A new method for the titrimetric determination of the ferricyanide ion

The direct titration of ferricyanide ions with the mercurous-thiocyanate system is studied, the influence of pH, thiocyanate concentration, time and temperature being considered. The standard deviation of the proposed method is 0.26 per cent.     

A chemiluminescence flow injection system for nitrite ion determination

A chemiluminescence system is described for the determination of nitrite ion based on new designs for an ozone generator, liquid-gas separator and chemiluminescence reaction cell. The method is based on the gas-phase chemiluminescence reaction between ozone and nitric oxide, which is generated from the reduction of nitrite with iodide in sulfuric acid solution. The efficiency of the system was evaluated by investigation of the analytical performance characteristics of the system for nitrite determination in batch and flow injection procedures. Under optimal conditions, the chemiluminescence response of the system was linear against the nitrite concentration over the range 1 to 1 × 10⁴ ng ml^?1 in the batch procedure and 10 to 5 × 10³ ng ml^?1 in the flow injection procedure, with detection limits of 1 and 10 ng ml^?1, respectively. The method is highly selective and allows for the determination of nitrite in the presence of high concentrations of several cationic, anionic and nitrogen containing species. It has been successfully applied to the analysis of nitrite in natural water and soil extracts.     

A new chemiluminescence reagent for the determination of ruthenium

A new reagent proflavine-N, N, N', N'-tetraacetic acid (PTA) synthesized in our laboratory has been found useful as a chemiluminescence reagent for the determination of ruthenium (Ru) in pH 2.5 sulfuric acid solution containing acetone, it can be oxidized catalytically by hydrogen peroxide. With Ru(III) as catalyst, it emits light selectively. The linear range is between 2.0 x 10(-8) and 2.0 x 10(-5) g/ml. The detection limit and the recovery rate of the method are 1.0 x 10(-9)g/ml and 96.0-102%, respectively. The method has been satisfactorily applied to determine trace Ru(III) in synthesized sample.     

A new chemiluminescence system for determination of cobalt

The chemiluminescence of the reaction of tartaric acid with hydrogen peroxide in the presence of Co(II) in alkaline buffer media has been examined. The maximum emission wavelength is 460 nm. The kinetic curve of the chemiluminescence system has been modelled with a computer, and the reaction conditions have been optimized. Foreign ions, such as Fe(II), Cr(III) and Mn(II), interfere when present in more than 10-fold ratio to Co(II), but several ions can be tolerated when present in higher ratios to Co(II). The concentration range of linear response is from 3.5 x 10(-9) to 2.0 x 10(-6) g/ml, and the detection limit is 4 x 10(-11) g/ml. The procedure has been satisfactorily applied to determine trace cobalt in human blood serum.     

A spectrophotometric method for the determination of nickel

A photometric method for the determination of nickel using versene is described. Up to 20 mg of nickel can be determined with a maximum deviation of ± 0.10 mg. The effect of interfering elements, concentrations, accuracy and limitations of the method are discussed.     

流动注射化学发光法测定盐酸羟苄唑

基于在碱性条件下盐酸羟苄唑能够与鲁米诺产生化学发光的现象,建立了流动注射化学发光测定盐酸羟苄唑的新方法。盐酸羟苄唑的浓度在8×10-7~1×10-4mol/L范围内与化学发光强度呈良好的线性关系,方法的(3σ)检出限为3×10-7mol/L,对1×10-5mol/L的盐酸羟苄唑连续11次测定的相对标准偏差为1.7%,回收率为96%~103%。已用于滴眼液中盐酸羟苄唑的测定。     

Rapid chemiluminescence method for the determination of iodate traces

A rapid chemiluminescence method for the determination of iodate has been developed, based on the reaction with an excess of iodide in acidic solutions, gas extraction of the iodine formed and detection in the stream of carrier gas by alkaline luminol solution. The limit of detection for IO^– ₃ is 0.7 g/l. The time required for analysis is 2 min.     

Peroxidase-catalysed luminol chemiluminescence method for the determination of glutathione

A luminol chemiluminescence (CL) method was developed for the determination of glutathione (GSH). GSH was indirectly determined by measuring the amount of hydrogen peroxide formed during the Cu(II)-catalysed oxidation of GSH with oxygen. The amount of hydrogen peroxide formed was continuously measured using the Arthromyces ramosus peroxidase-catalysed luminol CL reaction. The CL intensities at maximum light emission were linearly correlated with the concentration of GSH over the range 7.5 x 10(-7)-3.0 x 10(-5) M. The detection limit for GSH was about 10 times better than that of the spectrophotometric method using Ellman reagent.     

