共查询到20条相似文献,搜索用时 31 毫秒
1.
A simple reversed-phase liquid chromatographic method with ultraviolet detector (378 nm) for the determination of nitrovin in feeds was improved and validated. The mobile phase was a mixture of acetonitrile and 0.1% formic acid solution (v/v) in the ratio of 50:50 (v/v), and the flow rate was set at 1.2 mL min?1. The extraction solution was a mixture of dimethyl formamide, acetonitrile and methanol (50:25:25, v/v), the sample was cleaned-up with reversed-phase solid phase extraction cartridge. The standard nitrovin was purified with crude nitrovin product by ethylene glycol monoethyl ether and identified by elemental analyzer. The limit of detection was 0.05 mg kg?1 and the limit of quatification was 0.2 mg kg?1 in feeds. The assay had satisfactory selectivity, recovery, linearity and precise repeatability and trueness. 相似文献
2.
Absorption transients at 254 nm have been observed in O3-O2 mixtures following laser irradiation at 9.64 μm. From analysis of these transients, we are able to determine vibrational relaxation rate constants (O3-O2 λ1?1/[O2] = (2560±370) Torr?1 S?1, λ2?1/[O2] = (640±50) Torr?1 S?1, and also a v1-v3 equilibration rate constant (O3-O3) of (1.5±1.0) × 106 Torr?1 S?1. 相似文献
3.
A rapid and sensitive method to assay baicalin in rat hippocampus was applied using a simple liquid-liquid extraction technique followed by high-performance liquid chromatography. Baicalin and the internal standard, 4-nitro-benzoic acid, were extracted twice from the homogenized solution with acetonitrile and after centrifugation the combined extracts were evaporated. To the remaining residue 0.1 mL of methanol were added to obtain the sample solution. A 10 μL volume of sample solution was injected onto HPLC for analysis carried out on a Zorbax SB-C18 column using a mobile phase of methanol–water-H3PO4 (45:55:0.2, v/v/v, pH 3.0) at 277 nm with a UV detector. The calibration curve for baicalin was linear over the concentration range of 0.05–1.6 μg mg?1 in hippocampus. Recoveries were reasonable for routine analyses (>88%) and the LOD and LOQ ranged from 0.006 to 0.009 μg mg?1 and 0.015 to 0.035 μg mg?1, respectively. The coefficient of variation of the assay precision was less than 5.9%, and the accuracy exceeded 98%. The method was applied to determine the time course of baicalin in rat hippocampus, following the intravenously administration of flavonoids from Scutellariae Radix extract at 90 mg kg?1 of baicalin to a male Wistar rat. This method provides a very simple, sensitive, and accurate way to determine baicalin concentrations in rat hippocampus. 相似文献
4.
Determination of Levamisole in Sheep Muscle Tissue by High-Performance Liquid Chromatography and Photo Diode Array Detection 总被引:1,自引:0,他引:1
A high-performance liquid chromatographic method for the determination of levamisole (LVM) residues in sheep muscle tissue
is described. LVM was extracted with ethyl acetate under alkaline conditions and cleanup was performed by liquid-liquid partition
between organic-basic and organic-acid medium. Finally, levamisole was back extracted with chloroform carefully transferred
into a clean glass vial and evaporated to dryness at 50 °C under a gentle stream of nitrogen. The remaining dry residue was
dissolved in the mobile phase used, filtered and an aliquot was injected automatically into the chromatograph for analysis.
Chromatography was performed on a Zorbax?SB-C18 column at 50 °C and detection by a PDA detector monitored at λmax 220 nm. The mobile phase was a mixture of 0.1 % trifluoroacetic acid (v/v) pH 2.0 and acetonitrile-methanol 3 : 2 (v/v) in a combination of 30 : 70 (v/v) and a flow rate of 1.0 mL min−1, delivered isocratically. This analytical method was validated by assessing recovery efficiency using spiked muscle tissue
samples with standard solutions in methanol at four fortification levels of 1/2 MRL, 1 MRL, 2 MRL and 4 MRL and five times
for each concentration (n = 5). Mean recovery (R%) achieved for muscle tissue was 75.65 ± 2.74% with an acceptable Relative Standard Deviation RSD%
= 10.4. The same method was used also for the analysis of kidney, liver and fat (perirenal) and the recoveries found were
70.25 ± 1.07% (RSD% = 1.52), 72.37 ± 3.6% (RSD% = 4.97) and 69.44 ± 2.22% (RSD% = 3.19), respectively. The limit of detection
(LOD) for muscle tissue was found to be 2.0 μg kg−1 and the limit of quantification (LOQ) 5.0 μg kg−1.
