首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 62 毫秒
1.
We investigated contamination by endocrine-disrupting chemicals in drinking water from 35 major Italian cities and five popular Italian brands of bottled mineral water. The quality of Italian drinking water was assessed by combing chemical analysis with bioassay to quantify specific estrogenic contaminants and to characterize the actual biological effect of the mixture of chemicals present in drinking water including the contribution of not targeted compounds. The selected contaminants were natural and synthetic steroid estrogens, alkylphenols and bisphenol A, linuron, triazine herbicides, and their metabolites. A specific analytical method was developed based on solid phase extraction of 1 L of water and concentration to 100 μL for quantification by electrospray ionization liquid chromatography tandem mass spectrometry, achieving quantification limits of 0.05–0.36 ng/L for herbicides and 0.64–7.70 ng/L for steroids and phenols. No steroid estrogens were detected in any of the samples, while bisphenol A and nonylphenols were detected in the ranges of 0.82–102.00 and 10.30–84.00 ng/L respectively. Herbicides and their degradation products, when present, were found from slightly above the quantification limits up to 49.91 ng/L, mainly from cities in northern Italy. Chemical analyses were complemented by the performance of a bioassay for the determination of the estrogenic activity in the extracts based on the transactivation of estrogen receptor α-transfected reporter HeLa-ERE-Luciferase-Neomycin cell line. Activity was generally low with maximum estrogenicity of 13.6 pg/L estradiol equivalents.  相似文献   

2.
Trichlorophenols such as 2,4,5-trichlorophenol (2,4,5-TCP) and 2,4,6-trichlorophenol (2,4,6-TCP) are organochlorine compounds to which the general public can be exposed via contaminated food, water, and air. This study assessed exposure to 2,4,5-TCP and 2,4,6-TCP in Koreans age 18–69 years based on the Korean National Human Biomonitoring Survey conducted in 2009. Using data from 1,865 representative Koreans, we found that the geometric mean urinary concentrations of 2,4,5-TCP and 2,4,6-TCP were 83.4 pg/mL [95 % confidence interval (CI)?=?78.6–88.6] and 0.39 ng/mL (95 % CI?=?0.35–0.42), respectively. The creatinine-adjusted geometric mean 2,4,5-TCP and 2,4,6-TCP levels were 78.8 ng/g creatinine (95 % CI?=?73.8–84.1) and 0.36 μg/g creatinine (95 % CI?=?0.33–0.40), respectively. Of the Korean adult population, about 67.5 and 87.5 % had respective urine 2,4,5-TCP and 2,4,6-TCP concentrations >0.05 ng/mL (the limit of detection, LOD). Urine 2,4,5-TCP concentrations were significantly associated with age and place of residence, whereas urine 2,4,6-TCP concentrations were higher in rural residents. These findings suggest that most Koreans had detectable levels of 2,4,5-TCP and 2,4,6-TCP in their urine and that the body burden of 2,4,5-TCP and 2,4,6-TCP varied according to demographic and geographic factors.  相似文献   

3.
Livestock operations are associated with emissions of odor, gases, and particulate matter. The majority of previous livestock odor studies focused on swine operations whereas relatively few relate to dairy cattle. Identifying the compounds responsible for the primary odor impact is a demanding analytical challenge because many critical odor components are frequently present at very low concentrations within a complex matrix of numerous insignificant volatiles. The objective of this study was to describe a chemical-sensory profile of dairy manure odor using headspace solid-phase microextraction (HS-SPME) and multidimensional gas chromatography-mass spectrometry-olfactometry (MDGC-MS-O). Two analytical approaches were used: (1) HS-SPME time-series extractions (from seconds up to 20 hr) followed by gas chromatography-mass spectrometry-olfactometry (GC-MS-O) analyses, and (2) relatively short HS-SPME extractions (30 min) followed by MDGC-MS-O analyses on selected chromatogram heart-cuts. Dairy manure was collected at research dairy farms in the United States and Israel. Volatile organic compounds (VOCs) resolved from multiple analyses included sulfur-containing compounds, volatile fatty acids, ketones, esters, and phenol/indole derivatives. A total of 86 potential odorants were identified. Of them, 17 compounds were detected by the human nose only. A greater number of VOCs and odorous compounds were detected, as well as higher mass loading, on solid-phase microextraction (SPME) fibers observed for longer extractions with SPME. However, besides sulfur-containing compounds, other selected compounds showed no apparent competition and displacement on the SPME fiber. The use of MDGC-MS-O increased chromatographic resolution even at relatively short extractions and revealed 22 additional odorants in one of the regions of the chromatogram. The two analytical approaches were found to be parallel to some extent whereas MDGC-MS-O can also be considered as a complementary approach by resolving more detailed chemical-sensory odor profiles.  相似文献   