A sensitive chemiluminescence method for the determination of cysteine based on silver nanoclusters

We have developed a sensitive chemiluminescent (CL) assay for cysteine. It is based on the use of water-soluble and fluorescent silver nanoclusters (Ag NCs) which are found to be able to strongly enhance the weak CL signal resulting from the redox reaction between Ce(IV) ion and sulfite ion. This enhancement is inhibited by cysteine under appropriate conditions. Taking advantage of this specific CL inhibition, a novel CL method for the sensitive and selective detection of cysteine was developed. This effect is interpreted in terms of an electronic energy transfer from excited state intermediate sulfur dioxide (originating from the CL reaction between Ce(IV) and sulfite ions) to the Ag-NCs. The latter become electronically excited and thus can act as a new source of emission. The method was applied to the determination of cysteine in the range from 5.0?nM to 1.0?μM, with a detection limit at 2.5?nM (S/N?=?3).

Flow-injection-enhanced chemiluminescence method for the determination of four anticancer drugs

Novel chemiluminescence (CL) reaction systems were established for the determination of anticancer drugs, including adriamycin (ADM), hydroxycamptothecin (HCPT), mitomycin (MMC), and fluorouracil (5-FU). The formaldehyde-sensitized CL emission mechanism was developed for four systems by comparing the fluorescence emission and CL spectra. For ADM-KMnO₄-HNO₃, HCPT-KMnO₄-H₂SO₄, MMC-KMnO₄-HNO₃, and 5-FU-KMnO₄-HCl systems, the illuminant was a singlet state bimolecule oxygen, ¹O₂ ¹O₂(¹Δ_g ¹Δ_g), which was formed from ¹O₂ (¹Δ_g) produced in the reaction system. The illuminant emits CL spectra at 539 or 549 nm. The presence of formaldehyde can sensitize CL emission because it may accelerate the generation of ¹O₂ (¹Δ_g). The optimum conditions for the CL emission were chosen. The relationships between the relative CL intensity and the concentration of the studied analytes are linear with the correlation coefficients in the range of 0.9959–0.9989. The proposed four enhanced CL systems provide a good linearity, a high sensitivity, precision, and the potential capability for the determination of anticancer drugs in biological samples. The text was submitted by the authors in English.     

Simple and convenient chemiluminescence method for the determination of melatonin

A simple and convenient chemiluminescence (CL) method for the determination of melatonin is reported. It is based on the observation that melatonin can greatly enhance the ultra-weak CL between H₂O₂ and acetonitrile in alkaline solution. Light emission is intense and long-lived, and even with a simple setup, a high sensitivity could be achieved. The log-log linear range was 250 nM-250 μM with a 3σ detection limit of 100 nM. Singlet oxygen is suggested to be produced by the reaction between H₂O₂ and acetonitrile and is responsible for the CL of melatonin. As a preliminary application, this simple method has been successfully applied into the determination of melatonin in health-foods.     

A new semi-empirical kinetic method for the determination of ion exchange constants for the counterions of cationic micelles

A new method, based upon semi-empirical kinetic approach, for the determination of ion exchange constant for ion exchange processes occurring between counterions at the cationic micellar surface is described in this review article. Basically, the method involves a reaction kinetic probe which gives observed pseudo-first-order rate constants (k_obs) for a nucleophilic substitution reaction between the nonionic and anionic reactants (R and S) in the presence of a constant concentration of both reactants as well as cationic micelles and varying concentrations of an inert inorganic or organic salt (MX). The observed data (k_obs, versus [MX]) fit satisfactorily (in terms of residual errors) to an empirical equation which could be derived from an equation explaining the mechanism of the reaction of the kinetic probe in terms of pseudophase micellar (PM) model coupled with another empirical equation. This (another) empirical equation explains the effect of [MX] on cationic micellar binding constant (K_S) of the anionic reactant (say S) and gives an empirical constant, K_X/S. The magnitude of K_X/S is the measure of the ability of X⁻ to expel S⁻ from a cationic micellar pseudophase to the bulk aqueous phase through ion exchange X⁻/S⁻. The values of K_X/S and K_Y/S (where Y⁻ is another inert counterion) give the ion exchange constant, K_X^Y (= K_X/K_Y where K_X and K_Y represent cationic micellar binding constants of X⁻ and Y⁻, respectively). The suitability of this method is demonstrated by the use of three different reaction kinetic probes and various MX.     

