Liquid-liquid Microextraction Based on Solidification of Floating Organic Drops Coupled with Gas Chromatography for Analyzing Trace Benzene,Toluene and Xylene in Water Samples

A new liquid-liquid microextraction method based on the solidification of floating organic drops coupled with gas chromatography was developed for the determination of trace benzene, toluene and xylene(BTX) in water samples. In the microextraction procedure, a microdrop of n-decanol was delivered to the surface of the analytes’ solution, and stirred for a desired time. Following the absolute extraction, the sample vial was cooled in an ice bath for 10 min. The solidified n-decanol was then transferred into a plastic tube and melted naturally; and 1 μL of it was injected into gas chromatography for analysis. Factors relevant to the extraction efficiency were studied and optimized. The optimal experimental conditions were: 15 μL of n-decanol as extractive solvent, 30 mL of solution containing analytes, no salt, the stirring rate 400 r/min, the extraction temperature 30 °C, and the extraction time 30 min. Under those optimized conditions, the detection limit(LOD) of analytes was in a range of 0.05―0.10 ng/mL by the developed method. A good linearity(r>0.99) in a calibration range of 0.01―100 μg/mL was obtained. The recoveries of the real samples at different spiked levels of BTX were in the range from 92.2% to 103.4%.     

LED照射光催化剂用于苯、甲苯、乙苯和二甲苯分解(英文)

Studies on the use of gas phase applications of light emitting diodes(LEDs) in photocatalysis are scarce although their photocatalytic decomposition kinetics of environmental pollutants are likely different from those in aqueous solutions.The present study evaluated the use of chips of visible light LEDs to irradiate nitrogen doped titania(N-TiO2) prepared by hydrolysis to decompose gaseous benzene,toluene,ethyl benzene,m-xylene,p-xylene,and o-xylene.Photocatalysts calcined at different temperatures were characterized by various analytical instruments.The degradation efficiency of benzene was close to zero for all conditions.For the other compounds,a conventional 8 W daylight lamp/N-TiO2 unit gave a higher photocatalytic degradation efficiency as compared with that of visible-LED/N-TiO2 units.However,the ratios of degradation efficiency to electric power consumption were higher for the photocatalytic units that used two types of visible-LED lamps(blue and white LEDs).The highest degradation efficiency was observed with the use of a calcination temperature of 350 oC.The average degradation efficiencies for toluene,ethyl benzene,m-xylene,p-xylene,and o-xylene were 35%,68%,94%,and 93%,respectively.The use of blue-and white-LEDs,high light intensity,and low initial concentrations gave high photocatalytic activities for the photocatalytic units using visible-LEDs.The morphological and optical properties of the photocatalysts were correlated to explain the dependence of photocatalytic activity on calcination temperature.The results suggest that visible-LEDs are energy efficient light source for photocatalytic gas phase applications,but the activity depends on the operational conditions.     

胶束电动毛细管色谱法测定海洋沉积物中的苯、甲苯和二甲苯

 建立了用胶束电动毛细管色谱法（MECC）对海洋沉积物中的苯、甲苯和二甲苯进行 分析测定的方法 。用45 cm（到检测窗口40 cm）×75　μm i.d.毛细管柱,以75　mmol/L SDS-2　mmol/L 四硼酸钠溶液（外加体积分数为20%的甲醇）为缓冲液（pH 9.16）。当电压为25 kV、检测 波长为200 nm时,苯、甲苯和二甲苯在20 min内得到了良好的分离。用峰面积定量,线性范 围为4～50 mg/L,相对标准偏差在6.2%以内。测得海洋沉积物中的这些苯系物的质量比范围 为3.79～17.36 μg/g。     

Simultaneous Determination of Trace Benzene and Toluene in Beverage by Ultrasound-Enhanced Hollow-Fiber Liquid-Phase Microextraction Coupled with GC

This study describes an ultrasound-accelerated hollow-fiber liquid-phase microextraction (U-HF-LPME) method for the simultaneous trace analysis of benzene and toluene in beverages. Sample preparation was followed by analysis using gas chromatography–flame ionization detection. Experimental parameters such as extraction solvent, extraction time, ultrasonic power and frequency, extractant volume and ionic strength of the sample were assessed and optimized. Finally, the enrichment factor (EF), limit of quantitation (LOQ) and precision of the method for benzene and toluene were evaluated. The relative standard deviations (RSD, n = 5) were found to be 0.11 and 1.07% with good relative recovery of 98.2 and 99.6%, respectively. High EF of 105 and 308, and LOQ of 0.34 and 0.18 μg L^?1 were obtained within 10 min. The results demonstrated that the proposed method was suitable for trace analysis of beverage samples.     

