固相萃取-超高压液相色谱-串联质谱法测定海水中16种磺胺类抗生素残留

利用固相萃取前处理方法,净化和富集海水中的16种磺胺类抗生素,采用超高压液相色谱-串联质谱法进行定性和定量检测,建立了完整的海水中磺胺类抗生素的检测方法,并对质谱条件、液相条件和固相萃取条件进行了优化。实验结果表明,16种磺胺类抗生素在0.1～100μg/L质量浓度范围内线性良好,相关系数均可以达到0.996以上,方法检出限为0.3~1.1 ng/L。对水样进行高、中、低3个质量浓度的加标回收实验,回收率分别为82.3%~125.7%,73.3%~125.1%和75.2%~119.2%,相对标准偏差为2.4%~12.0%。该方法具有操作简便、重现性好、灵敏度高的优点,可用于海水中磺胺类抗生素的监测分析。     

海水石油类分析的影响因素

石油类是衡量海水水质的重要指标,海洋石油的首要污染源是原油泄漏,因此海水石油类的具体成分与原油成分基本一致,主要为弱极性的烷烃、环烷烃和芳香烃。在3种国标分析方法中,紫外分光光度法的应用最为广泛。采用该法分析时,建议统一选择HJ油标准作为标准溶液,透光率90%的正己烷作为萃取剂,标准曲线斜率在斜率控制图内的上下辅助限之内;萃取过程中调节水样p H值2,人工萃取时间120 s,萃取后不能立即分析时,在5℃冰箱内保存不超过2周。     

海水中半挥发性有机化合物的萃取/GC-MS/SIM定量分析方法研究

采用萃取/GC-MS/SIM法对海水中250种半挥发性目标化合物同时进行定量分析,方法的最低检出限范围在0.004μg/L～0.060μg/L之间,绝大多数化合物的回收率在60%～150%之问.     

紫外光度法测定海水石油类质控指标研究

采取问卷调查的形式对76家"近海网"成员单位海水石油类测定情况进行调查,根据调查问卷获得的数据信息,结合实验室数据,采用控制图法确定了紫外光度法测定海水石油类质控指标限值,包括萃取剂透光率、检出限、校准曲线斜率、平行样偏差等。     

硅胶分离-气相色谱法测定海水样品中的有机氯农药及多氯联苯

建立了硅胶净化-具电子捕获检测器气相色谱(GC-ECD)测定海水样品中有机氯农药(OCPs)、多氯联苯(PCBs)的方法。海水样品经正己烷萃取,浓缩萃取液后过硅胶层析柱,通过梯度淋洗进行样品的净化和分离,采用GC-ECD进行分析测试。OCPs回收率达70.7%~109.2%,PCBs回收率达92.6%~119.2%。采用GC-MS进行辅助确证,结果表明,方法可行。     

固相微萃取分析条件的优化

主要介绍了固相微萃取作为一种样品前处理技术，如何对影响其分配系数的各因素，如：萃取头的选择、萃取方式、萃取温度等进行优化选择，从而提高方法灵敏度及回收率。     

固相微萃取-毛细管气相色谱法快速同步分析水中硝基苯类及氯苯类化合物

固相微萃取是一种快速、简便、集萃取浓缩进样于一体的样品前处理技术,具有分析时间短、灵敏度高、无需有机溶剂的优点。文章用固相微萃取富集水中9种硝基苯类及5种氯苯类化合物,毛细管气相色谱ECD检测器分离分析,整个分析过程只需25min,检出限可达0.0002~0.02μg/L,已用于地表水、海水与工厂废水中硝基苯类及氯苯类化合物含量的测定。     

液液萃取-气相色谱-质谱法同时测定饮用水中的酞酸酯、百菌清和联苯胺

建立了液液萃取-气相色谱-质谱（LLE -GC/MS）同时测定饮用水中的6种酞酸酯类化合物、百菌清和联苯胺的方法。选用3种有机溶剂进行萃取，筛选出回收率高、操作简单的前处理方法，萃取后经气相色谱-质谱分析。方法表明：8种物质线性良好，相关系数为0．9978～0．9995，用二氯甲烷萃取回收率最佳，回收率在90．1％～118％之间，相对标准偏差在0．24％～7．21％之间。     

