HS-SPME-GC/MS测定饮用水中三卤甲烷分析条件的优化

对顶空固相微萃取 -气相色谱 /质谱联用测定饮用水中三卤甲烷的分析条件如固相微萃取的萃取时间、萃取温度、溶液的离子强度及 p H值等进行了优化。该方法的线性范围为 5— 15 0 μg/ L,相对标准偏差为 5 .4 %— 8.2 %。     

自制固相微萃取涂层测定水中的邻苯二甲酸酯

用溶胶-凝胶法制备的离子液体键合固相微萃取(SPME)涂层,采用顶空固相微萃取与气相色谱法(HS-SPME-GC)测定水中邻苯二甲酸酯(PAEs).优化了固相微萃取的实验条件.方法的检测限为0.0005-0.0500μg/L,线性范围在0.01-100μg/L.用该法测定了东湖水样、自来水及桶装水中PAEs的含量,邻苯二甲酸二丁酯的含量在1.10-3.10μg/L,其他3种未检出.东湖水样的加标回收率为81.0％-98.6％,相对标准偏差(RSD)为3.2％-9.2％.     

顶空固相微萃取气相色谱法快速测定人血中的五氯酚

将全自动顶空固相微萃取装置与气相色谱联用,建立了快速测定人血中五氯酚的新方法.实验优化了人血中五氯酚测定的顶空浓缩和固相微萃取各项技术参数,然后使用毛细管气相色谱法分离,电子捕获检测器定量测定.方法的线性范围为0.05-100μg/L,相关系数r=0.9997,检出限为0.02μg/L;加标回收率为86.7%-92.8...     

顶空固相微萃取法用于饮用水源水中苦味酸的间接测定

建立了间接测定饮用水源水中苦味酸的前处理方法——顶空固相微萃取法(HS-SPME)。用带65μm聚二甲基硅氧烷-二乙烯基苯(PDMS-DVB)涂层的固相微萃取柱顶空萃取水中苦味酸与次氯酸钠的反应产物——氯化苦(硝基三氯甲烷),氯化苦用气质联用仪检测,采用质谱的选择离子模式和内标法进行定量。实验优化了萃取条件,如萃取柱涂层、水样与次氯酸钠体积比例、样品体积、预反应时间、盐度、样品pH、反应和萃取的温度、萃取时间等。使用优化后的条件,获得方法检出限和校准曲线r分别为0.8μg/L和0.9950。线性范围2.0—20.0μg/L;饮用水源水加标回收率均值和相对标准偏差分别为106.5%和9.0%(n=6)。方法适用于饮用水源水中苦味酸的间接测定。     

基质固相分散高效液相色谱法检测河豚毒素

建立了河豚鱼肉中河豚毒素的基质固相分散萃取的提取方法,并采用高效液相色谱-二极管阵列检测器进行测定。通过样品前处理的优化,确立选取0.5g样品与2.0g阳离子交换(SCX)吸附剂混合研磨,并采用10mL 5%氨水:甲醇溶液(5:95,V/V)作为洗脱剂。经HPLC-PDA检测,结果表明,河豚毒素在1—100mg/L浓度范围内呈现良好的线性关系(R2=0.9990),检出限为3.8ng,定量下限为12.7ng;加标回收率为77.9%—108.1%,RSD为2.23%—5.45%。该方法操作简单、耗时少,符合河豚毒素分析检测的要求。     

超声萃取-C_(18)柱净化-GC/MS法测定土壤中邻苯二甲酸酯类污染物

采用超声波辅助萃取-非极性C18固相萃取小柱净化-GC/MS技术,测定了土壤样品中6种邻苯二甲酸酯类污染物;对最佳溶剂萃取条件和最佳净化条件进行了优化;在最佳实验条件下,方法的相对标准偏差在6.5%—10.6%之间,最低检出限在0.005—0.049mg/kg之间,实际土样加标回收率在73.9%—105.4%之间。     