4.
A pan-European monitoring campaign of the wastewater treatment plant (WWTP) effluents was conducted to obtain a concise picture on a broad range of pollutants including estrogenic compounds. Snapshot samples from 75 WWTP effluents were collected and analysed for concentrations of 150 polar organic and 20 inorganic compounds as well as estrogenicity using the MVLN reporter gene assay. The effect-based assessment determined estrogenicity in 27 of 75 samples tested with the concentrations ranging from 0.53 to 17.9 ng/L of 17-beta-estradiol equivalents (EEQ). Approximately one third of municipal WWTP effluents contained EEQ greater than 0.5 ng/L EEQ, which confirmed the importance of cities as the major contamination source. Beside municipal WWTPs, some treated industrial wastewaters also exhibited detectable EEQ, indicating the importance to investigate phytoestrogens released from plant processing factories. No steroid estrogens were detected in any of the samples by instrumental methods above their limits of quantification of 10 ng/L, and none of the other analysed classes of chemicals showed correlation with detected EEQs. The study demonstrates the need of effect-based monitoring to assess certain classes of contaminants such as estrogens, which are known to occur at low concentrations being of serious toxicological concern for aquatic biota.  相似文献   

5.
Parabens have been widely used as antimicrobial agents, mainly in food products, pharmaceuticals, and cosmetics. Although they are known as safe preservatives, they also cause some harm to human health, which has been discussed lately. Therefore, the aim of this study was to evaluate the occurrence of nine parabens (including isomers) in mineral and drinking waters, besides in drinking water treatment sludge (DWTS) samples with determination by liquid chromatography tandem mass spectrometry (LC-MS/MS). Both methods solid phase extraction (SPE) and QuEChERS were validated. Calibration curves showed a correlation coefficient of 0.99 for all compounds. LOQ values ranged from 0.04 to 4 μg L?1 in aqueous matrices and from 5 to 500 ng g?1 in DWTS. Recoveries between 70 and 115% were reached with RSD below 20% for all compounds in SPE whereas recoveries between 62 and 119% were found with RSD below 20% for almost all compounds in QuEChERS. Matrix effect had low values (<?20%); it was only above 20% for methylparaben in the SPE and for pentylparaben in the QuEChERS. Using a quick and simple extraction procedures with SPE, QuEChERS, and LC-MS/MS analyses, these methods proved to be selective and sensitive. They were successfully applied to real samples (treated water, mineral water, and sludge), and methylparaben was detected at concentration levels below 0.242 μg L?1 in mineral and treated water samples and 10 ng g?1 in DWTS samples.  相似文献   

