Time measurement-visual analysis of nickel(II) using autocatalytic reaction with sodium sulfite/hydrogen peroxide system and its application to the length detection-flow analysis

Trace amounts of nickel(II) can function as a trigger (=reaction initiator) in an autocatalytic reaction with the sodium sulfite/hydrogen peroxide system. Based on this finding, sub-μg L⁻¹ levels of nickel(II) were determined by a time measurement using the autocatalytic reaction. The detection range using the above method was 10⁻⁹–10⁻⁵ M, the detection limit (3σ) was 8.1 × 10⁻¹⁰ M (0.047 μg L⁻¹), and the relative standard deviation was 2.66% at nickel(II) concentration of 10⁻⁷ M (n = 7). This method was applied to length detection-flow injection analysis. The detection range for the flow injection analysis was 2 × 10⁻⁹–2 × 10⁻³ M. The detection limit (3σ) was 1.4 × 10⁻⁹ M (0.082 μg L⁻¹), and the relative standard deviation was 1.86 at initial nickel(II) concentration of 10⁻⁶ M (n = 7).     

Sensitive determination of phenylephrine and chlorprothixene at poly(4-aminobenzene sulfonic acid) modified glassy carbon electrode

Phenylephrine (i.e. PHE) and chlorprothixene (i.e. CPT), two effective and important antipsychotic drugs with low redox activity, were found generating an irreversible anodic peak at about +0.89 V (vs. SCE) and +1.04 V in 0.05 M HAc–NaAc (pH 5.0) or NH₂CH₂COOH–HCl (pH 2.4) buffer solution at poly(4-aminobenzene sulfonic acid) modified glassy carbon electrode (i.e. poly(4-ABSA)/GC), respectively. Sensitive and quantitative measurement for them based on the anodic peaks was established under the optimum conditions. The anodic peak current was linear to PHE and CPT concentrations from 1 × 10⁻⁷ to 1.5 × 10⁻⁵ M and 2 × 10⁻⁶ to 4.5 × 10⁻⁵ M, the detection limits obtained were 1 × 10⁻⁸ and 1 × 10⁻⁷ M, separately. The modified electrode exhibited some excellent characteristics including easy regeneration, high stability, good reproducibility and selectivity. The method proposed was successfully applied to the determination of PHE and CPT in drug injections or tablets and proved to be reliable compared with ultraviolet spectrophotometry. The modified electrode was characterized by electrochemical methods.     

Square wave adsorptive stripping voltammetric determination of famotidine in urine

Electrochemical studies of famotidine were carried out using voltammetric techniques: cyclic voltammetry, linear sweep and square wave adsorptive stripping voltammetry. The dependence of the current on pH, buffer concentration, nature of the buffer, and scan rate was investigated. The best results for the determination of famotidine were obtained in MOPS buffer solution at pH 6.7. This electroanalytical procedure enabled to determine famotidine in the concentration range 1 × 10⁻⁹–4 × 10⁻⁸ mol L⁻¹ by linear sweep adsorptive stripping voltammetry (LS AdSV) and 5 × 10⁻¹⁰–6 × 10⁻⁸ mol L⁻¹ by square wave adsorptive stripping voltammetry (SW AdSV). Repeatability, precision and accuracy of the developed methods were checked. The detection and quantification limits were found to be 1.8 × 10⁻¹⁰ and 6.2 × 10⁻¹⁰ mol L⁻¹ for LS AdSV and 4.9 × 10⁻¹¹ and 1.6 × 10⁻¹⁰ mol L⁻¹ for SW AdSV, respectively. The method was applied for the determination of famotidine in urine.     

