排序方式: 共有45条查询结果,搜索用时 15 毫秒
21.
Study on biotinylation strategies for competitive immunoassay of estradiol (E2) was carried out. Two types of competitive enzyme immunoassay (EIA) with Biotin-Avidin amplification system were established and optimized.The E2-Biotin conjugate was used as a tracer in one assay, and biotinylated antibody was used as a tracer in the other. In both of EIAs, horseradish peroxidase-labelled Avidin (Avidin-HRP) was used with a spectrometric determination of enzyme activity. The precision, sensitivity and specificity were measured and compared. The results showed that although both were satisfactory in specificity, the EIA with hapten-Biotin showed to be superior to the EIA with biotinylated antibody in sensitivity and precision. The limit of detection of serum E2 was 8 and 50 pg/mL with E2-Biotin and biotinylated antibody as tracer, respectively. 相似文献
22.
Shimon Farber Bernard S. Green Abraham J. Domb 《Journal of polymer science. Part A, Polymer chemistry》2009,47(20):5534-5542
An efficient novel method for the synthesis of a covalent molecularly imprinted polymer (MIP) highly specific to β‐estradiol have been developed. MIP prepared by both covalent and non covalent techniques, demonstrated high selectivity toward β‐estradiol. MIPs were synthesized by radical polymerization of 17‐β‐estradiol 4‐vinyl‐benzene carboxyl or sulfonyl esters used as covalent functional monomers, methacrylic acid as noncovalent functional monomer, ethylene glycol dimethacrylate as crosslinking agent, and acetonitrile as swelling and porogenic component. Almost 35% (w/w) of 17‐β‐estradiol was successfully removed from the polymer network by basic hydrolysis. The binding ability of MIP was 10.73 μg/mg MIP following removal of 17‐β‐estradiol in the 2 mg/mL β‐estradiol solution. Selective rebinding of β‐estradiol toward MIP was tested in the presence of competitive binders including estrone, 19‐nortestosterone, epiandrosterone, and cholesterol. Estrone having closest similar chemical structure to β‐estradiol exhibited only 0.6 μg/mg MIP competitive binding, being exposed to equivalent concentrations. Moreover, other competitive steroids demonstrated negligible affinity toward MIP indicating high selectivity of novel MIP system toward β‐estradiol. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5534–5542, 2009 相似文献
23.
《Analytical letters》2012,45(17):2758-2773
Abstract A new immunoassay method using surface plasmon resonance (SPR) coupled with online, in-tube, solid-phase microextraction (SPME) was developed and applied to detect estradiol in human serum and seawater using an indirect inhibitive immunoassay format. The binding of antibody was inhibited by estradiol in a dose-dependent manner, and the calibration curve was generated by linear fit over the range of 0.3125–20.0 ng/ml, with a correlation coefficient of R2 = 0.99996. The detection limit (S/N = 3) was 0.17 ng/ml. This study demonstrates, for the first time, the feasibility of in-tube SPME-SPR to determine estradiol in human serum and seawater. 相似文献
24.
25.
Pekka Keski‐Rahkonen Kaisa Huhtinen Reena Desai D. Tim Harwood David J. Handelsman Matti Poutanen Seppo Auriola 《Journal of mass spectrometry : JMS》2013,48(9):1050-1058
Accurate measurement of estradiol (E2) is important in clinical diagnostics and research. High sensitivity methods are critical for specimens with E2 concentrations at low picomolar levels, such as serum of men, postmenopausal women and children. Achieving the required assay performance with LC–MS is challenging due to the non‐polar structure and low proton affinity of E2. Previous studies suggest that ionization has a major role for the performance of E2 measurement, but comparisons of different ionization techniques for the analysis of clinical samples are not available. In this study, female serum and endometrium tissue samples were used to compare electrospray ionization (ESI), atmospheric pressure chemical ionization (APCI) and atmospheric pressure photoionization (APPI) in both polarities. APPI was found to have the most potential for E2 analysis, with a quantification limit of 1 fmol on‐column. APCI and ESI could be employed in negative polarity, although being slightly less sensitive than APPI. In the presence of biological background, ESI was found to be highly susceptible to ion suppression, while APCI and APPI were largely unaffected by the sample matrix. Irrespective of the ionization technique, background interferences were observed when using the multiple reaction monitoring transitions commonly employed for E2 (m/z 271 > 159; m/z 255 > 145). These unidentified interferences were most severe in serum samples, varied in intensity between ionization techniques and required efficient chromatographic separation in order to achieve specificity for E2. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
26.