6.
This study was aimed to determine the presence of 69 organic contaminants in 77 representative bottled waters collected from 27 countries all over the world. All water samples were contained in polyethylene terephthalate bottles. Target compounds were (1) environmental contaminants (including 13 polycyclic aromatic hydrocarbons (PAHs), 31 pesticides including organochlorine (OCPs), organophosphorus, and pyrethroids; 7 polychlorinated biphenyls (PCBs); and 7 triazines) and (2) plasticizers (including 6 phthalates and 5 other compounds). Samples were analyzed by stir bar sorptive extraction followed by gas chromatography-tandem mass spectrometry. PAHs, OCPs, PCBs, and triazines, which are indicators of groundwater pollution, were not detected in most of the samples, except for naphthalene (0.005–0.202 μg/L, n?=?16). On the other hand, plastic components were detected in 77 % of the samples. Most frequently detected compounds were dimethyl phthalate and benzophenone at concentrations of 0.005–0.125 (n?=?41) and 0.014–0.921 (n?=?32), respectively. Levels detected are discussed in terms of contamination origin and geographical distribution. Target compounds were detected at low concentrations. Results obtained showed the high quality of bottled water in the different countries around the world.  相似文献   

7.
Simple and effective extraction methods based on matrix solid-phase dispersion (MSPD), dispersive liquid–liquid microextraction (DLLME), and solid-phase extraction (SPE) coupled with high-performance liquid chromatography with diode array detector (HPLC-DAD) were developed to determine triketone herbicides—sulcotrione (SUL), mesotrione (MES), tembotrione (TEMB), and their degradation products—in plant tissues and water samples. The extraction procedures were employed to enable quantification of the accumulation of selected triketone herbicides and their degradation products in a model aquatic plant, Egeria densa. To obtain comprehensive information about the triketones' influence on an aquatic plant, changes in chlorophyll concentration in plants exposed to these triketones were monitored. The average recovery ranged from 58 to 115 % (coefficients of variation 7–12 %) for plant tissues and from 52 to 96 % (coefficients of variation 8–20 %) for water samples. The limit of detection (LOD) for the MSPD–HPLC-DAD procedure was in the range of 0.06–0.23 μg/g, whereas for DLLME–HPLC-DAD and SPE–HPLC-DAD, LOD was in the range of 0.06–0.26 μg/mL. Symptoms of the phytotoxicity of sulcotrione, mesotrione, tembotrione, and their degradation products (decrease of chlorophyll concentration in plant sprouts) were observed for E. densa cultivated in water with herbicide concentrations of 100 μg/L. Moreover, the tembotrione degradation product exhibited a high level of accumulation and low metabolism in plant tissues in comparison to the other triketones and their degradation products.  相似文献   

8.
Organochlorine pesticides were determined in water and sediment samples collected from the littoral zone of Lake Prespa, as well as from its three main tributaries (the rivers Golema, Brajcinska and Kranska), during the period 2004 to 2006. In addition, muscle tissue samples of barbus fish (Barbus prespensis Karaman, 1928) collected from the littoral zone of Lake Prespa were also analysed. The obtained results give an overview of the contamination levels of these problematic compounds at their potential sources in the river mouths, in the potentially affected, species-rich littoral section of the lake and in the muscle tissue of one selected fish species, collected near the rivers’ deltas. Special attention was paid to the presence of some DDT metabolites (1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (p,p′–DDE); (1,1-dichloro-2,2-bis(p-chlorophenyl)ethane (p,p′–DDD) and 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (p,p′–DDT). The extraction of pesticides from water samples was done by liquid-liquid partition in dichloromethane. For the sediment and fish tissue we used solid-liquid extraction. The extracted residues were analyzed on a gas chromatograph equipped with an electron capture detector (GC-ECD). The results of the respective studies indicated the presence of DDT metabolic forms in the samples of the three analysed matrixes. The highest levels of presence for these pollutants were found in the muscle tissue of the fish samples. The total DDTs content in the analysed muscle tissue samples range from 11.67 to 13.58 μg kg?1of fresh tissue. The average total DDTs content for the sediment samples were within the range of 2.32 to 4.17 μg kg?1 of dry sediment. Higher DDT metabolites content were found in the sediments collected from the rivers than in the samples from the littoral zone. The lowest average total concentrations of DDTs, on the other hand, were recorded in the water samples and ranged between 0.036 and 0.057 μg L?1. The obtained results indicated that the dominant metabolic form in the samples of the three investigated matrixes (water, sediment and fish tissue) from Lake Prespa was p,p′-DDE. There was a very good linear correlation in this study between the content of DDT's (total DDT metabolites) detected and the percentage of total organic material in the sediment. The detected concentrations are clearly below the toxicity thresholds; consequently, severe effects on the endemic species of Lake Prespa are not very likely.  相似文献   