Enzymatic biosensor for the electrochemical detection of 2,4-dinitrotoluene biodegradation derivatives

In this work, we demonstrate for the first time that 4-methyl-5-nitrocatechol (4M5NC) and 2,4,5-trihydroxytoluene (2,4,5-THT), two compounds obtained from the 2,4-DNT biodegradation are recognized by polyphenol oxidase as substrates. An amperometric biosensor is described for detecting these compounds and for evaluating the efficiency of the 2,4-DNT conversion into 4M5NC in the presence of bacteria able to produce the 2,4-DNT-biotransformation. The biosensor format involves the immobilization of polyphenol oxidase into a composite matrix made of glassy carbon microspheres and mineral oil. The biosensor demonstrated to be highly sensitive for the quantification of 4M5NC and 2,4,5-THT. The analytical parameters for 4M5NC are the following: sensitivity of (7.5 ± 0.1) × 10⁵ nAM⁻¹, linear range between 1.0 × 10⁻⁵ and 8.4 × 10⁻⁵ M, and detection limit of 4.7 × 10⁻⁶ M. The sensitivity for the determination of 2,4,5-THT is (6.2 ± 0.6) × 10⁶ nAM⁻¹, with a linear range between 1.0 × 10⁻⁶ and 5.8 × 10⁻⁶ M, and a detection limit of 2.0 × 10⁻⁷. Under the experimental conditions, it was possible to selectively quantify 4M5NC even in the presence of a large excess of 2,4-DNT. The suitability of the biosensor for detecting the efficiency of 2,4-DNT biotransformation into 4M5NC is demonstrated and compared with HPLC-spectrophotometric detection, with very good correlation. This biosensor holds great promise for decentralized environmental testing of 2,4-DNT.     

Determination of fenoterol and salbutamol in pharmaceutical formulations by electrogenerated chemiluminescence

Fenoterol and salbutamol were determined by electrogenerated chemiluminescence (ECL) coupled with flow injection analysis (FIA), using Ru(bpy)₃²⁺ as the luminescent substance. Fenoterol and salbutamol oxidize together with the ruthenium 2,2-bipyridyl at a platinum electrode, which leads to an increase in the luminescent intensity, and this increase is proportional to the analyte concentration. For fenoterol a linear calibration curve within the range from 1.0 × 10⁻⁵ to 1.0 × 10⁻⁴ mol l⁻¹ was obtained with a correlation coefficient of 0.998 (n = 5) and for salbutamol the linear analytical curve was also obtained in this range with a correlation coefficient of 0.995 (n = 5). The relative standard deviation was estimated as ≤2.5% for 3 × 10⁻⁵ mol l⁻¹ for fenoterol solution and as ≤1.3% for 5.0 × 10⁻⁵ mol l⁻¹ salbutamol solution for 15 successive injections. The limit of detection for fenoterol was 2.4 × 10⁻⁷ mol l⁻¹ and for salbutamol was 4.0 × 10⁻⁷ mol l⁻¹. Fenoterol and salbutamol were successfully determined in drug tablets and the soluble components of the matrix did not interfere in the luminescent emission. The results obtained using the luminescent methodology were not statistically different from those obtained by UV-spectrophotometry at 95% confidence level.     

Highly selective and sensitive copper(II) membrane coated graphite electrode based on a recently synthesized Schiff’s base

A PVC membrane electrode based on bis-2-thiophenal propanediamine (TPDA) coated directly on graphite is described. The electrode exhibits a Nernstian response for Cu²⁺ over a very wide concentration range (1.0×10⁻¹ to 6.0×10⁻⁸ M) with a detection limit of 3.0×10⁻⁸ M (2.56 ng ml⁻¹). It has a fast response time and can be used for at least 2 months without any major deviation. The proposed sensor revealed very good selectivities for Cu²⁺ over a wide variety of other metal ions and could be used in the pH range of 3.0–7.0. It was successfully used for direct determination of copper in black tea and as an indicator electrode in potentiometric titration of copper ion.     