Ultra‐performance liquid chromatography–tandem mass spectrometry assay for determination of plasma nomegestrol acetate and estradiol in healthy postmenopausal women 下载免费PDF全文
《Biomedical chromatography : BMC》2018,32(2)
A highly sensitive and selective ultra‐performance liquid chromatography–tandem mass spectrometry method is described for the simultaneous determination of nomegestrol acetate (NOMAC), a highly selective progestogen, and estradiol (E2), a natural estrogen in human plasma. NOMAC was obtained from plasma by solid‐phase extraction, while E2 was first separated by liquid–liquid extraction with methyl tert‐butyl ether followed by derivatization with dansyl chloride. Deuterated internal standards, NOMAC‐d5 and E2‐d4 were used for better control of extraction conditions and ionization efficiency. The assay recovery of the analytes was within 90–99%. The analytes were separated on UPLC BEH C18 (50 × 2.1 mm, 1.7 μm) column using a mobile phase comprising of acetonitrile and 3.0 mm ammonium trifluoroacetate in water (80:20, v/v) with a resolution factor (Rs) of 3.21. The calibration curves were linear from 0.01 to 10.0 ng/mL for NOMAC and from 1.00 to 1000 pg/mL for E2, respectively. The intra‐ and inter‐batch precision was ≤5.8% and the accuracy of quality control samples ranged from 96.7 to 103.4% for both analytes. The practical applicability of the method is demonstrated by analyzing samples from 18 healthy postmenopausal women after oral administration of 2.5 mg nomegestrol acetate and 1.5 mg estradiol film‐coated tablets under fasting. 相似文献
27.
Dandan Chen Xiuhua Wei 《International journal of environmental analytical chemistry》2016,96(14):1389-1401
In this work, a piezoelectric immunosensor is developed for the detection of estradiol (E2). The gold-coated chip of quartz crystal microbalance was modified by a 3-mercaptopropionic acid self-assembly monolayer, activated by carbodiimide/n-hydroxylsuccinimide, and then to immobilise the E2 antibody via the interaction with their amine groups. The resonance frequency change resulted by the binding of E2 on immobilised antibody differs from that of a blank (ΔF), was correlated to the antigen concentration. The construction of the sensing interface was confirmed by electrochemical impedance spectroscopy. Both round-off or dynamic modes were explored as analytical detection strategy in this work. Using round-off mode, the output ΔF responds to the concentration of E2 with a detection limit of 0.04 μg mL?1 and a linear range from 0.1 to 10 μg mL?1. Meanwhile, using a dynamic mode, the presence of E2 induced in a real-time sensing output along with the incubation of antigen. The slope of sensing output is in linear relation with the concentration of E2 with a detection limit of 0.06 μg mL?1. Thus, a faster immunesensing technique is established for rapid analysis requiring only several seconds other than the round-off mode which needs a complete incubation period for at least 60 min. This finding will greatly promote the applicability of immunosensor for rapid, real-time or in-site assays. 相似文献
28.
《Journal of separation science》2017,40(12):2620-2628
In this work, a fast and effective dispersive liquid–liquid microextraction was developed for the isolation and preconcentration of free 17 β‐estradiol, the main human estrogen, from real human urine samples. To optimize the extraction technique, few important parameters such as type and volume of extraction and dispersive solvents, centrifugation conditions, effect of salt addition, and extraction time were studied. Optimal conditions were obtained when injecting 600 μL mixture of tetrachloromethane as extraction solvent and ethanol as dispersive solvent (1:5, v/v) into 2 mL of urine containing 8% NaCl and following centrifugation at 10 000 rpm, thus reaching enrichment factor 28 and extraction recovery 98% for estradiol. Procedure was evaluated by means of high‐performance liquid chromatography with UV detection (λ = 280 nm) using a C‐18 column and methanol/water (60:40, v/v) as the mobile phase. The method was linear within the concentration range 1.0–250.0 mg/L (r = 0.9997) and provided a limit of detection of 0.25 mg/L. The proposed method was applied to the determination of free estradiol in real human pregnancy urine. 相似文献
29.
30.