9.
Group-selective magnetic molecularly imprinted polymers (MMIPs) that can extract four widely used sulfonamide antibiotics and their acetylated metabolites from environmental water were synthesized in this study. The MMIPs with saturation magnetization value of 16.7 emu g-1 could be separated from the environmental water samples easily by the application of an adscititious magnetic field, reducing the time consumption of pretreatment. The extraction conditions were evaluated, and optimal extraction conditions were as follows: extraction time, 25 min; amount of polymers, 90 mg; washing solvent, 30 % methanol aqueous solution; and elution solvent, methanol–acetic acid (95:5, v/v). The target analytes were detected by liquid chromatography–tandem mass spectrometry, and the detection limits of the method are in the range of 0.38–1.32 ng L-1. The relative standard deviations of intra- and inter-day are in the range of 1.3–6.8 % and 1.7–9.1 %, respectively. The proposed method is suitable for the analysis of environmental water samples.  相似文献   

10.
An efficient pretreatment and analytical method was developed to investigate the occurrence and fate of four free estrogens (estrone (E1), 17β-estradiol (17β-E2), estriol (E3), and 17α-ethinylestradiol (EE2)), four conjugated estrogens (estrone-3-sulfate sodium salt (E1-3S), 17β-estradiol-3-sulfate sodium salt (E2-3S), estrone-3-glucuronide sodium salt (E1-3G), and 17β-estradiol-3-glucuronide sodium salt (E2-3G)), and bisphenol A (BPA) in three livestock farms raising beef cattle, cows, sheep, swine, and chickens in Qi County, which is located in North China. The results demonstrated that one cow and one beef cattle excreted 956.25–1,270.41 and 244.38–319.99 μg/day of total (free and conjugated) estrogen, respectively, primarily through feces (greater than 91 %), while swine excreted 260.09–289.99 μg/day of estrogens, primarily through urine (98–99 %). The total estrogen excreted in sheep and broiler chicken feces was calculated to be 21.64–28.67 and 4.62–5.40 μg/day, respectively. It was determined that conjugated estrogens contributed to 21.1–21.9 % of the total estrogen excreted in cow feces and more than 98 % of the total estrogen excreted in swine urine. After composting, the concentration of total estrogen decreased by 18.7–59.6 %; however, increased levels of BPA were measured. In treated compost samples, estrogens were detected at concentrations up to 74.0 ng/g, which indicates a potential risk of estrogens entering the surrounding environment.  相似文献   

11.
The presence of residual organochlorine and organophosphorus pesticides was evaluated at different periods of sugarcane cultivation in agricultural soil and water samples from the town of Tlaltizapan, which is located in the state of Morelos in Mexico, to determine the presence and persistence of these compounds and their possible effects on the region. The compounds p,p′-DDE, p,p′-DDD (metabolites of p,p′-DDT), γ-HCH and heptachlor were found in more of 95% of the sampling zones in the three monitoring periods performed along 2 years. The highest concentration detected (129.6 μg/kg dry soil) was for α-HCH, but its frequency of detection was ~5%. The low detection frequency of α-HCH and the high concentration values of γ-HCH indicate the repeated use of technical-grade HCH and Lindane (γ-HCH) in the region. Among the organophosphorus pesticides, ethyl parathion was the compound with the highest soil concentration, at ~2000 μg/kgdry soil, during the initial monitoring. However, this compound was detected in the second monitoring with a concentration of ~4 μg/kgdry soil, but it was not detected in the third, indicating that is was not accumulated in the environment. The heptachlor was the compound most commonly found in all water samples, within a range of 0.45–1.25 ng/L. The presence of this organochlorine compound in the water samples indicated a possible migration from the soil to water bodies due to soil erosion. The presence of organophosphorus compounds was not detected in the water samples, which could be attributed to the moderate persistence of these compounds and their consequent degradation before arriving at the water bodies.  相似文献   