活性碳纤维固相微萃取/气相-质谱联用测定水中苯系物

 对直接进样、二硫化碳萃取和活性碳纤维固相微萃取 (ACF SPME)分别与气相 质谱联用测定水中的苯系物的方法进行了比较研究。对 3种方法的线性、重复性、最小检出限等进行了试验测定。测定结果表明 ,固相微萃取在灵敏度方面优于其他方法 ,但在重复性方面还有待提高。利用固相微萃取方法进行了实际废水样的检测及回收率试验 ,结果令人较为满意。     

气相色谱法同时测定涂料中的苯系物和邻苯二甲酸酯类环境激素

建立了涂料中苯、甲苯、二甲苯异构体、邻苯二甲酸酯类化合物(DEP、DBP、BBP、DEHP、DNOP)多种有毒有害成分同时检测技术 ;用化学和吸附/脱附惰性膜除去样品中的大部分树脂成膜物质、颜填料及各种微粒助剂 ;用毛细管柱气相色谱分离 ,内标法定量 ;苯系物的线性范围为1×10-2～100μg,邻苯二甲酸酯类增韧剂为5×10-2～20μg;苯系物的回收率为97 %～103 % ,相对标准偏差 (RSD)的范围为0.12 %～0.95 % ;邻苯二甲酸酯类增韧剂的回收率为96 %～102 % ,相对标准偏差 (RSD)的范围为0.92 %～2.46 %。结果表明 :该方法简便、快速、灵敏、精密度好。     

Introducing Organic Gas Steam-Liquid Extraction as a New Preconcentration Method for Benzene,Toluene, Ethylbenzene and Xylene Determination in Water Samples by Gas Chromatography-Flame Ionization Detection

Journal of Analytical Chemistry - In this study, for the first time, the organic gas steam-liquid extraction by a special hand-made cell was used as a simple and inexpensive preconcentration...     

气相色谱内标法测定胶黏剂中的苯、甲苯、二甲苯

以气相色谱内标法测定胶黏剂中苯、甲苯、二甲苯,在试剂空白和样品组分不干扰内标物的情况下,5种目标物线性相关系数均达0.999 99;测定结果不受高黏度样品进样量的影响,相对标准偏差为0.06%~0.30%(n=9);在40~600 mg/L的3个浓度水平内,加标回收率在98.93%~100.98%之间。内标法测量精密度与准确度均优于外标法。     

毛细管气相色谱法测定腈纶布料中苯、甲苯和二甲基甲酰胺残留

 建立了同时定量测定腈纶布料及其服装中的苯、甲苯和二甲基甲酰胺残留的毛细管气相色谱分析方法。测得的回收率分别为 93 .3 % ,1 0 1 .8% ,94.9% ;变异系数为 3 .4% ,2 .0 % ,2 .8%。方法简便、快速、准确。     

环境水体中苯和甲苯的快速测定

本文用大口径毛细管柱和顶空进样技术对水体中苯和甲苯的测定条件进行了探讨。实验表明：本方法灵敏度高、检出限为5μg／L。样品处理简单，是日常分析中一种快速、简单的方法。     

三苯类废气污染及从业人员健康状况调查

为了开展国内精细化工产品生产使用中三苯(苯、甲苯、二甲苯)类废气排放和从业人员健康状况调查研究,为精细化工三苯类废气的治理提供政策依据和管理支持,促进精细化工行业的可持续发展,通过查阅大量相关文献资料,对国内相关企业三苯类废气的污染情况及从业人员健康状况进行调研。结果表明,所调研的皮具、地板、涂料、化工、陶瓷等行业都存在三苯类废气严重污染现象,对从业人员的健康也造成不同程度的损害,因此应加强对三苯类废气污染的治理工作。     

