固相微萃取法同时分析源水中54种挥发性有机物

建立了同时测定饮用水源水中54种挥发性有机物的前处理方法———顶空固相微萃取法。用65μm聚二甲基硅氧烷二乙烯基苯(PDMS-DVB)固相微萃取柱顶空萃取水样中的挥发性有机物,萃取物用气相色谱/质谱联用法(GC-MS)分析,采用质谱(MS)检测器的选择离子监测模式(SIM)和内标法进行定量分析。试验优化了顶空固相微萃取条件,如萃取柱涂层、盐度、萃取温度和萃取时间等。采用优化后的条件获得的方法检出限为0.01～0.37μg/L,在所测浓度范围内校准曲线的相关系数良好(除三氯甲烷和四氯化碳外均大于0.991),对0.60μg/L标准水样测得结果的RSD均小于15%;实际饮用水源水样加标回收率均值和RSD分别为73.1%～130%和1.4%～19%(n=6)。该方法适用于饮用水源水中挥发性有机物的监测分析。     

顶空固相微萃取-气质法测定水中嗅味物质

建立了一种测定水中土臭素、2-甲基异莰醇、吲哚和3-甲基吲哚的方法——顶空固相萃取(HS-SPME)和气相色谱/质谱(GC/MS)法,该方法可以检测到ng/L级的致嗅物质。详细研究了萃取纤维头的选择、萃取时间和温度、样品含盐量对HS-SPME的影响。在优化条件下,本法测定2-甲基异莰醇和土臭素的线性范围为5~200 ng/L,相关系数分别为0.999 7、0.999 8;测定吲哚和3-甲基吲哚的线性范围为200~5 000 ng/L,相关系数0.995;方法检出限分别为2.34、2.04、98.1、93.1 ng/L;低浓度下RSD20%,高浓度下RSD10%;水样加标回收率为89.7%~109.5%。以IBMP为内标物,将本法成功应用于饮用水源、饮用水、河涌水中土臭素、2-甲基异莰醇、吲哚和3-甲基吲哚的测定,结果令人满意。     

超高效液相色谱串联质谱测定中水中喹诺酮类抗生素

建立了检测中水中14种喹诺酮类抗生素残留的超高效液相色谱串联质谱(UPLCMS/MS)方法。水样通过HLB固相萃取小柱富集后,经C18色谱柱分离,运用乙腈-0.2%甲酸的10 mmol/L甲酸铵溶液进行梯度洗脱,质谱仪检测。采用电喷雾正模式电离(ESI+),多反应监测(MRM)模式进行检测,外标法定量。在1~100 ng/m L的线性范围内,各物质的线性关系良好,线性相关系数均≥0.991,方法的检出限为0.2~1.0 ng/L,定量限为0.5~2.0 ng/L,回收率稳定,RSD≤16%。该方法方便、准确,适用于中水中抗生素的痕量分析。     

气相色谱质谱法测定水中土臭素和二甲基异莰醇

建立了固相微萃取-气相色谱/质谱联用测定水中土臭素和二甲基异莰醇的方法。待测化合物二甲基异莰醇和土臭素的出峰时间分别是10.358和14.303min,内标物3-异丁基-2-甲氧基吡嗪(IBMP)的出峰时间为9.988min。曲线的线性相关系数均在0.995以上,二甲基异莰醇和土臭素的检出限分别为5.08和4.46 ng/L,相对标准偏差均小于5%,二甲基异崁醇的回收率在91.8%~109.0%,土臭素的回收率在91.1%~107.0%。     

超高效液相色谱/串联质谱法同时测定水中有机氯农药

应用固相萃取/超高效液相色谱/串联质谱法(UPLC-MS/MS)建立了水中18种有机氯农药(OCPs)的分析方法。通过对固相萃取柱、淋洗液、流动相等的优化,确定以Oasis HLB固相萃取柱、二氯甲烷-丙酮(8∶2,V/V)为淋洗液、甲醇-水(75∶25,V/V)为流动相做水样预处理。在最优条件下,目标物在水中回收率为79.0%~127.8%,相对标准偏差为6.8%~9.8%,线性范围均在1~2 000μg/L,线性相关系数(R~2)0.999。该方法具有检测限低、回收率高等优点,经实际样品测试,适用于水中18种OCPs残留的同时检测。     