有机萃取-火焰原子吸收法测定海水中总铁

目前,国家水质分析规范中测定水中铁的方法很多,但对海水中铁的测定方法却很少,通过不断试验得出,在pH 3.5～3.7介质中,铁和二乙氨基二硫代甲酸钠(DDTC)形成螯合物,以有机试剂四氯化碳萃取,再以HNO3-H2O2溶液反萃取,可用火焰原子吸收分光光度法测定海水中总铁.……     

填充吸附微萃取-高效液相色谱法检测水中3种肼类

建立了基于填充吸附微萃取-液相色谱法检测水中肼、甲肼和偏二甲肼的方法。对影响方法效果的重要参数（如填充吸附微萃取的萃取材料、萃取循环次数和萃取速度、洗脱溶剂和洗脱体积、样品pH等）均进行了测试和优化。明确最优条件为先将样品pH调节为3.5，用HLB作为萃取材料，以15 μL/s的速度进行15次重复萃取，用100 μL含0.2%乙酸的乙腈进行洗脱。3种目标物在3 min内分离良好，并在10~500 μg/L范围内线性良好，相关系数范围为0.997 8~0.999 1，检出限范围为2.0~5.0 μg/L。在10、50、100 μg/L 3个浓度水平加标实验中，3种肼类的平均回收率为76.7%~96.5%，日内相对标准偏差为5.6%~9.1%，日间相对标准偏差为8.5%~16.7%。该方法能够满足水体中3种肼类物质的快速测定要求。     

洹河水中痕量有机污染物的研究

采用固相萃取技术 ,对洹河水中痕量有机物进行富集 ,大量的地表水被 C1 8键合相萃取后 ,洗脱液经干燥浓缩用于 GC和 GC/MS分析 ,鉴定出 64种有机物 ,并对苯系物、杂环类等 2 7种主要污染物作了定量测定 ,得出有机物的沿途变化规律。     

GC-MS分析碱法草浆造纸废水中的有机污染物组成

碱法草浆造纸废水在酸性条件下经乙醚萃取--K-D浓缩器浓缩,采用气相色谱-质谱(GC-MS)联用仪对其有机污染物进行了分析研究.结果表明,该废水中共含有29种有机物,其中主要为有机酸类,占有机物总量的50.84%.其次为难降解的呋喃类和毒性较大的苯环类有机物,它们分别占有机物总量的25.12%和13.53%.     

Using a Composite Membrane for Enhanced Sensitivity and Faster Response in On-line Membrane Extraction Microtrap Gas Chromatography

On-line membrane extraction microtrap (OLMEM) gas chromatography was used for continuous monitoring of volatile organic compounds (VOCs) in water. The aqueous sample flowed through tubular membrane and the VOCs selectively permeated through it. The permeated VOCs were stripped by a carrier gas and transported to a microtrap. The microtrap retained and concentrated the analytes before injecting into a GC. In this study, the performance of a composite membrane was compared with that of a conventional silicone membrane. The advantages of using the composite membrane were higher extraction efficiency and shorter response time. Extraction efficiencies as high as 95% were obtained for compounds such as toluene and trichloroethane.     

Penetration of polar brominated DBPs through the activated carbon columns during total organic bromine analysis

