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1.
AbstractA new fluorescence probe 1 for sulfur dioxide derivatives has been developed which acts through nucleophilic addition of the derivatives and shows high stability, specificity, and sensitivity. In the presence of SO 2 derivatives, the fluorescence intensity of probe 1 significantly decreases within a short time period of 40?s, along with a low detection limit of 0.32?µM. Fluorescence imaging capability of probe 1 was also investigated, showing clear detection of SO 2 derivatives in living cells. The results indicate that this probe has a great potential for the detection of SO 2 derivatives in broad biological and relevant samples. 相似文献
2.
Abstract The nonspecific binding of rabbit anti-ferritin Fab′-B-D-galactosidase conjugate to rabbit anti-ferritin IgG-coated polystyrene balls in two-site enzyme immunoassay for ferritin was reduced to various extents by the presence of nonspecific rabbit F(ab′) 2, inactive β-D-galactosidase and related substances with only small decreases in the specific binding, and the detection limit of ferritin was improved up to 10-fold. The use of nonspecific F(ab′) 2, inactive β-D-galactosidase and related substances was suggested to be useful for improving the detection limit of other antigens. 相似文献
3.
A simple colorimetric chemosensor 1 was developed for the sequential detection of Cu 2+ and S 2?. Sensor 1 could rapidly detect Cu 2+ by an obvious color change from colorless to yellow. The binding mode of 1 to Cu 2+ was determined to be a 1:1 complexation stoichiometry through Job plot and ESI-mass spectrometry analyses. The sensing mechanism of Cu 2+ by 1 was proposed by theoretical calculations. Importantly, the detection limit for Cu 2+ was found to be 0.12 μM, which was much lower than the recommended value (31.5 μM) of the World Health Organization (WHO). Additionally, 1 could detect and quantify Cu 2+ in real water samples. Moreover, the resulting 1-Cu 2+ complex could be used as a highly selective colorimetric sensor for S 2? in the presence of various anions without any interference. The detection limit for S 2? was determined to be 1.66 μM, which was much lower than the guideline (14.8 μM) recommended by WHO in fresh water. 相似文献
4.
Abstract A new optical detector box for a commercially available detector for the atomic fluorescence detection of mercury was redesigned and tested. After optimisation of the new set-up the limit of detection was improved 13 fold. It was not feasible to use a hydrogen argon diffusion flame for the speciation of mercury, because of strong fluorescence signal quenching. 相似文献
5.
Abstract The suitability of HPLC (normal and reversed phase adsorption) with UV or post-column reaction detection for the analysis of organomercurials was investigated systematically. The separation of organomercurials is best carried out on a reversed phase system with a C-8 bonded phase material as the stationary phase and acetonitrile-aqueous sodium bromide mixtures as the mobile phase. The precision and detection limit of the method and the efficiency of the extraction procedure were established. For the alkylmercury compounds the lowest limit of detection (80ppb) was obtained with the dithizone reaction detection and for the phenylmercury compounds with UV detection (60ppb). A chromatogram of a spiked fish (2ppmHg) and a river water sample (50ppbHg) is shown. 相似文献
6.
Abstract A chemiluminescence - high performance liquid chromatography (CL-HPLC) system was developed for the hydroperoxide-specific detection of phosphatidylcholine hydroperoxide. In this system, chemiluminescence detector was equipped with normal phase HPLC. Luminol-cytochrome c solution was used as the hydroperoxide-specific luminescent reagent. A detection limit of 7 nmol hydroperoxide-O 2 of phosphatidylcholine hydroperoxide could be achieved. 相似文献
7.
Abstract A method is described for the determination of traces of arsenic in industrial ZnSO 4 solutions for electrolysis by cathodic stripping voltammetry. The limit of detection is of the order of 1 ppb. 相似文献
8.
