Preparation of activated carbons and their adsorption properties for greenhouse gases: CH4 and CO2

Three kinds of activated carbons were prepared using coconut-shells as carbon precursors and characterized by XRD, FT-IR and texture property test. The results indicate that the prepared activated carbons were mainly amorphous and only a few impurity groups were adsorbed on their surfaces. The texture property test reveals that the activated carbons displayed different texture properties, especially the micropore size distribution. The adsorption capacities of the activated carbons were investigated by adsorbing CH4, CO2, N2 and O2 at 25 ?C in the pressure range of 0-200 kPa. The results reveal that all the activated carbons had high CO2 adsorption capacity, one of which had the highest CO2 adsorption value of 2.55 mmol/g at 200 kPa. And the highest adsorption capacity for CH4 of the activated carbons can reach 1.93 mmol/g at 200 kPa. In the pressure range of 0-200 kPa, the adsorption capacities for N2 and O2 were increased linearly with the change of pressure and K-AC is an excellent adsorbent towards the adsorption separation of greenhouse gases.     

理想量子气体的尺度效应

根据欧拉-麦克劳林(Euler-MacLaurin)公式,导出有限理想量子气体的热力学量表达式,揭示系统尺度和边界形状对其性质的影响.结果表明,有限尺度效应导致了一系列与热力学极限条件下不同的性质特征,如系统的非广延性和压强的各向异性等.     

固相萃取-气相色谱-串联质谱法同时测定武汉市普通人群血清中35种有机氯农药与多氯联苯

有机氯农药(OCPs)和多氯联苯(PCBs)是两类重要的持久性有机污染物,可在环境介质中长期存在,并通过多种途径进入人体,导致人体的高暴露风险。OCPs和PCBs对人体存在诸多健康危害,精准定量人体内OCPs和PCBs的暴露水平是健康效应评价的关键。该研究基于固相萃取-气相色谱-串联质谱联用技术(SPE-GC-MS/MS)建立了同时检测100 μL血清中35种OCPs和PCBs的分析方法。血清样品经尿素沉淀蛋白后,采用Oasis^® HLB小柱净化,正己烷-二氯甲烷混合溶液(1∶1, v/v)洗脱,氮吹近干,正己烷定容,多反应监测(MRM)模式检测,内标法定量分析。结果表明,OCPs和PCBs在0.05~50.0 ng/mL范围内线性关系良好,检出限在1.2~71.4 ng/L之间。35种目标分析物的加标回收率在72.6%~142%之间,相对标准偏差小于25%。利用所建立的方法检测了武汉市普通人群血清样本中OCPs和PCBs的浓度水平,结果表明武汉市普通人群广泛暴露于OCPs和PCBs,且以OCPs为主。有8种OCPs和7种PCBs检出率高于50%,其中p,p'-滴滴伊、p,p'-滴滴滴和甲氧滴滴涕检出率达100%,非类二噁英PCBs是PCBs的主要成分。血清中OCPs浓度随年龄增长呈升高趋势,在60岁以上存在性别差异;不同性别、年龄人群血清中PCBs浓度无统计学差异。该方法样本用量少,操作简便,具有较高的准确度和精密度,适用于环境健康研究中大量人群血清样本中痕量OCPs和PCBs的生物监测。     