Revised: 4 and 24 January 2006 相似文献
5.
A. Savaşer A. Karataş Y. Özkan N. Yüksel S. A. Özkan T. Baykara 《Chromatographia》2004,59(9-10):555-560
A simple, rapid, specific, sensitive HPLC method has been developed for the determination of piroxicam in the tablet dosage form and in human plasma. The method totally eliminates solvent extraction and time-consuming separation procedures. Plasma proteins were precipitated by addition of 3:1 (v/v) acetonitrile-methanol, ZnSO4, and MgSO4 and the supernatant was injected directly on to a 250 mm × 4.6 mm, 5 μm particle Spherisorb analytical column. Acetonitrile-methanol-0.04 mol L?1 KH2PO4, 40:10:50 (v/v); pH 3.8, was used as mobile phase. The drug was detected by UV detection at 330 nm. The response was linear over the range of 0.01–10 μg mL?1 and 0.025–5 μg mL?1 in mobile phase and human plasma samples, respectively. The proposed method was used without interference from the endogenous substances, for determination of piroxicam in plasma samples obtained from healthy volunteers. The results revealed that the method would be useful in monitoring plasma levels of the drug during pharmacokinetic studies. Assay of piroxicam in its dosage forms for quality-control purposes could also be performed successfully by use of this method. 相似文献
6.
A method for the determination of iodate was developed by reversed-phase high-performance liquid chromatography with UV detection. Iodate was converted to iodine, which was separated from the matrix using a reversed-phase Ultrasphere C18 column (250 × 4.6 mm, 5 μm) with methanol-1 mmol L?1 H3PO4 (20:80, v/v) as mobile phase at 1.00 mL min?1 and UV detection at 224 nm. The calibration graph was linear from 0.05 μg mL?1 to 5.00μg mL?1 for iodine with a correlation coefficient of 0.9994 (n=7). The detection limit was 0.01 μg mL?1. The method was successfully applied to the determination of iodate in iodized salt. The recovery was from 96% to 101% and the relative standard deviation was in the range of 1.5% to 2.9%. 相似文献
7.
Weijie Deng Xiangnian Zhang Zhiping Sun Jilin Yin Zheng Zhou Liping Han Shujin Zhao 《Chromatographia》2012,75(11-12):629-633
A new and simple high-performance liquid chromatography with evaporative light scattering detector method for the determination of Kryptofix 2.2.2 (K-222) in the radiopharmaceuticals of 2-deoxy-2-[18F]fluoro-d-glucose ([18F]FDG) and 3′-deoxy-3′-[18F]fluorothymidine ([18F]FLT) was developed. A C18 column was used and the mobile phase was 10?% (v/v) methanol and 90?% (v/v) water (0.1?% trifluoroacetic acid, v/v) at a flow rate of 0.2?mL?min?1. The drift tube temperature was 40?°C. The pressure of nebulizing gas (N2) was 3.0?bar. The gain was 10. Good separation of K-222 from main related substances could be achieved. Excellent linearity (r 2?=?0.9995) was obtained over the range of 5–100?μg?mL?1. The precision ranged from 0.68 to 5.16?% (RSD) and the accuracy ranged from ?3.05 to 2.62?% (RE). The limit of detection was 2?μg?mL?1. This method offers simple, rapid and quantitative detection of K-222, thus making it acceptable for routine determination. 相似文献
8.
Hua Kuang XiaoLin Hou Hong Miao Gong Zhang JianZhong Shen 《International journal of environmental analytical chemistry》2013,93(6):423-437
Two series of haptens including 3-phenoxybenzoic acid (PBA) and 3-(2-chloro-3, 3,3-trifluoroprop-1-enyl)-2,2-dimethylcyclo-propanecarboxylic acid (CF3MPA) were used to prepare immunogens through attachment of 4-C or 6-C handles. Class selective antibodies were produced by immunising rabbits. Ab502 showed the highest reactivity towards tau-fluvalinate (IC50 1.3 ng mL?1), λ-cyhalothrin (IC50 2.3 ng mL?1), cyfluthrin (IC50 2.2 ng mL?1) and fenpropathrin (IC50 18.5 ng mL?1) among the antibodies in a competitive ELISA. The effects of methanol, pH and salt concentration were optimised for maximum efficiency of the ELISA (Enzyme-Linked ImmunoSorbent Assay). Ab502 (1:80000)/2-OVA-1(0.2 µg mL?1) was chosen for ELISA optimisation. Finally, 0.05 M phosphate buffered saline (PBS) at pH 6.5 containing 30% methanol (v/v) was used to dilute the standards. Target analytes in honey samples were extracted with ethyl acetate by sonication. The samples were spiked with three different concentrations of each compound (tau-fluvalinate, 0.5 ng g?1, 3 ng g?1, 12 ng g?1; λ-cyhalothrin and cyfluthrin 1 ng g?1, 5 ng g?1, 65 ng g?1). The recoveries were 36–59% at the lowest spiking concentration and 61–81% at the higher concentration. This assay might be useful to screen pyrethroid residues in honey or other matrix. 相似文献
9.