12.
Lee MR  Chang CM  Dou J 《Chemosphere》2007,69(9):1381-1387
A trace analytical method of benzene, toluene, ethylbenzene and xylenes (BTEX) in water has been developed by using headspace solid-phase microextraction (HS-SPME) coupled to cryo-trap gas chromatography-mass spectrometry (GC-MS). The chromatographic peak shape for BTEX was improved by using cryo-trap equipment. The HS-SPME experimental procedures to extract BTEX from water were optimized with a 75 microm carboxen/polydimethylsiloxane (CAR/PDMS)-coated fiber at a sodium chloride concentration of 267 g l(-1), extraction for 15 min at 25 degrees C and desorption at 290 degrees C for 2 min. Good linearity was verified in a range of 0.0001-50 microg l(-1) for each analyte (r(2)=0.996-0.999). The limits of detection (LODs) of BTEX in water reached at sub-ng l(-1) levels. LODs of benzene, toluene, ethylbenzene, m/p-xylene and o-xylene were 0.04, 0.02, 0.05, 0.01 and 0.02 ng l(-1), respectively. The proposed analytical method was successfully used for the quantification of trace BTEX in ground water. The results indicate that HS-SPME coupled to cryo-trap GC-MS is an effective tool for analysis of BTEX in water samples at the sub-ng l(-1) level.  相似文献   

13.
Assessment of levels of polybrominated diphenyl ethers (PBDEs) from the sediment of Asunle stream, an adjourning stream of the Obafemi Awolowo University dumpsite, has been carried out. Sediment samples were collected from the stream at six locations for a period of 8 months, composed of 4 months each of wet (May–Aug) and dry (Nov–Feb) seasons. Soxhlet extraction was employed for the isolation of all the target compounds from the sediment samples. Extracts were further subjected to multi-layer column chromatography employing different forms of silica gel. The prepared samples were analyzed using GC-MS. The overall mean concentrations of the total PBDEs ranged from 1.80 to 9.46 ng/g. The results showed that the concentrations of the PBDEs were slightly higher during the wet season than those during the dry season. In all the studied locations, BDE28, BDE47, BDE99, BDE100, BDE153, and BDE154 were detected in all the sediment samples at concentrations that ranged from 0.73 to 10.43 ng/g. Results of this study indicated that BDE153 was the major pollutant of the Asunle stream sediments.  相似文献   

14.
This work describes the analysis of 15 pharmaceutical compounds, belonging to different therapeutic classes (anti-inflammatory/analgesics, lipid regulators, antiepileptics, β-blockers and antidepressants) and with diverse physical–chemical properties, in Spanish soils with different farmland uses. The studied compounds were extracted from soil by ultrasound-assisted extraction (UAE) and determined, after derivatization, by gas chromatography with mass spectrometric detection (GC–MS). The limits of detection (LODs) ranged from 0.14 ng g?1 (naproxen) to 0.65 ng g?1 (amitriptyline). At least two compounds where detected in all samples, being ibuprofen, salicylic acid, and paracetamol, the most frequently detected compounds. The highest levels found in soil were 47 ng g?1 for allopurinol and 37 ng g?1 for salicylic acid. The influence of the type of crop and the sampling area on the levels of pharmaceuticals in soil, as well as their relationship with soil physical–chemical properties, was studied. The frequent and widespread detection of some of these compounds in agricultural soils show a diffuse contamination, although the low levels found do not pose a risk to the environment or the human health.  相似文献   

