A simple and selective high‐performance liquid chromatography method coupled with fluorescence detection was developed for the simultaneous measurement of trace levels of four estrogens (estrone, estradiol, estriol and 17α‐ethynyl estradiol) in environmental matrices. For feces samples, solid–liquid extraction was applied with a 1:1 v/v mixture of acetonitrile and ethyl acetate as the extraction solvent. For liquid samples (e.g., leachate and groundwater), hydrophobic/lipophilic balanced automated solid‐phase extraction disks were selected due to their high recoveries compared to conventional C18 disks. Chromatographic separations were performed on a reversed‐phase C18 column gradient‐eluted with a 45:55 v/v mixture of acetonitrile and water. The detection limits were down to 1.1 × 10?2 (estrone), 4.11 × 10?4 (estradiol), 5.2 × 10?3 (estriol) and 7.18 × 10?3 μg/L (17α‐ethynyl estradiol) at excitation/emission wavelengths of 288/310 nm, with recoveries in the range of 96.9 ± 3.2–105.4 ± 3.2% (n = 3). The method was successfully applied to determine estrogens in feces and water samples collected at livestock farms and a major river in Northeast China. We observed relatively high abundance and widespread distribution of all four estrogens in our sample collections, implying the urgency for a comprehensive and intricate investigation of estrogenic fate and contamination in our researched area. 相似文献
The effect of intermolecular hydrogen bonding on the photophysical properties of N‐methyl‐1,8‐naphthalimide ( 2 ) has been investigated by time‐dependent density functional theory (TD‐DFT) method. The UV and IR spectra of 2 monomer and its hydrogen‐bonded complexes formed with 2,2,2‐trifluoroethanol (TFE) 2 +TFE and 2 +2TFE have been calculated, which confirm the presence of intermolecular hydrogen bonding interactions between the carbonyl groups of the aromatic imide and the hydroxyl group of the polyfluorinated alcohol. The absorption and fluorescence intensities going from 2 monomer via hydrogen‐bonded complex 2 +TFE to 2 +2TFE were found to be gradually enhanced with the wavelength gradually red‐shifted. The enhancements of the fluorescence intensities from 2 monomer to hydrogen‐bonded complexes 2 +TFE and 2 +2TFE were attributed to the decrease of the intersystem crossing (ISC) efficiency from the first excited singlet state S11(ππ*) to the second excited triplet state T23(nπ*), whose energy was increased relative to its ground state due to the intermolecular hydrogen bonding interactions. 相似文献
Abstract Separation of monoglucuronides of estrone, estradiol, estriol and 16-epiestriol by high-performance liquid chromatography on a reversed-phase column has been carried out. The effects of pH and salt concentration of a mobile phase on the k' value were investigated with a TSK GEL LS-410 ODS-SIL column. Isomeric monoglucuronides of estriol and 16-epiestriol were distinctly separated on this column when 0.7% disodium hydrogen phosphate (pH 3.0)/tetrahydrofuran was used as a mobile phase. 相似文献
Abstract A sensitive solid‐phase extraction‐enzyme‐linked immunosorbent assay (SPE‐ELISA) method was developed to analyze the estrone in environmental water. A new SPE sorbent of the multiwall carbon nanotube was tested and proved to have similar adsorbability for estrone comparing to the commercial C18 SPE. A specific polyclonal antibody for estrone (A‐E1) and a broad‐spectrum antibody for estrone, estradiol and estriol (A‐E2) were produced. For A‐E1, the limit detection of estrone was 0.04 µg/l and for A‐E2 were 0.07, 0.04 and 0.2 µg/l of estrone, estradiol and estriol, respectively. Different river water samples were analyzed by ELISA and HPLC method. 相似文献
An isocratic reversed phase high performance liquid chromatography procedure utilizing ultraviolet and fluorescence detectors linked in series is described for the analysis of cortisone (E), cortisol (F), corticosterone (B), 11-deoxycortisol (S), 11-deoxycorticosterone (DOC), androstenedione (A), testosterone (T), 17-hydroxyprogesterone (17-OHP), progesterone (P), estriol, estradiol, estrone, prednisone acetate and dexamethasone acetate in serum. Serum specimens were extracted with ethyl ether. The optimized mobile phase was methanol + tetrahydrofuran + water (26:18:56, v/v/v). A Shim-pack ODS column was used. The recoveries were 80 to 103%. Intra- and inter-day coefficient of variance were less than 8%. The detection limit is 0.5 pmol per injection volume for estriol, estradiol, E, F and B; 1 pmol for S, A, DOC and estrone; 2 pmol for T and 17-OHP; and 4 pmol for P. Serum from normal subjects and patients with congenital adrenal hyperplasia due to 21- or 17-hydroxylase deficiency were measured, as well as samples of maternal and umbilical cord serum. 相似文献