Total organic bromine (TOBr) is a collective parameter representing all the brominated organic disinfection byproducts (DBPs) in water samples. TOBr can be measured using the adsorption-pyrolysis method according to Standard Method 5320B. This method involves that brominated organic DBPs are separated from inorganic halides and concentrated from aqueous solution by adsorption onto the activated carbon (AC). Previous studies have reported that some commonly known brominated DBPs can partially penetrate through the AC during this adsorption step. In this work, the penetration of polar brominated DBPs through AC and ozone-modified AC was explored with two simulated drinking water samples and one chlorinated wastewater effluent sample. Polar brominated DBPs were selectively detected with a novel precursor ion scan method using electrospray ionization-triple quadrupole mass spectrometry. The results show that 3.4% and 10.4% of polar brominated DBPs (in terms of total ion intensity) in the chlorinated Suwannee River fulvic acid and humic acid samples, respectively, penetrated through the AC, and 19.6% of polar brominated DBPs in the chlorinated secondary wastewater effluent sample penetrated through the AC. The ozone-modification of AC minimized the penetration of polar brominated DBPs during the TOBr analysis.     

气相色谱-质谱法测定大气中98种挥发性有机物

通过色谱-质谱联用法(简称GC-MS),利用低温冷阱技术对大气中的VOCs进行浓缩富集,然后经过加热解吸分别至毛细管色谱柱和FID检测器及MS检测器,对大气中98种挥发性有机化合物(VOCs)进行分离、定性、定量测定。方法检出限为0.008×10-9~0.100×10-9(V/V);线性相关系数的平方值为0.992 7~1,相对标准偏差为4.0%~20.2%,总体标准偏差为0.154 2~0.952 1。     

超高效液相色谱-串联质谱法测定水中拟除虫菊酯和有机磷农药残留

采用直接进样法和萃取浓缩法2种前处理方式,通过超高效液相色谱-串联质谱法对水中20种拟除虫菊酯类和有机磷类农药进行了测定,并对仪器条件的选择和前处理条件的优化进行了探讨。结果表明,20种农药的线性关系良好,相关系数均>0.999,直接进样法检出限为0.21~2.47μg/L,回收率为81.0%~119%,相对标准偏差<10%。萃取浓缩法检出限为0.0022~0.0043μg/L,回收率为71.5%~115%,相对标准偏差<15%。该方法简便、快捷,精密度和准确度较高,可满足水中拟除虫菊酯类和有机磷类农药的检测要求。     

Aquatic humus from an unpolluted Brazilian dark-brown stream: general characterization and size fractionation of bound heavy metals

The main pool of dissolved organic carbon in tropical aquatic environments, notably in dark-coloured streams, is concentrated in humic substances (HS). Aquatic HS are large organic molecules formed by micro-biotic degradation of biopolymers and polymerization of smaller organic molecules. From an environmental point of view, the study of metal humic interactions is often aimed at predicting the effect of aquatic HS on the bioavailability of heavy metal ions in the environment. In the present work the aquatic humic substances (HS) isolated from a dark-brown stream (located in an environmental protection area near Cubat?o city in S?o Paulo-State, Brazil) by means of the collector XAD-8 were investigated. FTIR studies showed that the carboxylic carbons are probably the most important binding sites for Hg(II) ions within humic molecules. 13C-NMR and 1H-NMR studies of aquatic HS showed the presence of constituents with a high degree of aromaticity (40% of carbons) and small substitution. A special five-stage tangential-flow ultrafiltration device (UF) was used for size fractionation of the aquatic HS under study and for their metal species in the molecular size range 1-100 kDa (six fractions). The fractionation patterns showed that metal traces remaining in aquatic HS after their XAD-8 isolation have different distributions. Generally, the major percentage of traces of Mn, Cd and Ni (determined by ICP-AES) was preferably complexed by molecules with relatively high molecular size. Cu was bound by fractions with low molecular size and Co showed no preferential binding site in the various humic fractions. Moreover, the species formed between aquatic HS and Hg(II), prepared by spiking (determined by CVAAS), appeared to be concentrated in the relatively high molecular size fraction F1 (> 100 kDa).     