An NMR study of methanol diffusion in polymer electrolyte fuel cell membranes

Methanol diffusion in two polymer electrolyte membranes, Nafion 117 and BPSH 40 (a 40% disulfonated wholly aromatic polyarylene ether sulfone), was measured using a modified pulsed field gradient NMR method. This method allowed for the diffusion coefficient of methanol within the membrane to be determined while immersed in a methanol solution of known concentration. A second set of gradient pulses suppressed the signal from the solvent in solution, thus allowing the methanol within the membrane to be monitored unambiguously. Over a methanol concentration range of 0.5–8 M, methanol diffusion coefficients in Nafion 117 were found to increase from 2.9 × 10⁻⁶ to 4.0 × 10⁻⁶ cm² s⁻¹. For BPSH 40, the diffusion coefficient dropped significantly over the same concentration range, from 7.7 × 10⁻⁶ to 2.5 × 10⁻⁶cm² s⁻¹. The difference in diffusion behavior is largely related to the amount of solvent sorbed by the membranes. Increasing the methanol concentration results in an increase in solvent uptake for Nafion 117, while BPSH 40 actually excludes the solvent at higher concentrations. In contrast, diffusion of methanol measured via permeability measurements (assuming a partition coefficient of 1) was lower (1.3 × 10⁻⁶ and 6.4 × 10⁻⁷ cm² s⁻¹ for Nafion 117 and BPSH 40 respectively) and showed no concentration dependence. The differences observed between the two techniques are related to the length scale over which diffusion is monitored and the partition coefficient, or solubility, of methanol in the membranes as a function of concentration. For the permeability measurements, this length is equal to the thickness of the membrane (178 and 132 μm for Nafion 117 and BPSH 40 respectively) whereas the NMR method observes diffusion over a length of approximately 4–8 μm. Regardless of the measurement technique, BPSH 40 is a greater barrier to methanol permeability at high methanol concentrations.     

Determination of fenfluramine based on potassium permanganate-calcein chemiluminescence system

Calcein was found to be able to use as chemiluminescence reagent and post-chemiluminescence was observed when fenfluramine was injected into the mixture after the CL reaction of calcein–potassium permanganate. Based on this phenomenon, a flow injection CL method was established for the determination of fenfluramine. The possible CL mechanism was proposed. The CL intensity was correlated linearly with the concentration of fenfluramine over the range of 1.0 × 10⁻⁷ to 6.0 × 10⁻⁶ g mL⁻¹ and the detection limit was 6 × 10⁻⁸ g mL⁻¹. The relative standard deviation was 2.2% for 5.0 × 10⁻⁷ g mL⁻¹ fenfluramine (n = 11). This method was applied to the determination of fenfluramine in weight-reducing tonic successfully.     

Iodide-selective carbon paste electrodes based on recently synthesized Schiff base complexes of Fe(III)

A new modified carbon paste electrode (CPE) based on a recently synthesized Schiff base complex of Fe(III) as a suitable carrier for I⁻ ion is described. The electrode exhibits a super Nernstian slope of 71.0±0.3 mV per decade for I⁻ ion over a wide concentration range from 1.0×10⁻⁶ to 5.0×10⁻¹ M, with a low detection limit of 6.5×10⁻⁷ M. It has a relatively fast response time, a satisfactory reproducibility and relatively long life time. The proposed sensor shows a fairly good selectivity toward I⁻ ion in comparison to other common anions. The potentiometric response is independent of the pH of the test solution in the pH range 3.5–10.0. Spectrophotometric studies confirmed the redox-type response mechanism of the electrode toward iodide ion. The proposed electrode was used as an indicator electrode in potentiometric titration of iodide ion.     