Abstract We report a sensitive high performance liquid chromatography (HPLC) method for determination of free and conjugated estrogens (estrone, estradiol and estriol) by a fluorescent pre-labeling regent, 2-(4-carboxyphenyl)-5,6-dimethylbenzimidazole, with modification of previous work. The modified method was also tried, in preliminary work, for diagnosis of the in-vitro fertilization embryo transfer (IVF-ET) process. The reagent volumes were changed to one-tenth, derivatization conditions were changed to mild conditions at 40 C, and a solid-phase extraction process by SEP-PAK could be omitted after restudy of reaction conditions. As a result analysis time could be shorted within 40 min. The proposed HPLC method was applied to monitoring of free and conjugated estrogens in the patients who attend in-vitro fertilization embryo transfer (IVF-ET). The subsequent increase of free and conjugated estrone, estradiol and estriol was observed with the progress of follicle growth following ovulation stage in the IVF-ET process. We tried to plot estrogens for assist of clinical diagnosis of IVF-ET. The free estrone: 200-600 pg/ml, estradiol: 200-600 pg/ml and estriol: 100-300 pg/ml, conjugate estrone: 1000-5000 pg/ml, estradiol: 3000-8000 pg/ml and estriol: 2000-7000 pg/ml) in the patients without hormone disease were observed before human chorionic gonadotropin stimulation (hCG) on IVF-ET process. It was expected that free estrogen values, especially E1 and E3 could be use as validation products for diagnosis of hormone disease in IVF-ET process. 相似文献
It is shown that intramolecular hydrogen bonding between the and the ortho carbonyl on the side chain of N'formylkynurenine and some parent compounds plays an important role on their spectroscopic properties. The fluorescence emissionλmax is shifted by about 4000 cm?1 in going from polar to non-polar solvents. This abnormally red-shifted fluorescence is attributed to an excited state proton transfer from the formamido to the ortho carbonyl of the side chain. 相似文献
In this paper, we report the preparation and red-light-emitting behavior of benzothiadiazole–tris(alkyloxy)phenylethene dyes. In solution, we observed an efficient red light emission with high fluorescence quantum yields (up to 0.78). With increase in solvent polarity, the emission bands shifted to longer wavelengths accompanied by a large Stokes shift of up to 152 nm. A moderate fluorescence quantum yield of 0.52 could be achieved even in the polar solvent dimethylformamide. Red light emission with good fluorescence quantum yields (up to 0.50) was also observed in the bulk solid, liquid, and film state. 相似文献
The development of a simple and sensitive analytical approach that combines multiple monolithic fiber solid‐phase microextraction with liquid desorption followed by high‐performance liquid chromatography with diode array detection is proposed for the determination of trace levels of seven steroid sex hormones (estriol, 17β‐estradiol, testosterone, ethinylestradiol, estrone, progesterone and mestranol) in water and urine matrices. To extract the target analytes effectively, multiple monolithic fiber solid‐phase microextraction based on a polymeric ionic liquid was used to concentrate hormones. Several key extraction parameters including desorption solvent, extraction and desorption time, pH value and ionic strength in sample matrix were investigated in detail. Under the optimal experimental conditions, the limits of detection were found to be in the range of 0.027–0.12 μg/L. The linear range was 0.10–200 μg/L for 17β‐estradiol, 0.25–200 μg/L estriol, ethinylestradiol and estrone, and 0.50–200 μg/L for the other hormones. Satisfactory linearities were achieved for analytes with the correlation coefficients above 0.99. Acceptable method reproducibility was achieved by evaluating the repeatability and intermediate precision with relative standard deviations of both less than 8%. The enrichment factors ranged from 54‐ to 74‐fold. Finally, the proposed method was successfully applied to the analysis of steroid sex hormones in environmental water samples and human urines with spiking recoveries ranged from 75.6 to 116%. 相似文献
The fluorescence lifetimes of the estrogens, estrone, 17β‐estradiol and 17α‐ethinylestradiol, were studied in various solvents. The fluorescence lifetimes of 17β‐estradiol and 17α‐ethinylestradiol decreased from 4.7 to 0.9 ns as the solvent hydrogen bond accepting ability increased, in good agreement with other phenolic molecules. Estrone's two fluorescence bands had distinct lifetimes, with the 304 nm band having a lifetime shorter than 200 ps, reflecting efficient energy transfer to the carbonyl group, which had lifetimes ranging from 4.4 to 4.9 ns depending on the solvent. Solvent effects on the 1ππ*, 1πσ* and 1nπ* states that are relevant to estrogen photophysics can adequately explain these trends. The solvent dependence on the excited states of these potent endocrine disruptors has significant implications for their photochemistry. 相似文献