固相萃取/高效液相色谱/串联质谱法同时测定水中雌激素

配合固相萃取预处理技术,采用HPLC-MS/MS内标分析方法检测了污水厂处理流程及其受纳水体污水水样中的雌激素雌酮(E1)、雌二醇(E2)、炔雌醇(EE2)和硫酸雌酮(E1-3-S)浓度,水样中四种目标物均有检出,受纳水体中E1-3-S的当量浓度分别占到E1当量浓度和计算总雌激素浓度的49.4%和19.1%(均折算为E2当量)。本检测方法色谱峰可有效分离,单个混合样的分析周期为12.0 min,线性范围分别为(0.5~100.1)、(0.4~98.8)、(0.1~99.4)和(0.2~100.0)ng/mL,方法检测限分别为0.5、0.4、0.1和0.2 ng/L,测定结果的精密度及加标回收率均良好。     

液液微萃取气相色谱测定水中邻苯二甲酸二(2-乙基己基)酯

以甲基叔丁基醚为萃取剂,采用液液微萃取和氢火焰离子化检测器气相色谱法,实现了对水中邻苯二甲酸二(2-乙基己基)酯的快速测定.该方法的检测下限可以达到1μg/L,当水中目标物的浓度为0.05～5 mg/L时,该方法的检测相对标准偏差(RSD)均小于5.1%,加标回收率为96%～116%.对于各种不同浓度的目标物,该方法均具有较好的测定精密度和准确度.对实际污水样的测定结果表明,该方法可用于水中邻苯二甲酸二(2-乙基己基)酯的快速定性定量分析.     

HS-SPME-GC/MS法测定地表水中典型嗅味物质

采用顶空固相微萃取-气/质(HS-SPME-GC/MS)联用的方法对地表水中常见嗅味物质(2-甲基异茨醇、β-环柠檬醛、土臭素、β-紫罗兰酮)进行分析测定。通过试验确定了HS-SPME的最佳萃取条件:萃取时间为30 min,萃取温度为55℃,NaCl的投加量为30%(m/V),搅拌强度为500 r/min,萃取纤维在GC上的解吸时间为3.0 min。在最佳条件下,4种物质在1～1 000 ng/L范围内呈良好的线性关系,r2为0.993 3～0.997 5,最低检出限为0.7～1.1 ng/L(S/N=3),相对标准偏差(n=6)为2.95%～7.9%,加标回收率为89.7%～103.2%。该方法可简单、快速地测定水中痕量嗅味物质。     

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%。     

催化剂对油脂与甘油酯交换反应的影响

合成两种碱性离子液体[Bmim]OH和[Bmim]Im,通过核磁对其进行结构表征,通过热重分析比较其热稳定性,并考察[Bmim]OH、[Bmim]Im和NaOH这3种催化剂对大豆油和甘油酯交换反应的影响。结果表明:[Bmim]Im的热稳定性远好于[Bmim]OH,而[Bmim]OH由于热稳定性较差,不能有效地催化酯交换反应;[Bmim]Im可发挥碱催化剂与相转移催化剂的双重作用,具有最高的催化活性,在反应温度为190℃、反应时间为3 h、催化剂用量为10%、醇油摩尔比为6∶1的条件下,甘油单酯的收率可达64.46%,明显高于相同条件下以NaOH为催化剂时的收率。     

Routine monitoring of antibiotics in water and wastewater with a radioimmunoassay technique