Graphene-modified Monolithic Capillary Column for the Microextraction of Trace Benzodiazepines in Biological Samples

A graphene monolithic column was fabricated in a capillary using π-electron-rich poly(N-vinylcarbazole-divinylbenzene) as the supporter through in situ one-step polymerization for the enrichment of trace benzodiazepines in biological samples. This new three-dimensional monolith showed uniformity and a continuous column bed; more importantly, it retained the unique properties of graphene that are typically associated with individual graphene sheets. Based on the large delocalized π-electron system, graphene forms π–π stacking interactions with benzodiazepines and benzene rings of poly(N-vinylcarbazole-divinylbenzene), which not only enhance the extraction performance for benzodiazepines compared to the neat polymer but also provide chemical stability of the graphene monolith. Moreover, several factors likely to affect the extraction, including ionic strength, sample pH, sample volume, and eluant volume were studied in detail. The optimized method gave a linear range of 0.005–1?ng?mL^?1, and detection limits of 1.12–2.35?ng?L^?1. Finally, the graphene monolith was successfully applied to the separation and enrichment of benzodiazepines from urine and hair samples coupled with high-performance liquid chromatography–mass spectrometry. The recoveries were in the range of 78.6–85.6% for urine and 87.2–94.3% for hair with relative standard deviations of 3.4–6.9 and 2.9–8.3%, respectively.     

Comparison of SPE-TD-GC-FID with UPLC-PDA and GC-MS Methods for Analysis of Benzene, Toluene and Xylene Isomers in Solid-Liquid Mixing Paints

Three methods were developed for analysis of benzene, toluene, p-xylene, m-xylene and o-xylene (BTX) in a solid-liquid mixing paint. These methods were based on solid phase extraction-thermal desorption-gas chromatography with a flame ionization detector (SPE-TD-GC-FID), ultra performance liquid chromatography-photodiode array detector (UPLC-PDA) and gas chromatography-mass spectrometry (GC-MS). At their optimum conditions of operation, the developed methods were compared in terms of recovery, sensitivity, selectivity and universality. Although the time required for GC-MS analysis was shorter than for GC-FID and UPLC-PDA, it offered relatively poorer recoveries and suffered from matrix interferences. All of the mentioned methods were proven to be ideal for the analysis of targeted analytes; SPE-TD-GC-FID was particularly fit for the determination of trace level BTX residues present in the complex matrix. As one of the sample pretreatment techniques, the novel SPE also showed some selectivity towards BTX and was found to be superior to the conventional SPE.     

离子液体单滴微萃取-高效液相色谱法测定水体中磺胺类药物

应用离子液体单滴微萃取(SDME)技术,建立了水体中7种磺胺类药物的高效液相色谱(HPLC)分析方法.考察了萃取剂种类与体积、萃取时间、搅拌速度、溶液pH值、盐浓度及萃取温度对萃取效率的影响.确定了最佳萃取条件为:利用9 μL-丁基-3-甲基咪唑六氟磷酸盐([C<,4MIM][PF<,6])离子液体作为萃取液滴,在搅拌...     

凝固-漂浮分散液液微萃取富集分光光度法测定水中亚硝酸根

研究了凝固-漂浮分散液液微萃取（SFO-DLLME）-分光光度法测定水样中痕量亚硝酸根的方法。以1-十二醇为萃取剂,乙醇为分散剂进行分散液液微萃取,离心后通过冷冻凝固操作使漂浮的萃取剂和水相分离。最佳实验条件下,方法的线性范围为2.0-280μg/L（r=0.999 9）,检出限为0.34μg/L。方法已成功应用于环境水样分析,相对标准偏差在2.4%-3.3%,加标回收率在98.2%-102.4%。     