A new method for electrostatic ion deflection

A new approach to electrostatic ion deflection is described where an electrostatic particle guide (EPG) operating with reversed polarity is used to deflect ions in a cylindrical geometry about the axis of a time-of-flight mass spectrometer. The method has advantages over the standard parallel-plate deflector geometry in that it is more effective in deflecting ion beams that have a significant radial velocity component. The device is being used in ²⁵²cs Cf plasma desorption mass spectrometry (²⁵²cs Cf -PDMS) experiments in an on/off mode to record neutral particle spectra and in a synchronized pulsed mode to reduce the magnitude of the uncorrelated background in the time-of-flight spectrum. Radial distribution functions have been measured for various EPG voltages. Its use as a background suppression technique is demonstrated by using the ²⁵²cs Cf-PDMS spectrum of insulin. (28-36)     

A lanthanide sensitized chemiluminescence method of flow-injection for the determination of ulifloxacin and prulifloxacin

A lanthanide sensitized chemiluminescence method of flow-injection was developed for the determination of a new fluoroquinolone, ulifloxacin (UFX), and its prodrug prulifloxacin (PUFX). The proposed method was based on the remarkable chemiluminescence enhancement effect of UFX (PUFX) on KMnO₄−Na₂S₂O₄−Ln(III). Tb(III) ion was chosen from lanthanides because it showed the best sensitizing effect. Under optimized experimental conditions, the relative chemiluminescence intensity was in linear relationship with UFX and PUFX concentrations in the ranges of 1.0 × 10⁻⁸ − 5.0 × 10⁻⁶ M and 9.0 × 10⁻⁹ − 5.0 × 10⁻⁶ M, respectively. The minimum detectable value and relative standard deviation were 5.5 × 10⁻⁹ M, 1.5% for UFX and 7.0 × 10⁻⁹ M, 2.9% for PUFX, respectively. The proposed method was applied to the determination of UFX in spiked human serum and urine, and of PUFX in tablets with satisfactory results. The possible mechanism of chemiluminescence was also proposed. The text was submitted by the authors in English.     

A modified dimethylglyoxime method for the determination of nickel in sea water

A colorimetric dimethylglyoxime (DMG) method for the determination of nickel in sea water was studied in detail, and improved through close control of experimental conditions. For a maximum precipitation of 90% of the nickel a minimum period of 7 days was necessary between treatment with sodium carbonate and filtration. A salt effect resulted from: (1) a gain in absorbance due to soluble ions not precipitated by sodium carbonate, which increased with increasing salt concentration, (2) an offsetting loss in absorbance due to incomplete precipitation of nickel. The transition 3d ions precipitated by sodium carbonate exerted no discernible effect on the absorbance.A procedure is recommended by which a relative standard deviation of 0.7% was achieved. Consistent recovery yields of 97% were obtained from samples of sea water spiked with nickel collected over a period of several months.     

流动注射协同化学发光法测定盐酸多巴胺

基于在碱性介质中,盐酸多巴胺和单宁协同促进KIO4氧化鲁米诺反应而产生发光,建立了流动注射化学发光法测定盐酸多巴胺的新方法。该方法测定盐酸多巴胺的线性范围为2.0×10-10～6.0×10-8g/mL,检出限为1.17×10-10g/mL,对于8.0×10-10g/mL盐酸多巴胺测定11次的相对标准偏差为1.92%。方法可应用于盐酸多巴胺注射液和尿样中盐酸多巴胺的测定。     

流动注射化学发光法测定甲磺酸帕珠沙星

在酸性条件下甲磺酸帕珠沙星（Pazufloxacin Mesylas）对Ce（Ⅳ）-Na2SO3弱化学发光体系具有很强的增敏作用,据此建立了流动注射化学发光法测定甲磺酸帕珠沙星的新方法。该方法的线性范围为1.0×10^-2-7.0 mg/L,检出限为2.0×10^-3mg/L,相对标准偏差RSD（n=11,ρ=1.0 mg/L）为1.7%,回收率为94%-101%。已用于NaCl注射液中甲磺酸帕珠沙星的测定。