Hua Kuang Hong Miao Xiao Lin Hou Yun Feng Zhao Jian Zhong Shen Chuan Lai Xu Yong Ning Wu 《Chromatographia》2009,70(5-6):995-999
A method was developed to determine six pyrethroids (tau-fluvalinate, fenpropathrin, λ-cyhalothrin, cyfluthrin, α-cypermethrin and deltamethrin) in pork muscle by immunoaffinity column cleanup and gas chromatography-electron capture detection. Spiked pork muscle samples at 5, 20, 50 μg kg?1 were extracted with petroleum spirit-diethyl ether (1:1, v/v). Fat was eliminated by liquid–liquid partition between acetonitrile and petroleum spirit. An immunoaffinity column (IAC) was used for further cleanup. The IAC column was prepared by coupling the polyclonal antibodies to the protein A sepharose gel and the resulting affinity gel columns were sufficiently stable for multiple reuse. Target compounds were adsorbed at pH 7.4 and after extensive washing, eluted with 3 mL methanol. Recoveries of the six pyrethroids were typically >70%. The detection limit was 2 μg kg?1 for λ-cyhalothrin and α-cypermethrin and 5 μg kg?1 for cyfluthrin, deltamethrin, fenpropathrin and tau-fluvalinate. Repeat analyses of pork muscle samples showed good repeatability. The method was applied to detect residues in meat samples. 相似文献
10.
A sensitive and specific ELISA for determining a residue marker of three quinoxaline antibiotics in swine liver 总被引:1,自引:0,他引:1
Linli Cheng Jianzhong Shen Zhanhui Wang Wenxiao Jiang Suxia Zhang 《Analytical and bioanalytical chemistry》2013,405(8):2653-2659
Methyl-3-quinoxaline-2-carboxylic acid (MQCA) is a possible residue marker for three quinoxaline veterinary medicines (olaquindox, mequindox, and quinocetone). The wide application of mequindox/quinocetone or the illegal use of olaquindox leads to MQCA residue in animal’s original food, thereby threatening the safety of human food. The indirect competitive enzyme-linked immunosorbent assay (IC-ELISA) with a specific coating antigen and monoclonal antibody (MAB) was established and optimized for detecting MQCA in swine liver. Samples were acidified with 2 mol?l?1 hydrochloric acid, extracted with ethyl acetate–hexane–isopropanol (8?+?1?+?1, v/v/v) and then detected by IC-ELISA. The logarithm correlation of standards to OD values ranged from 0.2 to 200 μg?l?1, with IC50 of 6.46 μg?l?1. Negligible cross-reactivity happened to five quinoxaline antibiotics (olaquindox, mequindox, quinocetone, carbadox, and cyadox) and the metabolite of carbadox and cyadox (quinoxaline-2-carboxylic acid). When spiked with 1 to 100 μg?kg?1 of MQCA, the recoveries ranged from 85.44 to 100.02 %, with the intra-assay coefficient of variation (CV) of 6.64–10.57 % and inter-assay CV of 7.29–10.88 %. The limit of detection for MQCA was 1.0 μg?kg?1 in swine liver. Furthermore, incurred samples were detected by the IC-ELISA and then conformed by a reported LC/MS/MS method, it shown that there was good correlation between the two methods. All these results indicated that the IC-ELISA method is appropriate for surveillance MQCA residue in animal tissues. Figure
Synthesis route of 2-acrylic-1,4-binitrogen-quinoline combined to BSA(OVA) by active ester method 相似文献
11.
