Among the 60 203 risk monitoring environments, 53 were identified as GradeⅠrisk (not detected since 2020), 1 999 as GradeⅡrisk, and 58 030 as GradeⅢrisk. Conclusions　From 2015 to 2022, the overall schistosomiasis epidemic in Hubei Province showed a downward trend. However, the risk of schistosomiasis transmission still exists in some areas. In the future, we should continue to strengthen the epidemic monitoring in key areas, improve the sensitivity and level of monitoring, and prevent the rebound of the epidemic.

Objective:To establish a method for determining methoxyacetic acid in urine by pre-column derivatization-liquid-liquid microextraction coupled with gas chromatography (GC) .Methods:Phosphate buffer solution, tert-butoxyacetic acid (internal standard) and pentafluorobenzyl bromide (derivative) were added to the urine sample. After derived in a water bath at 90 ℃ for 40 min, the mixture was cooled and filtered, then the dichloromethane was used as an extractant. After being shaken and centrifuged, the lower organic phase was sucked and injected into a gas chromatograph, separated by a DB-5 capillary column, and detected by an ECD detector.Results:The linear range of the method was 0.6~60.0 mg/L with the correlation coefficients ( r) above 0.999. The average recovery was76.6%~110.7%, the inter-day precision was 8.00%~8.82%, and the detection limit was 0.13 mg/L. Conclusion:The method was founded to be high sensitivity, low organic reagent usage and green. So it is suitable for the detection of methoxyacetic acid in urine of occupational exposure to ethylene glycol monomethyl ether.

Objective:To establish a method for determining methoxyacetic acid in urine by pre-column derivatization-liquid-liquid microextraction coupled with gas chromatography (GC) .Methods:Phosphate buffer solution, tert-butoxyacetic acid (internal standard) and pentafluorobenzyl bromide (derivative) were added to the urine sample. After derived in a water bath at 90 ℃ for 40 min, the mixture was cooled and filtered, then the dichloromethane was used as an extractant. After being shaken and centrifuged, the lower organic phase was sucked and injected into a gas chromatograph, separated by a DB-5 capillary column, and detected by an ECD detector.Results:The linear range of the method was 0.6~60.0 mg/L with the correlation coefficients ( r) above 0.999. The average recovery was76.6%~110.7%, the inter-day precision was 8.00%~8.82%, and the detection limit was 0.13 mg/L. Conclusion:The method was founded to be high sensitivity, low organic reagent usage and green. So it is suitable for the detection of methoxyacetic acid in urine of occupational exposure to ethylene glycol monomethyl ether.

Objective: To establish a method for determining cyclohexanol in urine by headspace solid-phase microextraction (HS/SPME) coupled with gas chromatography (GC) . Methods: After the urine sample was hydrolyzed by β-glucuronidase, 2.0 g of NaCl was added, then the analyte in urine was adsorbed by a CAR/PDMS solid phase micro-extraction head in a water bath at 50 ℃ for 20 min. And the extraction head was inserted into the gas chromatograph gasification chamber to desorb, the analyte was detected after separated by the capillary through the flame ionization detector. Results: The linear range of the method was 0.1-5.0 mg/L with the correlation coefficients (r) 0.999. The average recovery was 84.5%-96.3%, the inter-day precision was 3.81%-6.00%, and the detection limit was 0.03 mg/L. Conclusion The method is founded to be low detection limit, simple operation and no need of organic solvent. So it is suitable for the detection of cyclohexanol in urine of occupational exposure to cyclohexanone.

Objective: To establish a method for the determination of 1-methoxy-2-propanol in urine using headspace solid phase micro-extraction coupled with gas chromatography. Methods: The 1-methoxy-2-propanol was enriched by headspace solid phase micro-extraction fiber coated with carbene/polydimethylsiloxane (CAR/PDMS) . Single factor rotation method was used to optimize the conditions of extraction temperature, salt amount, and extraction time. The separation was performed on DB-5 (30 m×0.32 mm×0.25 μm) capillary column and detected with flame ionization detector. The quantification was based on the standard curve. Results: The concentration of 1-methoxy-2-propanol in urine was linear in the range of 0.50-10.0 mg/L, and the linear correlation coefficient was 0.9993. The detection limit of the method was 0.14 mg/L, and the limit of quantification was 0.45 mg/L. The recovery was 85.8% to 104.7%, and the RSD of intra- and inter-batch precision were 3.25%-6.65% and 0.81%-3.96%, respectively. Conclusion The method is high sensitivity and simple operation, and is suitable for the determination of 1-methoxy-2-propanol in urine of occupational exposure population.