Antibiotics are one of a group of pharmaceutical compounds that have been found in lakes and streams throughout the world and the occurrence of these compounds in the environment has raised concerns regarding the toxicity to aquatic organisms and the emergence of strains of antibiotic-resistant bacteria. The objective of this study was to assess the use of a relatively simple coupled solid-phase extraction (SPE)/radioimmunoassay (RIA) method for screening and/or monitoring tetracycline (TC) and sulfonamide (SA) compounds in water. Cross-reactivity of TCs and SAs was used to determine the specificity of the assays. The results indicate that TC, oxytetracycline (OTC), chlortetracycline (CTC) of the investigated 5 TCs, and sulfamethazine (SMT), sulfamethoxazole (SMX), sulfadimethoxane (SDM) and sulfathiazole (STZ) of the investigated 6 SAs in water matrix cross-react to a similar degree within each family in RIA and SPE/RIA. Water samples were collected across a watershed in northern Colorado in addition to the influent and effluent of a wastewater treatment plant. SPE/RIA analysis of these samples was compared with SPE/liquid chromatography (LC)-mass spectrometry (MS) quantification of 5 TC and 6 SA compounds. Results of the study indicate that SPE/RIA can be an effective technique for monitoring antibiotic compounds in waters suspected to be contaminated with these compounds. The coupled method provides a sufficiently low detection limit (0.05 microg/L) to screen large sample sets at environmentally relevant concentrations. The method provides a semi-quantitative composite measurement of similar compounds in an antibiotic family without complex and expensive analytical equipment.     

Application of ultrasound-assisted emulsification-micro-extraction for the analysis of organochlorine pesticides in waters

Ultrasound-assisted emulsification-micro-extraction (USAEME) procedure was developed for the determination of different organochlorine pesticides (OCPs) in water samples by gas chromatography with μ-electron capture detection (GC-μECD). After the determination of the most suitable extraction solvent and its volume, parameters such as extraction time, centrifugation time and ionic strength of the sample were optimized by using a 2³ factorial experimental design. For 10 mL of water sample, the optimized USAEME procedure used 200 μL of chloroform as extraction solvent, 15 min of extraction without ionic strength adjustment at 25 °C and 5 min of centrifugation at 4000 rpm. Limits of detection ranged from 0.002 to 0.016 μg L⁻¹. Mean recoveries of OCPs from fortified water samples are over 96% for three different fortification levels between 0.5 and 5 μg L⁻¹ and relative standard deviations of the recoveries are below 9%. The developed procedure was successfully applied for real water samples (i.e., tap water, well water, surface (lake) water, domestic and industrial wastewater). Performance of the procedure was compared with those involving traditional liquid-liquid extraction and solid-phase extraction. The result demonstrates that the USAEME procedure is viable, rapid and easy to use for analysis of OCPs in water samples.     

A novel process utilizing subcritical water and nitrilotriacetic acid to extract hazardous elements from MSW incinerator fly ash

An effective process for hazardous element extraction from municipal solid waste incinerator fly ash was developed. The key trait of the process was to extract most of the hazardous elements out of the ash but leave Ca and Si inside the residue. In the extraction process, the ash was firstly pre-washed with water, then subjected to subcritical water (SC water) treatment and nitrilotriacetic acid (NTA) extraction. SEM images indicated that SC water is strong enough to destroy the ash particles, thus greatly improving hazardous elements extraction efficiency in the subsequent NTA extraction process. The extraction percentages for Cr, As, Se, Cd and Pb under SC water+NTA treatment were around 2-6 times higher than those treated by NTA at room conditions. The preferable SC treatment temperature was 573 K and the treatment time was 3 h. The optimum NTA concentration, vibration time and liquid/solid ratio were 0.8 M, 5 h and 10:1 (ml/g), respectively. Furthermore, it was found that introduction of a suitable amount of sulfuric acid into the extraction solution could extract more than 90% of most of the hazardous elements out of the ash.     

Countercurrent liquid/liquid extraction for analysis of organic water pollutants by GC/MS