This paper presents the development and comparison of procedures for the qualitative and quantitative determination of five estrogenic compounds (17-α-ethynylestradiol, estrone, estradiol, estriol, and progesterone) in drinking water and wastewater samples. Five extraction columns and two disks were tested for their efficiency. The C18 columns were superior on the basis of cost for solid phase extraction of drinking water or sewage. However, the best recoveries were achieved using extraction disks. High-performance liquid chromatography with diode array, fluorescence, and tandem mass spectrometry detectors were compared for selectivity, repeatability, and linearity of response. Solid phase extraction with high-performance liquid chromatography and tandem mass spectrometry was the most sensitive, efficient, and precise for the determination of hormones in drinking water and wastewater. This method satisfied analytical validation criteria and was characterized by a low limit of detection at the pg-ng/L level. The study also considered challenges that emerged for steroidal hormone determination in aqueous samples. 相似文献
This paper investigates how solution conditions, especially solvent polarity and hydrogen bonding, affect the fluorescence of ellipticine, a natural plant alkaloid with anticancer activity. A total of 16 solvents that cover a wide range of polarities were tested. The ultraviolet (UV) absorption and fluorescence emission of ellipticine were found to be solvent dependent. The absorption and emission maximum shifted to higher wavelengths (red shift) with increased solvent polarity. The difference in absorption and emission maximum (Stokes' shift) was large, approximately 10,000-11,000 cm-1, in polar solvents (with orientation polarizability Deltaf>0.2) but unusually small, approximately 8900 cm-1, in nonpolar solvents (hexane and cyclohexane). Large Stokes' shifts were due to an intramolecular charge transfer (ICT), which was enabled by large solvent polarity and hydrogen bonding of ellipticine with the solvents. Two transitions were found in the Lippert-Mataga plot between (1) nonpolar and semipolar solvents and between (2) semipolar and polar solvents. The first transition reflected the formation of hydrogen bonds between ellipticine and the solvents whereas the second transition indicated that ellipticine underwent an ICT. In addition, the larger extinction coefficients and the longer lifetime of ellipticine obtained in protic solvents were attributed to the formation of stronger hydrogen bonds. The photophysical response of ellipticine to changes in solvent polarity and hydrogen bond formation could be used to infer the location of ellipticine in a heterogeneous medium, namely liposomes in aqueous solution. A relatively large red shift of emission in liposomes indicated that ellipticine may be in a more polar environment with respect to the lipid bilayer, possibly close to the hydrophilic interface. 相似文献
Although there are existing methods for determining estrogen in human bodily fluids including blood plasma and serum, very little information is available regarding estrogen levels in human cerebrospinal fluid (CSF), which is critical to assess in studies of neuroprotective functions and diffusion of neuroprotective estrogens across the blood–brain barrier. To address this problem, a liquid chromatography with tandem mass spectrometry method for the simultaneous quantification of four endogenous estrogens (estrone, 17α‐estradiol, 17β‐estradiol, and estriol) in human CSF was developed. An aliquot (300 μL) of human CSF was bulk derivatized using dansyl chloride in the sample and 10 μL was directly injected onto a restricted‐access media trap column for protein removal. No off‐line sample extraction or cleanup was needed. The limits of detection of estrone, 17α‐estradiol, 17β‐estradiol, and estriol were 17, 28, 13, and 30 pg/mL, respectively, which is in the parts‐per‐trillion regime. The method was then applied to human CSF collected from ischemic trauma patients. Endogenous estrogens were detected and quantified, demonstrating the effectiveness of this method. 相似文献