15.
Abstract

A simple, very efficient method is presented for routine analysis of herbicide Krovar I? (active components bromacil and diuron) in water and soil samples. Water samples were extracted by liquid–liquid extraction with dichloromethane (DCM) as extraction solvent. For soil samples two different extraction techniques were compared: microwave-assisted solvent extraction and a shaking technique using a platform shaker. Extracts were analyzed by high performance liquid chromatography using a water:methanol gradient. Liquid chromatography was coupled with atmospheric pressure chemical ionization mass spectrometry (LC-APCI-MS) for quantification of bromacil and diuron. Optimization of the APCI-MS was done by using standards in the flow injection analysis mode (FIA). Method detection limit for liquid samples for bromacil is 0.04 µg L?1 and for diuron 0.03 µg L?1. Method detection limit for soil samples is 0.01 µg g?1 dry weight for both compounds. Results of analysis of field samples of water and soil are also presented.  相似文献   

16.
A novel analytical-scale concept to improve reliability of detection and analysis of natural and processed wastewater samples from a purification plant was developed. A sequential sample clean-up system of polymer-based octadecyl and silane-based quaternary amine sorbents were used for concentrating human based steroid hormones and their metabolites and detecting them by UV absorption with capillary electrophoresis (CE). The water samples were collected from influent and effluent processes of the water purification plant in Helsinki, Finland.The CE methods were partial-filling micellar electrokinetic chromatography and capillary zone electrophoresis. The analysis times and method concentration levels were optimized with eight steroids at the range of 0.5–10 mg/L. Since in CE the detectable quantities were higher than the existing amounts in the process waters, the real samples needed matrix removal combined with steroid enrichment. After 20,000-fold concentration testosterone-glucoside, androstenedione, progesterone, and estradiol-glucoside could be determined in the process water samples. The amounts of individual steroids in influent and effluent waters were 0–429 and 0–207 ng/L, respectively. Correspondently, their total amounts were 735 and 212 ng/L with excellent in day and inter-day repeatability. The RSD values were less than 1, 9.7, and 19% in repeated analyses, calculated from 60 analyses during 24 h, and from 130 analyses during 15 months, respectively. The steroid removal in purification process was 65% on average. The solid particles separated in three steps during the water clean-up concept contained 9.8–45 ng/g steroids in combined dry precipitates.  相似文献   

17.
The aim of this work was to develop a simple and fast analytical method for the determination of a wide range of organic compounds (volatile and semivolatile compounds) in municipal wastewater. The headspace-solid-phase microextraction (HS-SPME) and gas chromatography (with mass spectroscopy) was used for determination of the organic compounds. In this study, 39 organic compounds were determined, including 3 sulfur compounds, 28 substituted benzenes, and 8 substituted phenols. The extraction parameters, such as types of SPME fiber, extraction temperature, extraction time, desorption time, salt effect, and magnetic stirring, were investigated. The method had very good repeatability, because the relative standard deviations ranged from 0.5 to 12%. The detection limit of each compound was at or below the microgram-per-liter level. This method was applied for determination of the organic compounds in raw wastewater, primary effluent, secondary effluent, and chlorinated secondary effluent samples from the Chania Municipal Wastewater Treatment Plant (Crete, Greece).  相似文献   