A continuous countercurrent liquid/liquid extractor was developed to concentrate trace organic pollutants from large water samples. Non-volatile hydrophobic pollutants were extracted using methylene chloride in a pulsed column system (1 m × 15 mm ID). The procedure follows EPA method 625 to separate the water sample into basic/neutral and acidic compounds.Methylene chloride was chosen from a number of possible solvents (di-isopropylether, chloroform, hexane, ethyl acetate). Solvent efficiencies were studied using ultrapure water containing different model compounds (dimethylphtalate, anthracene, diphenylamine, atrazine, lindane, heptachlor, methyl parathion, 2-chlorophenol, 2,4-dichlorophenol, 2,4,6-trichlorophenol, 2-chloro,4-nitrophenol). Methylene chloride was found to be the most efficient extractant of both non-polar and polar chemicals. Recoveries ranged between 75% and 96% after one step batch liquid/liquid extraction, except for dimethylphtalate (38%).Pulsed column efficiency was evaluated for a 10 litre ultrapure water sample spiked with the same organic compounds as mentioned above (0.4–1.3 μg/l concentration range). The average recovery was found to be 86%. Continuous countercurrent extractor efficiency was comparable with that observed after a three step batch liquid/liquid extraction. Further, method sensitivity and sample representativity were both improved (concentration factor of 10,000 after 10 litre water extraction). The pulsed column, especially when coupled with GC/MS, can be used to identify trace organic pollutants at the ng/l level in natural waters.Countercurrent liquid/liquid extraction was applied to the analysis of natural surface waters from the Rhône River (France). Results are discussed with regard to EPA and EEC priority lists. Pollutants (such as organochlorine pesticides, triazines, monoaromatic and polyaromatic hydrocarbons, nitrophenols and chlorophenols) were identified by GC/MS at the ng/l level together with several natural organic compounds. Pulsed column extraction can thus be considered as an appropriate multiresidue method for monitoring pollution in natural water.     

Comparative study of pre-treatment procedures for H monitoring in water samples from environmental protection programs

The determination of tritium activity in water samples is included in most environmental protection programs, and the recommended procedure consists of sample distillation and further measurement by liquid scintillation. Distillation is a simple but time consuming pre-treatment, especially in routine analysis. Here we evaluate alternative pre-treatments for tritium activity determination, such as filtration or the use of multiple selective ion exchange columns. 52 samples from different water sources (rain, surface, underground, sea and drinking water) in Spanish environmental protection programs, together with an IAEA reference material were analyzed. Results show that both pre-treatments can be applied as a preliminary tool to discriminate between tritium active and non active waters in environmental monitoring programs. In addition, filtration and multiple selective ion exchange column pre-treatments can be used as alternative procedures for tritium activity determination in the routine analyses of water samples with known and reproducible chemical and isotopic composition. Both methods are less time consuming than distillation and, in the case of filtration, extremely cheap.For waters with complex matrices, especially sea water, distillation is the recommended procedure due to the interference from salts contained in the sample.     

离子传输型抗渗涂料对水泥基材料冻融自修复的影响

通过对水泥砂浆的基准样和离子传输型抗渗涂层试样冻融循环后,在不同养护时间和养护条件下抗渗性能和力学性能的测试,并利用SEM对试样微观结构的观察,研究了离子传输型抗渗涂料对水泥基材料冻融自修复作用的影响。结果表明:基准样在冻融循环后,通过养护能够实现一定程度的抗渗性能和力学性能的自修复,但是这种自修复的能力有限,而采用离子传输型抗渗涂料进行表面处理,可使水泥基材料具有很强的自修复能力,从而大大提高水泥基材料的抗渗性能和力学性能。SEM研究表明,离子传输型抗渗涂料主要是通过活性离子传输,在水泥基材料内部空隙和裂缝中反应生成大量针状结晶,堵塞内部孔隙,封闭毛细孔通道,从而提高水泥基材料的抗渗性能和力学性能。     

甲亚胺-H酸分光光度法测定岩盐中总硼

沸水溶解岩盐样品,过滤除去水不溶物,分取部分滤液在pH值5．2～5．6乙酸铵缓冲液中,硼可与甲亚胺-H酸生成可溶性的棕黄色络合物,吸光度与硼的浓度成正比。其标准回收率为94．9％～102．4％,相对标准偏差为0．79％～1．26％（RSD,N=5）。建立的分析方法准确度、灵敏度、精密度高,方法简便、快速,适用于各类岩盐中总硼含量的分析研究。     

Cloud point extraction for speciation of chromium in water samples by electrothermal atomic absorption spectrometry