ABSTRACTA new fluorescent-colorimetric chemosensor L has been synthesised by Schiff base condensation reaction between 1,8-diaminooctane and 4-nitro-benzaldehyde in very good yields. Its photo-luminescent properties and selective detection properties for hydrazine have been examined. The synthesised chemosensor exhibited highly selective fluorescence on-off response for hydrazine amongst a wide range of different metal cations, anions and amines, along with the bare eye colour change from colourless to yellow based on intermolecular hydrogen-bond interaction. The limit of detection of the chemosensor L was estimated as 9.77 × 10 ?8 M or 3.12 × 10 ?6 g L ?1 for hydrazine which is extremely below the limit set by the World Health Organization (WHO) and the binding stoichiometry was proposed to be 1 : 2 based on 1H NMR spectroscopic techniques and the Job’s plot analysis. The proposed sensing mechanism is the hydrogen-bonding interaction which has further been established by Density Functional Theory (Functional Density Theory (DFT)) studies. This recognition feature of sensor L makes it an efficient chemosensor for hydrazine detection in different water samples. 相似文献
9.
Abstract 5-Fluorouracil in plasma was determined by extraction with methyl isobutyl ketone, evaporation of the ketone, and reverse phase high performance liquid chromatography of the evaporation residue. With UV detection at 280 nm the lower limit of detection is 10.0 ng/ml and interfering peaks eliminated. The method is highly reproducible. 相似文献
10.
A simple, suitable reverse phase liquid chromatographic method was developed for simultaneous determination of andrographolide (1) and dehydroandrographolide (2) in chicken plasma after orally administrating the ultra-fine powder of Andrographis paniculata. Plasma samples were extracted with ethyl acetate. Analysis of the extract was performed on a reversed-phase C18 column with gradient eluent composed of acetonitrile and 0.5% acetic acid. The flow rate was kept at 1 mL min−1 and the detection wavelength was set at 225 and 255 nm for 1 and 2, respectively. All calibration curves showed good linear regression (R ≥ 0.9991). The good precision and recoveries with intra-day and inter-day were 3.2–8.7% and 91.1–98.4%, respectively. The limit of detection was 0.016 µg mL−1 and the limit of quantitation was 0.040 µg mL−1 for the target analytes. This validated method has been successfully applied in the pharmacokinetics study of 1 and 2 after orally administrating the Andrographis paniculata ultra-fine powder to chicken. 相似文献
11.
Abstract A simple method involving ion chromatography with ultraviolet detection (IC-UV) is applied to the determination of benzoic acid in atmospheric samples. The detection limit is 10 nanograms. Validation and interference studies are described. The application of the IC-UV method to other aromatic acids including nitrophenols is briefly discussed. 相似文献
12.
Abstract A colour reaction has been studied for resin bead detection of phenylhydrazine with copper(II) nitrate. The interaction of phenylhydrazine with periodic acid has been studied for its spectrophotometric determination. The detection limit is 10μg. Beer's law is obeyed in the concentration range 0.1 to 3.0 mg of phenylhydrazine. 相似文献
13.
Two types of rhodamine–naphthalimide sensors 1a–1c and RND with different polyamine linkers and terminal chains were designed and synthesized for different ratiometric detection of Fe(III) or Hg(II). The fluorescent properties including response time, pH effect, selectivity, anti-interference, fluorescence titration and reproducibility were investigated and compared in details. Sensor RND possessing two recognition groups of rhodamine and 1-(pyridin-2-ylmethyl)piperazine displayed good response and selectivity to Hg(II) with a detection limit of 1.72 μmol/L, whereas 1a–1c with piperidine instead of 1-(pyridin-2-ylmethyl)piperazine showed quite different recognition to Fe(III) and the detection limit of 1b was the lowest (1.92 μmol/L). The Hg(II)/Fe(III) chelation-induced dual/single recognition mechanisms as well as the structure–fluorescence properties relationships (SFPRs) were discussed in detail with the aid of quantum chemical density functional theory (DFT) calculations. Through adjusting the linker and introducing other recognition groups to rhodamine- naphthalimide system, novel sensors with selective recognition of different metal ions should be achieved. 相似文献
14.