气相色谱-负化学源质谱法测定船舶压载水中4种三卤甲烷北大核心CSCD

我国每年的船舶压载水排放量巨大,压载水中含有浮游生物、病原体及其幼虫或孢子等,若处理不当,会对排放水域的生态环境造成严重影响。排放压载水前常使用电解法对其进行处理,电解产生的次氯酸钠溶液,能有效杀灭残余的微生物。但电解后会产生副产物三卤甲烷(THMs),其对人体有一定的健康风险,建立船舶压载水中三卤甲烷的测定方法具有重要意义。该研究建立了采用气相色谱-负化学源质谱(GC-NCI-MS)测定船舶压载水中4种三卤甲烷(包括三氯甲烷、二氯一溴甲烷、一氯二溴甲烷、三溴甲烷)的分析方法。船舶压载水样品经过顶空进样技术处理后,通过DB-5MS UI毛细管色谱柱(30 m×0.25 mm×1.0μm)分离,气相色谱-负化学源质谱仪测定,在选择离子扫描(SIM)模式下分析,采用外标法进行定量。4种三卤甲烷在0.2~50μg/L范围内线性关系良好,相关系数(r)≥0.995,定量限(S/N=10)为0.1~0.2μg/L,在0.2、0.5、2.0μg/L 3个加标水平下,4种THMs的平均回收率为90.3%~106.8%,相对标准偏差(RSD)为1.4%~6.2%。该方法准确、稳定、可靠,可用于测定船舶压载水中4种THMs的含量。使用建立的测定方法对36个船舶压载水进行测定,三溴甲烷、二溴一氯甲烷、一溴二氯甲烷与三氯甲烷的检出率分别为83.3%、69.4%、22.2%和19.4%,检出值分别为34.25~221.5μg/L、3.52~41.87μg/L、1.52~8.56μg/L和0.02~5.46μg/L。     

The impact of insecticides containing deltamethrin and cyfluthrin on the composition of surface compounds in the larvae,females and males of Tenebrio molitor

This paper presents the effect of insecticides on the composition of the surface compounds of one of the most harmful insects, Tenebrio molitor, by analysis using GC–MS. As a result of the use of insecticides, the composition of the chemical compounds on the surface of insects changes, depending on the insecticides used. The most numerous groups of the marked compounds were fatty acids, alkanes, esters and sterols. The content of the identified compounds in the larvae increased at both 24 and 48 h after the application of insecticides, in comparison with the control samples. The content of identified compounds in the samples taken from the females increased 24, 48 and 72 h after the application of insecticides in comparison with the control samples. By contrast, in samples prepared from males, the content of identified compounds decreased 24 h after the application of insecticides, compared with the control samples. The highest content of chemical compounds was for fatty acids and alkanes after the use of insecticides. The content of fatty acids after the application of the insecticide with deltamethrin was 62.1 ± 3.3–466.9 ± 5.9 μg/g, and after the application of the insecticide with cyfluthrin was 49.9 ± 1.9–458.3 ± 4.2 μg/g. However, the content of alkanes after the use of deltamethrin was 115.6 ± 4.2–4672.0 ± 32.1 μg/g, and after the use of cyfluthrin was 189.4 ± 3.8–3975.0 ± 10.2 μg/g.     

Trace-level analysis of polychlorinated biphenyls,organochlorine pesticides and polycyclic aromatic hydrocarbons in human plasma or serum by dispersive liquid–liquid microextraction and gas chromatography–tandem mass spectrometry

A method to determine 8 polychlorinated biphenyls (PCBs), 23 organochlorine pesticides (OCPs) and 16 polycyclic aromatic hydrocarbons (PAHs) was described using dispersive liquid–liquid microextraction (DLLME) of a small amount of plasma or serum sample and gas chromatography–tandem mass spectrometry (GC–MS/MS). The appropriate selection of the extraction solvent and dispersing solvent contributes to a high extraction yield and a clean extract. To verify the developed method, the interference, linearity of the calibration curve, detection limit, precision and accuracy were evaluated. The calibration curves were linear by 2–3 orders of magnitude with correlation coefficients above 0.997 in all cases. The LODs of PCBs, OCPs and PAHs were measured in the ranges of 0.0006–0.0029, 0.001–0.029 and 0.0002–0.012 ng/mL. The intraday precision achieved by this method was 2.19–10.3% (PCBs), 1.65–14.3% (OCPs) and 0.91–12.8% (PAHs), and the intraday accuracy 1.56–7.37% (PCBs), 2.34–19.6% (OCPs) and 1.49–15.7% (PAHs). The advantage of this method is that the analysis of PCBs, OCPs, and PAHs can be performed in a single chromatographic run, and the low detection limit enables monitoring of target substances in low exposure general public samples, and the analysis procedure is relatively simple and fast.