Screening and quantification of emerging contaminants in Periyar River,Kerala (India) by using high-resolution mass spectrometry (LC-Q-ToF-MS)

The presence of emerging contaminants (ECs) in different aquatic systems may contribute to hazardous effects on aquatic organisms and subsequently on human health. In the present work, liquid chromatography coupled to a quadrupole time of flight mass spectrometer (LC-Q-ToF-MS) was used to identify and quantify a series of ECs in Periyar River in Aluva region, Kerala, India. The water samples were pre concentrated using solid-phase extraction (SPE) prior to analysis. The compounds were probed in both positive and negative ionization mode using electro spray ionization (ESI). Method validations were performed for linearity, limit of detection (LOD), limit of quantification (LOQ), accuracy, and precision (intraday and inter day). The ECs were quantified using standard calibration curve. The identified nine ECs include pharmaceuticals, personal care products, steroids, surfactants, and phthalate. A relatively high concentration was observed in the case of 2-dodecyl benzene sulfonic acid (1012 ng/l) and low concentration was observed for lignocaine (4.3 ng/l; since this is below LOQ, the value is only approximate). In addition, we have identified another 28 organic compounds using the technique of non-target analysis out of which seven compounds fall in the category of surfactants. Being the first report on ECs in Periyar River, the data is very important as this river is one of the biggest and important rivers of Kerala having several purification units for drinking water in the province.     

Heavy metals in soils near the nickel smelter: chemistry,spatial variation,and impacts on plant diversity

Air pollution induced changes were observed both in plant communities and in soil chemistry in forest ecosystems near the nickel-copper smelter in the Kola Peninsula, Russia. All measured forest plant community parameters describing their floristic composition and structure were affected by pollution. Heavy metals were significantly concentrated in organic horizons of forest soils. The concentrations of ammonium acetate-extractable nickel and copper in organic horizons near the smelter were approximately two orders of magnitude higher than the background levels in the region. Based on pH values, air pollution has not resulted in a detectable topsoil acidification near the smelter. However, concentrations of extractable magnesium, potassium and nitrogen in organic horizons tended to be lower towards the smelter. The spatial variability of data obtained results in necessity of the two complementary, macroscopic and microscopic, approaches to ecosystem investigation. The macroscopic approach better revealed the influence of pollution. The ordination of the major species diversity indexes was highly related to soil properties, suggesting that the content of heavy metals and nutrients is the best soil related predictor of species diversity in polluted areas. Besides direct input of pollutants from the atmosphere, soil contamination and nutritional disturbance contribute significantly to the observed vegetation damage in subarctic forest ecosystems.     

Assessment and monitoring of nutrient loading in the sediments of tidal creeks receiving shrimp farm effluent in Quang Ninh, Vietnam

Coastal shrimp farming may lead to the contamination of sediments of surrounding estuarine and marine ecosystems as shrimp farm effluent often contains high levels of pollutants including a range of organic compounds (from uneaten feed, shrimp feces, and living and dead organisms) which can accumulate in the sediments of receiving waterways. The assessment and monitoring of sediment quality in tidal creeks receiving shrimp farm effluent can support environmental protection and decision making for sustainable development in coastal areas since sediment quality often shows essential information on long-term aquatic ecosystem health. Within this context, this paper investigates nutrient loadings in the sediments of tidal creeks receiving shrimp farm effluent in Quang Ninh, Vietnam, which now have a high concentration of intensive and semi-intensive shrimp farms. Sediment samples taken from inside creek sections directly receiving effluent from concentrated shrimp farms (IEC), from main creeks adjacent to points of effluent discharge outside concentrated shrimp farms (OEC), and few kilometers away from shrimp farms (ASF) as reference sites were collected and analyzed before and after shrimp crops to investigate spatial and temporal variation. The results showed that there were statistically significant differences in the concentrations of total nitrogen, total phosphorus, and total organic carbon among IEC, OEC, and ASF sites while the seasonal variation being limited over study times. A sediment nutrient index (SNI) computed from coefficient scores of the factor analysis efficiently summarizes sediment nutrient loads, which are high, albeit quite variable, in canals directly receiving effluents from farms but then decline sharply with distance from shrimp farms. The visualization and monitoring of sediment quality data including SNI on maps can strongly support managers to manage eutrophication at concentrated shrimp farming areas, contributing to sustainable development and management at coastal zones.