A new method based on the cloud point extraction (CPE) separation and electrothermal atomic absorption spectrometry (ETAAS) detection was proposed for the determination of chromium species. When the system temperature is higher than the cloud point extraction temperature (CPT) of selected surfactant p-octyl polyethyleneglycolphenyether (Triton X-100), the complex of Cr(VI) with dibromophenylfluorone (Br-PF) could enter surfactant-rich phase, whereas the Cr(III) remained in aqueous phase. Thus, an in situ separation of Cr(VI) and Cr(III) could be realized. Cr(VI) in surfactant-rich phase was analyzed by ETAAS and Cr(III) was calculated by subtracting of Cr(VI) from the total chromium which was directly determined by ETAAS. The main factors affecting the cloud point extraction, such as pH, concentration of Br-PF and Triton X-100, equilibration temperature and time, were investigated systematically. Under the optimized conditions, the quantitation limit for Cr(VI) as low as 0.01 microg/L was obtained by preconcentrating a 10 mL sample solution, and the relative standard deviation (n=6, c=2.0 microg/L) was 2.6%. The proposed method was applied to the speciation of chromium in different water samples and the recoveries in the range of 98.9-105.3% were obtained by spiking the real samples. In order to verify the accuracy of the method, a certified reference water sample was analyzed and the results obtained were in good agreement with the certified values.     

Determination of caffeine as a tracer of sewage effluent in natural waters by on-line solid-phase extraction and liquid chromatography with diode-array detection

A new liquid chromatographic (LC) method with automated on-line solid phase extraction was developed to determine caffeine at sub-microgram per litre concentrations in waters. The filtered sample was pre-concentrated in a pre-column, which was backwashed with acidic water at pH of 2.70. The concentrated caffeine was separated using a C18 column with a gradient of water-acetonitrile and detected by diode array detection (DAD) at 210 nm. Four different pre-columns: C18, PRP-1, PLRP-s and Env were evaluated for the on-line solid phase extraction of caffeine. The PLRP-s pre-column allowed the enrichment of up to 100 mL of environmental water sample with highest recovery. The procedure was validated by recovery experiments in water spiked at 0.5 1.0 and 4.0 microg/L. Average recoveries were between 92.1 +/- 5.2% and 97.8 +/- 2.6%. Detection limits as low as 0.1 microg/L from 50 ml of sample were achieved. The proposed method has the advantages of higher reliability and sensitivity, simpler sample preparation and shorter analysis time in comparison with off-line solid-phase extraction. The utility of the method was demonstrated at two field sites: Bolivar and Halls Head (Australia). At Bolivar, the treatment process included 6-week lagoon storage which is believed to have attenuated caffeine, and thus limited its use as an environmental tracer of reclaimed water. At the Halls Head site, where the storage period is shorter, caffeine was detected in both the treated sewage effluent and in groundwater near ponds where the reclaimed water is at similar concentrations. These results suggest that the environmental conditions under which caffeine is conservative require better definition.     

Ionic liquids for extraction of metals and metal containing compounds from communal and industrial waste water

In a fundamental study the potential of ionic liquids based on quaternary ammonium- and phosphonium cations and thiol-, thioether-, hydroxyl-, carboxylate- and thiocyanate-functionalized anions has been assessed for future application in advanced sewage treatment. The elimination of the metal(oid)s Ag, As, Cd, Cr, Cu, Hg, Ni, Pb, Pt, Sn, Zn and the cancerostatic platinum compounds cisplatin and carboplatin was screened using a liquid phase micro-extraction set-up. The analytical tool-set consisted of ICP-SFMS and LC-ICP-MS for quantification of metal(oid)s and cancerostatic platinum compounds, respectively. The purity of the ILs was assessed for the investigated metal(oid)s on the base of present EU environmental quality standards and was found to be sufficient for the intended use. In model solutions at environmental relevant concentrations extraction efficiencies ≥95% could be obtained for Ag, Cu, Hg and Pt with both phosphonium- and ammonium-based ILs bearing sulphur functionality in the form of thiosalicylate and 2-(methylthiobenzoate) anions, as well as with tricaprylmethylammonium thiocyanate within an extraction time of 120 min. All other metals were extracted to a lower extent (7-79%). In the case of cancerostatic platinum compounds a phosphonium-based IL bearing thiosalicylate functionality showed high extraction efficiency for monoaquacisplatin.For the first time, liquid phase micro extraction with ionic liquids was applied to industrial and communal waste water samples. The concentration of all investigated metal(oid)s could be significantly reduced. The degree of elimination varied with the initial concentration of metals, pH and the amount of suspended particulate matter.