分散液液微萃取-分光光度法测定环境水样中孔雀石绿

建立了简便、快速、有效的分散液液微萃取-分光光度法测定环境水样中孔雀石绿的分析方法。对萃取剂、分散剂的种类和体积、萃取时间、离心时间、盐浓度等影响萃取效率的因素进行了优化。在优化的萃取条件下,方法的线性范围为8—1000μg/L（r=0.9992）,相对标准偏差（RSD）为4.1%（C=100μg/L,n=6）,检出限为4.20μg/L。对3种实际水样中的孔雀石绿进行测定,加标回收率在74.7%—108.2%之间（n=5）。方法适用于环境水样中的痕量孔雀石绿的检测。     

固相微萃取-GC-MS-SIM法监测惠州市地表水中MTBE的污染状况

采用固相微萃取(SPME)-顶空采样-气相色谱-质谱联用选择离子检测法(GC-MS-SIM)测定水中微量的甲基叔丁基醚.最优化实验条件为:使用75μm Carboxen/PDMS固相微萃取纤维,30℃搅拌条件下,加入20%氯化钠进行盐析.检出限为0.05μg/L,相对标准偏差为2.75%(n=8),重现性较好,样品的加标回收率在82%-120%之间.对惠州市市区地表水中MTBE的污染状况进行了监测,结果表明惠州市汽油油罐附近地表水中MTBE含量未超过美国环保局(EPA)规定最低限,居民区地表水中MTBE含量未检出,符合环保和健康要求.     

顶空固相微萃取-气相色谱联用法测定工业废水中的致癌芳香胺

研究了使用固相微萃取聚二甲基硅氧烷/对乙烯基苯(Polydimethylsiloxane/Divinylbenzene,PDMS/DVB)纤维头顶空萃取方式与气相色谱-氢火焰检测器联用技术测定工业废水中的痕量邻甲苯胺。讨论了萃取纤维头的极性,萃取方式及时间,水溶液的酸度及盐效应和气相色谱解吸时间等因素对萃取率的影响,确定了固相微萃取的最佳条件,得到邻甲苯胺在水中的浓度在0.1—0.8mg/L之间有良好的线性关系,R2=0.9990,回收率为83.5%—87.3%,并成功地用于工业废水中邻甲苯胺的测定。     

固相萃取-气相色谱-质谱法测定水中的19种多氯联苯

建立了固相萃取-气相色谱-质谱联用选择离子扫描法同时检测水样中19种多氯联苯(PCB s)的方法。该法对水样中PCB s的检测具有较高的灵敏度和较好的线性,其相关性r≥0.9970,检出限为2.34—7.33ng/L、回收率为82.3%—103.2%,适用于水样中多氯联苯的测定。     

浊点萃取-石墨炉原子吸收法测定高盐样品中的痕量铅

在pH 6～7的缓冲体系中,样品溶液中的痕量铅与加入的吡咯烷二硫代氨基甲酸铵(APDC)为络合剂形成稳定的配合物。通过70 ℃恒温水浴3 h,铅配合物被萃取到表面活性剂相并与水相分开。 分离后的表面活性剂相室温就可配成上机待测样液。 此法不但将大量基体离弃在水相,从而消除高盐带来的高背景信号干扰,并将水样或1%食盐溶液的痕量铅富集10～100倍。用氘灯校正背景石墨炉原子吸收法进行测定,方法检出限：食盐0.000 5 μg·g-1,水样0.01 μg·L-1。回收率为92.3%～104%。用于食盐、海水、井水中痕量铅的测定,结果令人满意。     

正交试验优选断血流软胶囊提取工艺

以醉鱼草皂苷Ⅳb含量、断血流总皂苷含量和浸膏得率为考察指标,采用正交试验设计优选断血流软胶囊的提取工艺。最佳提取工艺为药材粒度为中粉,10倍量水,煎煮2次,每次1.0h,优选得到的工艺稳定、合理、可行。     

浊点萃取-火焰原子吸收光谱法测定微量铜

本文研究了浊点萃取 -火焰原子吸收光谱法测定微量铜。利用表面活性剂浊点特性实现胶束相分离 /富集微量待测离子。探讨了影响浊点萃取的因素。该方法用于自来水、河水及标准土壤中痕量铜的测定 ,具有低毒、高效、安全、简便等特点。     