18.
The pollution levels of typical semivolatile organic compounds (SVOCs) consisting of 15 polycyclic aromatic hydrocarbons (PAHs), 20 organic chlorinated pesticides (OCPs), and 15 phthalate esters (PAEs) were investigated in small rivers running through the flourishing cities in Pearl River Delta region, China. The concentrations of ∑15PAHs were 2.0–48 ng/L and 29–1.2?×?103 ng/g in the water and sediment samples, respectively. The ∑20OCPs were 6.6–57 ng/L and 9.3–6.0?×?102 ng/g in the water and sediment samples, respectively. The concentrations of ∑15PAEs were much higher both in the water and sediments. The partition process of the detected SVOCs between the water and sediment did not reach the equilibrium state at most of the sites when sampling. The combustion of petroleum products and coal was the major source of the detected PAHs. The OCPs were mainly historical residue, whereas the new inputs of dichlorodiphenyltrichloroethane (DDT), chlordane, and endosulfan were possible at several sites. The industrial and domestic sewage were the major source for the PAEs; storm water runoff accelerated the input of PAEs. No chronic risk of the SVOCs was identified by a health risk assessment through daily water consumption, except for the ∑20OCPs that might cause cancer at several sites. Nevertheless, the integrated health risk of the SVOCs should not be neglected and need intensive investigations.  相似文献   

19.
The effect of elapsed time between spraying and first leaching event on the leaching behavior of five herbicides (terbuthylazine, S-metolachlor, mesotrione, flufenacet, and isoxaflutole) and two metabolites (desethyl-terbuthylazine and diketonitrile) was evaluated in a 2011–2012 study in northwest Italy. A battery of 12 lysimeters (8.4 m2 long with a depth of 1.8 m) were used in the study, each filled with silty-loam soil and treated during pre-emergence with the selected herbicides by applying a mixture of commercial products Lumax (4 L ha?1) and Merlin Gold (1 L ha?1). During treatment periods, no gravity water was present in lysimeters. Irrigation events capable of producing leaching (40 mm) were conducted on independent groups of three lysimeters on 1 day after treatment (1 DAT), 7 DAT, 14 DAT, and 28 DAT. The series was then repeated 14 days later. Leachate samples were collected a few days after irrigation; compounds were extracted by solid phase extraction and analyzed by high-performance liquid chromatography and gas chromatography–mass spectrometry. Under study conditions, terbuthylazine and S-metolachlor showed the highest leaching potentials. Specifically, S-metolachlor concentrations were always found above 0.25 µg L?1. Desethyl-terbuthylazine was often detected in leached waters, in most cases at concentrations above 0.1 µg L?1. Flufenacet leached only when irrigation occurred close to the time of herbicide spraying. Isoxaflutole and mesotrione were not measured (<0.1 µg L?1), while diketonitrile was detected in concentrations above 0.1 µg L?1 on 1 DAT in 2011 only.  相似文献   

20.
A novel pipette-tip extractor of a graphene/poly (vinyl alcohol) cryogel (graphene/PVA) composite sorbent was prepared to preconcentrate carbamate pesticides in environmental water samples before analysis with a gas chromatograph-flame ionization detector (GC-FID). This novel pipette-tip extractor with the graphene/PVA sorbent exhibited a high porosity when observed through a scanning electron micrograph (SEM). Under optimal conditions, using only 1.0 mL of sample and 0.75 mL of eluting solvent, the developed method provided a wide linear range of 10–700 ng mL?1 and 10–500 ng mL?1 with limit of detection (LOD) of 6.40 ± 0.18 and 9.17 ± 0.34 ng mL?1 for carbofuran (2,3-dihydro-2,2-dimethylbenzofuran-7-yl methylcarbamate) and carbaryl (1-naphthyl methylcarbamate), respectively. The pipette-tip extractor provided high extraction efficiency with high accuracy indicated, by good recoveries in the range of 74.5 ± 4.8% to 119.7 ± 1.6% and 76 ± 15% to 114 ± 19% for carbofuran and carbaryl, respectively. In addition, the fabrication procedure showed a good pipette-tip extractor-to-pipette-tip extractor reproducibility with a relative standard deviation of 1.3–9.8% (n = 5). When the developed pipette-tip extractor was applied for the extraction of carbofuran and carbaryl in surface water samples near vegetable plantation areas, 25.9 ± 8.2 ng mL?1 of carbofuran was found, and carbaryl was also detected in concentrations that ranged from 45.0 ± 4.0 to 191 ± 13 ng mL?1.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号