Cefuroxime is a broad-spectrum second-generation bactericidal cephalosporin antibiotic active against β-lactamase-producing strains. Anti-cefuroxime, the geometric isomer of cefuroxime, might be present in cefuroxime dosage forms as a process-related impurity and possible degradation product. In the work discussed in this paper a precise and sensitive micellar liquid chromatographic (MLC) method for stability testing of cefuroxime axetil and anti-cefuroxime axetil in tablets, using benzoic acid as internal standard, was developed and validated. MLC was performed on an XTerra C18 reversed-phase column at 50 °C with 8:92 (v/v) acetonitrile–20 mM sodium dodecyl sulphate, pH 2.5, as mobile phase at a flow rate of 1.5 mL min?1. Detection was at 280 nm. Under these conditions the retention time and retention factor were of 6.65 min and 4.57, respectively, for cefuroxime axetil and 11.45 min and 8.59, respectively, for anti-cefuroxime axetil, indicating that the compounds were well separated. RSD values for quantification of cefuroxime axetil and anti-cefuroxime axetil were 0.39 and 1.7%, respectively, indicating the precision of the MLC method was good. The method is sensitive—LOD=0.5 μg mL?1 and LOQ=1.5 μg mL?1 for anti-cefuroxime axetil—and reproducible, with good recovery values. 相似文献
12.
Riyazuddeen Dheeraj Kumar Sadaf Afrin 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2014,88(1):52-56
Densities of L-serine, L-isoleucine, L-glutamine in 1.5 mol kg?1 aqueous NaCl, and NaNO3 solutions have been measured for several molal concentrations of amino acids at temperatures from 298.15 to 323.15 K. The partial molar volumes (? v 0 ) of L-serine, L-isoleucine, and L-glutamine in 1.5 mol kg?1 aqueous NaCl/NaNO3 solutions have been computed using density data. The transfer partial molar volumes (Δtr? v 0 ) of L-serine, L-isoleucine, and L-glutamine from water to 1.5 mol kg?1 aqueous NaCl/1.5 mol kg?1 aqueous NaNO3 solutions have been determined at 298.15 K. The trends of variation of ? v 0 and Δtr? v 0 with change in temperature have been discussed in terms of ion-ion, ion-hydrophilic, and ion-hydrophobic interactions operative in solutions. 相似文献
13.
A liquid chromatographic method for the simultaneous determination of three flavonoids, scutellarin (SCU), isoscutellarein-8-O-glucuronide (ISO) and luteolin (LUT) in rat plasma was developed and validated. Following a single-step liquid–liquid extraction with ethyl acetate, the analytes and internal standard (IS) (rutin) were successfully separated on a Diamonsil C18 column using a mobile phase composed of acetonitrile (A)–0.2% phosphoric acid aqueous solution (B) (0–5 min, 20% A–29% A; 5–25 min, 29% A, v/v) at a flow rate of 1.0 mL min?1. The linear range was 0.044–2.20 μg mL?1 for SCU, 0.042–2.08 μg mL?1 for ISO, and 0.056–2.80 μg mL?1 for LUT, with the correlation coefficients of 0.9995, 0.9989 and 0.9963, respectively. The limit of quantification of SCU, ISO and LUT were 44, 41.6 and 56 ng mL?1, respectively. The accuracy of assay was between 88.4 and 103.0%. The inter-day and intra-day precisions (RSD) were less than 10.5%. The developed method was simple, rapid and applied successfully to study the pharmacokinetics of SCU, ISO and LUT after oral administration of the total flavonoids of Scutellaria barbata. 相似文献
14.
An extraction method based on matrix solid-phase dispersion was developed to determine carbofuran, pyrimethanil and tetraconazole in banana using gas chromatography–mass spectrometry. The best results were obtained using 2.0 g of banana, 1.0 g of silica as dispersant sorbent and n-hexane:ethyl acetate (1:4, v/v) as eluting solvent. The method was validated using banana samples fortified with pesticides at different concentration levels (0.05–2.0 mg kg?1). Average recoveries (four replicates) ranged from 68 to 111%, with relative standard deviations between 6.6 and 20.5%. Detection and quantification limits for banana ranged from 0.02 to 0.05 and 0.05 to 0.10 mg kg?1, respectively. 相似文献
15.
A method for determination of some biologically active penta- and nona-peptides under isocratic conditions in capillary liquid chromatography was developed. Separation system consisting of XTerra C18 stationary phase and mobile phase composed of a mixture of acetonitrile with 0.1% trifluoroacetic acid (TFA) and water with 0.1% TFA in the ratios 75/25 (v/v) and 85/15 (v/v) was suitable not only for a good resolution of enkephalin and vasopressin related peptides, respectively, but it also enabled separation of the respective biopeptides from other constituents of human urine. Calibration curves for the studied peptides were linear in the measured concentration range from 1.00 to 1.57×10?2 mg mL?1. The limit of detection and limit of quantification were in the range of units of μg mL?1 and tens of μg mL?1, respectively; slightly higher values were obtained for nonapeptides. Determination of certain biologically active peptides in urine can serve in future as a tool for diagnosis of various diseases, e.g. autism. 相似文献
16.