Vortex-Assisted Acid-Induced Cloud Point Extraction Coupled With Spectrofluorometry for the Determination of Fluoroquinolones in Environmental Water Samples

The present work describes a simple and rapid extraction approach based on vortex-assisted acid-induced anionic surfactant sodium dodecyl sulfate-mediated extraction (vortex-assisted acid-induced cloud point extraction) prior to spectrofluorometry for the determination of four fluoroquinolones, including norfloxacin, ciprofloxacin, sarafloxacin, and gatifloxacin, in water samples (hospital wastewater, river water, lake water, and water from the inlet of a wastewater treatment plant). Sodium dodecyl sulfate and concentrated hydrochloric acid (12 mol/L) were used as extractants. The four fluoroquinolones were concentrated in the surfactant-rich phase after phase separation and were determined by a spectrofluorophotometer. Some parameters affecting the extraction efficiency, such as the type and amount of surfactant, the amount of acid, vortex treatment, and centrifugation, were optimized systematically. Under the optimized conditions, the proposed method showed good analytical features with linearity for all analytes in a wide range of 0.045–0.90 µg/mL and coefficients of determination no less than 0.9901. The limits of detection (S/N = 3) were 0.007, 0.010, 0.009, and 0.013 µg/mL for norfloxacin, ciprofloxacin, sarafloxacin, and gatifloxacin, respectively; good precisions expressed as the relative standard deviations were in the range of 0.9–3.7% (n = 6); and average recoveries at three spiking levels ranged from 83.0% to 96.7%. The results of the proposed method are comparable to those obtained from the high-performance liquid chromatography method (t-test, p = 0.05) and are reliable for determination of fluoroquinolones in environmental water samples.     

超声波辅助溶剂萃取-电感耦合等离子体质谱法测定生物样品中的总汞和甲基汞

建立了超声波辅助溶剂萃取联用电感耦合等离子体质谱法(ICP-MS)测定生物样品中总汞(T-Hg)和甲基汞(MeHg)的分析方法。实验优化了萃取溶剂种类,溶剂浓度,各种辅助方法和超声波振荡时间等各种萃取条件。选择6 mol·L-1 HCl作为溶剂,超声2 h, 以有机溶剂萃取,再以水反萃,稀释后直接进行测量MeHg的含量。此方法可用于同时测定T-Hg和MeHg, 检出限为0.01 ng·mL-1,相对标准偏差为3.44％,线性范围为1～50 ng·mL-1,加标回收率为80%～97%。在此条件下测定了5种不同类型生物标准参考物质的T-Hg和MeHg,测定值与标准值吻合。该法综合了超声波辅助萃取和溶剂微萃取以及ICP-MS的优点,操作简便快速,灵敏度高,适合于各种生物样品中痕量MeHg快速萃取分离和分析。     

Bio-refinery of orange peels waste: A new concept based on integrated green and solvent free extraction processes using ultrasound and microwave techniques to obtain essential oil,polyphenols and pectin

In this study, extraction of essential oil, polyphenols and pectin from orange peel has been optimized using microwave and ultrasound technology without adding any solvent but only “in situ” water which was recycled and used as solvent. The essential oil extraction performed by Microwave Hydrodiffusion and Gravity (MHG) was optimized and compared to steam distillation extraction (SD). No significant changes in yield were noticed: 4.22 ± 0.03% and 4.16 ± 0.05% for MHG and SD, respectively. After extraction of essential oil, residual water of plant obtained after MHG extraction was used as solvent for polyphenols and pectin extraction from MHG residues. Polyphenols extraction was performed by ultrasound-assisted extraction (UAE) and conventional extraction (CE). Response surface methodology (RSM) using central composite designs (CCD) approach was launched to investigate the influence of process variables on the ultrasound-assisted extraction (UAE). The statistical analysis revealed that the optimized conditions of ultrasound power and temperature were 0.956 W/cm² and 59.83 °C giving a polyphenol yield of 50.02 mg GA/100 g dm. Compared with the conventional extraction (CE), the UAE gave an increase of 30% in TPC yield. Pectin was extracted by conventional and microwave assisted extraction. This technique gives a maximal yield of 24.2% for microwave power of 500 W in only 3 min whereas conventional extraction gives 18.32% in 120 min. Combination of microwave, ultrasound and the recycled “in situ” water of citrus peels allow us to obtain high added values compounds in shorter time and managed to make a closed loop using only natural resources provided by the plant which makes the whole process intensified in term of time and energy saving, cleanliness and reduced waste water.     