Abstract A recent outbreak of poisoning resulting from the consumption of cultured blue mussels ( Mytilus edulis L.) from a localized area in Eastern Canada has been attributed to the presence of domoic acid ( 1), a relatively rare neurotoxic amino acid, previously found only in some algae of the family Rhodomelaceae. Studies on aqueous extracts of shellfish tissue indicated that the toxin and several of its isomers could be separated (and isolated in sufficient amounts for subsequent structural identification) by reversed-phase high-performance liquid chromatography (HPLC) with ultraviolet (UV) diode array detection (DAD). Aqueous acetonitrile containing 0.1% v/v trifluoroacetic acid was used as mobile phase. As the retention time and characteristic UV absorption spectrum of 1 (λ max = 242 nm) permit unequivocal identification, the HPLC-DAD procedure was refined with a microbore column to provide a rapid (5 min), sensitive (0.3 ng detection limit) and reproducible assay method for the determination of 1 in shellfish tissue. Extraction was accomplished by boiling homogenized shellfish tissue for 5 min with distilled water. Extracts were taken through an octadecylsilica solid phase extraction clean-up prior to HPLC. This method has been applied to a variety of shellfish and phytoplankton samples. BRIEF Reversed-phase HPLC with ultraviolet diode array detection was used to analyze shellfish tissue and phytoplankton extracts for domoic acid. A rapid (5 min) and sensitive (0.3 ng detection limit) assay is presented. 相似文献
15.
Abstract A quantitative high pressure liquid chromato-graphic (HPLC) assay has been developed for the determination of glutamic acid decarboxylase (GAD) activity in subregions of rat brain. GAD activity was determined indirectly by measurement of gamma-aminobutyric acid (GABA). Fluorimetric detection was made possible by derivatization with ortho-phthalaldehyde and the limit of detection was 11 ng GABA. 相似文献
16.
Abstract Limit of detection criteria in analytical chemistry are regularly specified in terms of the distribution of the measured blank response. The consequences of an analytical blank response with a negligible distribution of measured values on the calculation and significance of limit of detection criteria receive scarce attention. A consideration of a hypothetical analytical methodology where the blank response is zero and the distribution of blank values is negligible is described. The impact of this situation on the traditional limit of detection criteria and on calibration relationships is discussed in detail. A simple, empirical method of estimating indicative method detection limits based on whole‐method repeatability is proffered. This model has been validated with experimental data. 相似文献
17.
Abstract A highly sensitive and specific detection method has been developed for iron with a limit of detection ~ 0.0001 mg per 0.02 ml on the beads of siroomium(IV) arsemophosphate cation exchanger, utilizing its adserptie-iem-exchange properties and the complex forming ability of 1, 10-phenanthroline. A mechanism has also been proposed tentatively on the basis of some experimental observations and theoretical considerations. 相似文献
18.
Abstract A high performance liquid chromatographic (HPLC) method has been developed to determine riboflavin in food samples. A reverse phase C 18 column with ultraviolet detection was employed. Sample preparation included acid and enzimatic hydrolysis, followed by purification on Florisil and Sep-Pak cartridges. Recoveries of 98% were obtained. A detection limit of 0.4 ng/injection has been achieved. 相似文献
19.
ABSTRACT Glassy Carbon Electrodes coated with stearic acid provide an amperometric sensor for detection of paraquat, the active ingredient of the herbicide Gramoxone. The linear dynamic range of the sensor for Paraquat is 1.02 × 10 ?3 mol dm ?3 to 1.02 × 10 ?2 mol dm ?3 with the minimum detection limit 6.37 × 10 ?4 mol dm ?3. 相似文献
20.
A new receptor 3-((2-(1H-benzo[ d]imidazol-2-yl)phenylimino)methyl)benzene-1,2-diol ( 1) was synthesised and developed as a highly selective fluorescent chemosensor for the detection of Hg 2+ in semi-aqueous media. The fluorescence of receptor 1 was dramatically and selectively quenched on complexation with Hg 2+ ion with the detection limit down to 0.20 μM. The developed sensor was successfully applied for the determination of Hg 2+ content in water samples. Density Functional Theory (DFT) calculations were performed to study the mechanistic behaviour behind the binding of Hg 2+ with receptor 1. 相似文献
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