An analytical multiclass, multi-residue method for the determination of antibiotics in aquaculture products was developed and validated. A fast, cheap, and straightforward extraction procedure followed by liquid chromatography-tandem mass spectrometry analysis was proposed. This method covers 32 antibiotics of different classes, which are frequently used in aquaculture. Three different extraction procedures were compared, and the extraction with acetonitrile (0.1 vol. % formic acid) showed the best results. The selected extraction procedure was validated at four different fortification levels (10 μg kg?1, 25 μg kg?1, 50 μg kg?1, and 100 μg kg?1). Recoveries of the tested antibiotics ranged from 70 % to 120 %, with the relative standard deviation (RSD) of triplicates lower than 20 %. The limits of quantification (LOQ) ranged from 0.062 μg kg?1 to 4.6 μg kg?1, allowing for the analysis of trace levels of these antibiotics in aquaculture products. The method was applied to the analysis of selected antibiotics in fish and shrimp meat available in the Czech market. 相似文献
17.
Thitima Rujiralai Nirundorn Raekasin Wilairat Cheewasedtham Chonlatee Cheewasedtham 《Chemical Papers》2014,68(8):1041-1048
A method for extracting coenzyme Q10 (CoQ10) from Artemia was developed. 1 g of fresh Artemia was incubated with 75 % acetic acid at (30 ± 2)°C for 24 h, followed by three consecutive extractions with a mixture of 5 mL of hexane and 5 mL of ethanol, then analysis by a validated high-performance liquid chromatography with a diode-array detector. The calibration curve for CoQ10 was linear in a range of 1–50 μg mL?1. The limits of detection and quantification were 0.3 μg mL?1 and 1.1 μg mL?1, respectively. Mean recoveries were 94–100 % with a high precision of below 10 %. The method developed was found to be simple, efficient and the time required for releasing CoQ10 from Artemia was short. The method provides not only low energy consumption but is also practical for industrial applications. 相似文献
18.
Jian-Jun Zou Hong-Wei Fan Da-Qing Guo Ying-Bin Li Song Lin Yu-Bing Zhu Cui-Xia Yu Jie Zhou Jiang-Hui Liu Yun-Fang Hu 《Chromatographia》2009,70(11-12):1581-1586
A sensitive and specific liquid chromatography-tandem-mass spectrometry method was developed and validated for the simultaneous determination of clopidogrel and its carboxylic acid metabolite (SR26334) in human plasma using nateglinide and pioglitazone as internal standards. Analytes were extracted from 0.50 mL of plasma using diethyl ether–n-hexane (4:1, v/v). Chromatographic separation was performed on a Teknokroma C18 column with a mobile phase of methanol–water (containing 0.1% formic acid) (80:20, v/v) at a flow rate of 0.20 mL min?1 within 5.6 min. Linearity was established over the concentration range of 0.005–5 ng mL?1 for clopidogrel and 20–2,500 ng mL?1 for SR26334. Intra- and inter-batch standard deviations were less than 9.2% and the accuracy of this assay was found to fall within an acceptable range ≤10.0%. The method was successfully applied to the therapeutic drug monitoring of clopidogrel. 相似文献
19.
Two new, rapid, precise, accurate and specific chromatographic methods were described for the simultaneous determination of olmesartan medoxomil and hydrochlorothiazide in combined tablet dosage forms. The first method was based on reversed phase liquid chromatography using an Eurosphere 100 RP C18 column (250 × 4.6 mm ID, 5 μm). The mobile phase was methanol–0.05% o-phosphoric acid (60:40 v/v) at a flow rate of 1.0 mL min?1. Commercially available tablets and laboratory mixtures containing both drugs were assayed and detected using a UV detector at 270 nm. The second method involved silica gel 60 F254 high performance thin layer chromatography and densitometric detection at 254 nm using acetonitrile–ethyl acetate–glacial acid (7:3:0.4 v/v/v) as the mobile phase. Calibration curves ranged between 200–600 and 125–375 ng spot?1 for olmesartan and hydrochlorothiazide, respectively. 相似文献
20.
1,5-Bis(2,3-dihydroxyphenylmethylene)thiocarbohydrazone was synthesized; its ionization constants are reported. A procedure is described for the spectrofluorimetric determination of 5–540 ng ml?1 zinc in 60/40 (v/v) ethanol/water medium, acetate-buffered to apparent pH 6.5 (λex=400 nm, λem=508 nm). Interferences were evaluated and the procedure was applied with good results to the determination of zinc in potable waters (0.3–3 μg ml?1) and lubricating oils. 相似文献