正交试验优选老鹳草中没食子酸的提取工艺

以没食子酸含量和出膏率的综合评分为指标,以溶剂用量、提取时间和提取次数为考察因素,采用正交试验优选老鹳草中没食子酸的提取工艺。结果表明,最佳提取工艺为8倍量水、回流提取3次,每次60m in。该工艺稳定可行,可作为老鹳草中没食子酸的提取方法。     

Optimization of two methods based on ultrasound energy as alternative to European standards for soluble salts extraction from building materials

The Italian recommendation NORMAL 13/83, later replaced by the UNI 11087/2003 norm, were used as standard for soluble salts extraction from construction materials. These standards are based on long-time stirring (72 and 2h, respectively) of the sample in deionized water. In this work two ultrasound based methods were optimized in order to reduce the extraction time while efficiency is improved. The instrumental variables involved in the extraction assisted by ultrasound bath and focused ultrasounds were optimized by experimental design. As long as it was possible, the same non-instrumental parameters values as those of standard methods were used in order to compare the results obtained on a mortar sample showing a black crust by the standards and the optimized methods. The optimal extraction time for the ultrasounds bath was found to be of two hours. Although the extraction time was equal to the standard UNI 11087/2003, the obtained extraction recovery was improved up to 119%. The focused ultrasound system achieved also better recoveries (up to 106%) depending on the analyte in 1h treatment time. The repeatabilities of the proposed ultrasound based methods were comparables to those of the standards. Therefore, the selection of one or the other of the ultrasound based methods will depend on topics such as laboratory facilities or number of samples, and not in aspects related with their quality parameters.     

Ultrasound-assisted extraction of resveratrol from functional foods: Cookies and jams

Rapid extraction techniques with ultrasonic systems have been established to extract resveratrol from two functional foods, namely cookies and jams. The ultrasound-assisted extraction (UAE) was optimized using a full factorial design with three variables: solvent composition (10–70% and 30–90% methanol in water for cookies and jams, respectively), solvent-to-solid ratio (10:1–40:1), and ultrasonic probe diameter (2 and 7 mm). The extraction kinetics (5–30 min) were studied to confirm the full recovery of resveratrol from the functional foods. The resveratrol was quantified by Ultrahigh Performance Liquid Chromatography with a Fluorescense Detector (UPLC-FD).     

Ultrasonically extracted β-d-glucan from artificially cultivated mushroom,characteristic properties and antioxidant activity

Ganoderma mushroom cultivated recently in Malaysia to produce chemically different nutritional fibers has attracted the attention of the local market. The extraction methods, molecular weight and degree of branching of (1-3; 1-6)-β-d-glucan polysaccharides is of prime importance to determine its antioxidant bioactivity. Therefore three extraction methods i.e. hot water extraction (HWE), soxhlet extraction (SE) and ultrasound assisted extraction (US) were employed to study the total content of (1-3; 1-6)-β-d-glucans, degree of branching, structural characteristics, monosaccharides composition, as well as the total yield of polysaccharides that could be obtained from the artificially cultivated Ganoderma. The physical characteristics by HPAEC-PAD, HPGPC and FTIR, as well as the antioxidant in vitro assays of DPPH scavenging activity and ferric reducing power (FRAP) indicated that (1-3; 1-6)-β-d-glucans of Malaysian mushroom have better antioxidant activity, higher molecular weight and optimal degree of branching when extracted by US in comparison with conventional methods.