In this study we present a pressurized liquid extraction/liquid chromatography-tandem mass spectrometry (PLE/LC-MS-MS) method to determine a group of estrogens and conjugated estrogens in sewage sludge. Parameters that affect the extraction step such as extraction solvent, temperature, pressure, static extraction time, number of cycles, purge time and flush volume have been optimized. In the LC-MS-MS system, electrospray ionization and a triple quadrupole analyzer have been used, and the multiple reaction monitoring mode has enabled low levels of target analytes to be detected. All recoveries were higher than 81% except for estrone 3-glucoronide and estradiol 17-glucoronide which were not extracted and consequently, they were not considered in the present study. The repeatability and reproducibility between days expressed as %RSD (n=3), were lower than 6% and 9%, respectively. The method developed allowed the target analytes to be quantified at low levels of microg/kg. The limits of detection were lower than 26 microg/kg of dry weight (d.w.) of sewage sludge, except for 17 alpha-estradiol, 17beta-estradiol, 17 alpha-ethinylestradiol and estradiol 17-acetate whose values were between 150 and 175 microg/kg (d.w.). The method was applied to determine these compounds in sewage sludge from two domestic sewage treatment plants. Estrone 3-sulfate, estradiol 3-sulfate, diethylstilbestrol, estrone and estriol were determined in some samples and estriol showed the highest value (406 microg/kg d.w.). 相似文献
It has been found that gold nanoparticles (nano-Au) enhance the chemiluminescence (CL) of the luminol–hydrogen peroxide system
and that estrogens inhibit these CL signals in alkaline solution. CL spectra, UV–visible spectra, X-ray photoelectron spectra
(XPS), and transmission electron microscopy (TEM) were used to investigate the mechanism of the CL enhancement. On the basis
of the inhibition, a flow-injection CL method has been established for determination of three natural estrogens. Under the
optimized conditions, the linear range for determination of the estrogens was 0.07 to 7.0 μmol L−1 for estrone, 0.04 to 10 μmol L−1 for estradiol, and 0.1 to 10 μmol L−1 for estriol. The detection limits were 3.2 nmol L−1 for estrone, 7.7 nmol L−1 for estradiol, and 49 nmol L−1 for estriol, with RSD of 2.9, 2.6, and 1.8%, respectively. This method has been used for analysis of estrogens in commercial
tablets and in urine samples from pregnant women. 相似文献
We demonstrate here that supramolecular interactions enhance the sensitivity towards detection of electron‐deficient nitro‐aromatic compounds (NACs) over discrete analogues. NACs are the most commonly used explosive ingredients and are common constituents of many unexploded landmines used during World War II. In this study, we have synthesised a series of pyrene‐based polycarboxylic acids along with their corresponding discrete esters. Due to the electron richness and the fluorescent behaviour of the pyrene moiety, all the compounds act as sensors for electron‐deficient NACs through a fluorescence quenching mechanism. A Stern–Volmer quenching constant determination revealed that the carboxylic acids are more sensitive than the corresponding esters towards NACs in solution. The high sensitivity of the acids was attributed to supramolecular polymer formation through hydrogen bonding in the case of the acids, and the enhancement mechanism is based on an exciton energy migration upon excitation along the hydrogen‐bond backbone. The presence of intermolecular hydrogen bonding in the acids in solution was established by solvent‐dependent fluorescence studies and dynamic light scattering (DLS) experiments. In addition, the importance of intermolecular hydrogen bonds in solid‐state sensing was further explored by scanning tunnelling microscopy (STM) experiments at the liquid–solid interface, in which structures of self‐assembled monolayer of the acids and the corresponding esters were compared. The sensitivity tests revealed that these supramolecular sensors can even detect picric acid and trinitrotoluene in solution at levels as low as parts per trillion (ppt), which is much below the recommended permissible level of these constituents in drinking water. 相似文献
Solvatochromic and prototropic behaviour of 4-aminodiphenylamine (4ADA) and 4,4'-diaminodiphenylamine (DADA) have been investigated in the solvents of different polarity and at various acid-base concentrations in the ground and excited states using absorption and fluorescence spectra. Solvatochromic shifts have been analysed and observed shifts are explained by the hydrogen bonding interactions. The prototropic study reveals that (i) absorption maximum of monocation of DADA is red shifted to its neutral form, and (ii) the fluorescence of 4ADA is red shifted on protonation. The abnormal fluorescence of 4ADA+ is found to be due to large solvent relaxation in polar medium. 相似文献