Objective:To establish a headspace solid phase microextraction-gas chromatography method for determination of n-Butyl alcohol in urine.Methods:In October 2019, the n-butyl alcohol in urine was extracted with a polydimethylsiloxane/divinylbenzene (PDMS/DVB) solid-phase microextraction head. The conditions of salt amount, extraction temperature, extraction time and desorption time were optimized. The separation was performed on HP-5 (30 m×0.32 mm×0.25 μm) capillary column and detected with flame ionization detector. The quantification was based on the external standard curve.Results:The linear relationship of n-butyl alcohol in urine was good in the range of 0.04-3.00 mg/L, the correlation coefficient was 0.999, the detection limit of the method was 0.04 mg/L, the recovery was 77.4%-102.8%, the intra-run precision was 3.67%-8.11%, and the inter-assay precision was 4.94%-6.90%.Conclusion:The method has simple operation, high concentration efficiency and high sensitivity, and it is suitable for the determination of n-butyl alcohol in urine of occupational exposure to n-butyl alcohol.

Objective:To establish a headspace solid phase microextraction-gas chromatography method for determination of n-Butyl alcohol in urine.Methods:In October 2019, the n-butyl alcohol in urine was extracted with a polydimethylsiloxane/divinylbenzene (PDMS/DVB) solid-phase microextraction head. The conditions of salt amount, extraction temperature, extraction time and desorption time were optimized. The separation was performed on HP-5 (30 m×0.32 mm×0.25 μm) capillary column and detected with flame ionization detector. The quantification was based on the external standard curve.Results:The linear relationship of n-butyl alcohol in urine was good in the range of 0.04-3.00 mg/L, the correlation coefficient was 0.999, the detection limit of the method was 0.04 mg/L, the recovery was 77.4%-102.8%, the intra-run precision was 3.67%-8.11%, and the inter-assay precision was 4.94%-6.90%.Conclusion:The method has simple operation, high concentration efficiency and high sensitivity, and it is suitable for the determination of n-butyl alcohol in urine of occupational exposure to n-butyl alcohol.

Objective:To establish a method for the determination of mandelic acid and phenylglyoxylic acid in the urine of styrene by dispersive liquid-liquid microextraction-high coupled with high performance liquid chromatography.Methods:N-octanol was used as an extractant and ethanol was used as a dispersing agent. The phenylglycolic acid and phenylglyoxylic acid in the urine were extracted, and the upper liquid was taken after vortexing and centrifuged, and then was injected into HPLC for analysis.Results:The linear correlation coefficient of the concentration of phenylglycolic acid in the range of 0~10.0 mg/L was greater than 0.999. The detection limit of the method was 9.9 μg/L, the recovery rates were 86.1%~101.6%. The intraday RSDs of the method were 1.07%~3.76%, and the interday RSDs were 1.24%~3.33%. The linear correlation coefficient of phenylglyoxylic acid in the range of 0.0~2.0 mg/L is greater than 0.999. The detection limit of the method was 2.6 μg/L, the recovery rates were 88.8%~100.3%. The intraday RSDs of the method were 1.02%~ 3.17%, and the interday RSDs were 1.59%~2.41%.Conclusion:The method has low detection limit, high enrichment ratio and good sensitivity, and is suitable for determination of phenylglycolic acid and phenylglyoxylic acid in urine of occupational exposure to styrene.

Objective:To establish a method for the determination of mandelic acid and phenylglyoxylic acid in the urine of styrene by dispersive liquid-liquid microextraction-high coupled with high performance liquid chromatography.Methods:N-octanol was used as an extractant and ethanol was used as a dispersing agent. The phenylglycolic acid and phenylglyoxylic acid in the urine were extracted, and the upper liquid was taken after vortexing and centrifuged, and then was injected into HPLC for analysis.Results:The linear correlation coefficient of the concentration of phenylglycolic acid in the range of 0~10.0 mg/L was greater than 0.999. The detection limit of the method was 9.9 μg/L, the recovery rates were 86.1%~101.6%. The intraday RSDs of the method were 1.07%~3.76%, and the interday RSDs were 1.24%~3.33%. The linear correlation coefficient of phenylglyoxylic acid in the range of 0.0~2.0 mg/L is greater than 0.999. The detection limit of the method was 2.6 μg/L, the recovery rates were 88.8%~100.3%. The intraday RSDs of the method were 1.02%~ 3.17%, and the interday RSDs were 1.59%~2.41%.Conclusion:The method has low detection limit, high enrichment ratio and good sensitivity, and is suitable for determination of phenylglycolic acid and phenylglyoxylic acid in urine of occupational exposure to styrene.