顶空液相微萃取-气相色谱质谱法快速测定饮料中苯和甲苯

建立了顶空液相微萃取-气相色谱质谱法测定饮料中苯和甲苯的方法。在对顶空液相微萃取(head-space liquid-phase microextraction,HS-LPME)实验条件优化的基础上,确定了最佳实验条件:以1.6μL正辛醇作为有机萃取剂,在萃取温度为50℃、萃取时间为5min,搅拌速度为750r/min,液滴离萃取瓶瓶塞2.0cm的条件下,萃取4.00mLNaCl含量为4.00mol/L的样品水溶液,取0.4μL的有机萃取剂直接进样。实验结果表明,苯和甲苯的富集倍数分别为94和191,方法检出限分别为0.090μg/L和0.093μg/L,线性范围为0.5～60μg/L(r>0.999)。将该方法应用于饮料中苯和甲苯的测定,回收率为93.6%和98.0%,相对标准偏差(RSD)为3.94%和2.69%。方法简单、快速且成本低、可信度高,适用于饮料和水样中苯和甲苯的快速分析。     

固相萃取-分散液液微萃取-柱前衍生法测定水样中痕量雌激素

建立了碳纳米管的固相萃取-分散液液微萃取-柱前荧光衍生化(SPE-DLLME-PFD)测定水体中痕量雌三醇(E3)、双酚A(BPA)、17α-乙炔基雌二醇(EE2)及17β-雌二醇(E2)的高效液相色谱方法.采用中心复合设计和响应曲面法分析并优化SPE、DLLME及PLD条件,最佳条件为210 mL水样以2.0 mL/min的流速过固相萃取柱(碳纳米管量30 mg),甲醇洗脱,氮气浓缩并定容至0.6 mL(分散剂),将100 μL C6MIM[PF6]与分散剂的混合液注入到NaCl含量为25％的2.0 mL去离子水中,离心,移取20 μL下层有机相于样品瓶中,与4.0 mg衍生剂混合,在40℃水浴中衍生25 min;用0.1mL甲醇溶解过量的衍生剂颗粒,取20 μL进样分析.在优化条件下.4种雌激素的线性范围为0.05～5.00 μg/L,相关系数R2=0.9966～0.9999;,检出限介于0.13～6.33 ng/L(S/N=3)之间.不同加标浓度条件下,雌激素的加标回收率在83.1％～122.4％范围内(RSD=1.7％～9.6％).在实际水样中E3和BPA检出率较高.与其它方法相比,本方法虽然萃取时间长、水样量大、步骤多,但具有检出限低、操作简便、环境友好等优点.     

溶剂萃取-火焰原子吸收法测定自来水中微量钴

以硫氰酸根离子为配位阴离子,甲基异丙酮为萃取剂萃取自来水中微量钴,将有机相加热蒸发萃取剂后,置于550℃高温炉中干法灰化,灰化后,加盐酸微热使残渣溶解,然后用火焰原子吸收光谱法测定钴。该法提高了灵敏度,回收率为95.0%~102.5%,相对标准偏差为1.58%~4.92%,检出限为0.014 mg/L。     

Development of Dispersive Liquid‐Liquid Microextraction Based on Solidification of Floating Organic Drop for the Determination of Trace Cobalt in Water Samples

A liquid‐phase microextraction technique was developed using dispersive liquid‐liquid microextraction based on solidification of floating organic drop combined with flame atomic absorption spectrometry, for the extraction and determination of trace amounts of cobalt in water samples. Microextraction efficiency factors, such as the type and volume of extraction and dispersive solvents, pH, extraction time, the chelating agent amount, and ionic strength were investigated and optimized. Under optimum conditions, an enrichment factor of 160 was obtained from 10.0 mL of water sample. The calibration graph was linearin the range of 1.15‐110 μg L^?1 with a detection limit of 0.35 μg L^?1. The relative standard deviation for ten replicate measurements of 10 and 100 μg L^?1 of cobalt were 3.26% and 2.57%, respectively. The proposed method was assessed through the analysis of certified reference water or recovery experiments.     

固相微萃取-毛细管气相色谱法测定污染棕榈油中的低浓度二甲苯

采用一种新型的样品制备技术－固相微萃取代替传统的顶空进样技术,结合毛细管气相色谱,快速,灵敏地检测出污染进口棕榈油的低浓度的二甲苯。以苯为内标,以大豆油模拟基质制作标准曲线。在０．２￣２０ｍｇ／ｋｇ浓度范围内呈线性,对样品和标样萃取的精度良好。