Threonine-FX dosimeter for food irradiation

A detailed study for the spectrophotometric readout method for L-threonine powder, [CH₃CH(OH)CH(NH₂)COOH], was done. In this method, 400 mg unirradiated/irradiated L-threonine powder was dissolved in 10 ml of a solution which contains 3×10⁻⁴ mol dm⁻³ ferrous ammonium sulphate and 1.7×10⁻⁴ mol dm⁻³ xylenol orange (XO) in aerated aqueous 0.17 mol dm⁻³ sulphuric acid (FX). The peroxy radicals produced from irradiated threonine oxidize ferrous ions and XO forms a complex with ferric ions as well as controls the chain length of ferrous ion oxidation. The plot of absorbance at 556 nm against dose is linear in the dose range 20–400 Gy and doses down to about 1 Gy can be measured using 10-cm path cells. Response of the dosimeter is independent of irradiation temperature above 20. A dose of 50 Gy–10 kGy can be measured dissolving 50 mg threonine powder in 10 ml of a solution which contains 3×10⁻⁴ mol dm⁻³ ferrous ammonium sulphate and 1.3×10⁻⁴ mol dm⁻³ XO in aerated aqueous 0.06 mol dm⁻³ sulphuric acid (FX). The plot of absorbance at 552 nm against dose is non-linear. However dosimeter shows linear dose response up to 1000 Gy. Irradiated threonine powder is stable for about 3 months. The reproducibility of the method is better than ±2%. This dosimeter is very useful as transfer dosimeter for food irradiation programme.     

Molecularly imprinted polymer-based potentiometric sensor for degradation product of chemical warfare agents: Part I. Methylphosphonic acid

A biomimetic potentiometric sensor for the specific recognition of methylphosphonic acid (MPA), the degradation product of nerve agents sarin, soman, VX, etc., was designed. This involves the preparation of MPA imprinted polymer particles and removal of the template by soxhlet extraction. Subsequently, the leached MIP particles were dispersed in 2-nitrophenyloctyl ether (plasticizer) and embedded in polyvinyl chloride matrix. The sensor responds to MPA in the concentration range 5 × 10⁻⁸ to 1 × 10⁻⁴ and 1 × 10⁻³ to 1 × 10⁻¹ M with a detection limit of 5 × 10⁻⁸ M. The selectivity of the sensor has been tested with respect to chemical analogues such as phosphoric acid, sodium dihydrogen phosphate, organophosphorous pesticide and triazine herbicides. The utility of the sensor was tested for field monitoring of MPA in spiked ground water.     

Zn(II)-selective membrane electrode based on tetra(2-aminophenyl) porphyrin

A new PVC membrane electrode for Zn²⁺ ions based on tetra(2-aminophenyl) porphyrin (TAPP) as membrane carrier is prepared. The sensor exhibits a linear stable response over a wide concentration range (5.0×10⁻⁵ to 1.0×10⁻¹ M) with a slope of 26.5 mV/decade and a limit of detection 3.0×10⁻⁵ M (1.96 ppm). It has a response time of about l0 s and can be used for at least 8 months without any divergence in potential. The propose membrane sensor revealed good selectivities for Zn²⁺ over a wide variety of other metal ions and can be used in pH range of 3.0–6.0. It was successfully applied to the direct determination of zinc in a pharmaceutical sample and also as an indicator electrode in potentiometric titration of Zn²⁺ ions.     

Voltammetric determination of glucose based on reduction of copper(II)–glucose complex at lanthanum hydroxide nanowire modified carbon paste electrodes

A novel voltammetric method for the determination of β-d-glucose (GO) is proposed based on the reduction of Cu(II) ion in Cu(II)(NH₃)₄²⁺–GO complex at lanthanum(III) hydroxide nanowires (LNWs) modified carbon paste electrode (LNWs/CPE). In 0.1 mol L⁻¹ NH₃·H₂O–NH₄Cl (pH 9.8) buffer containing 5.0 × 10⁻⁵ mol L⁻¹ Cu(II) ion, the sensitive reduction peak of Cu(II)(NH₃)₄²⁺–GO complex was observed at −0.17 V (versus, SCE), which was mainly ascribed to both the increase of efficient electrode surface and the selective coordination of La(III) in LNW to GO. The increment of peak current obtained by deducting the reduction peak current of the Cu(II) ion from that of the Cu(II)(NH₃)₄²⁺–GO complex was rectilinear with GO concentration in the range of 8.0 × 10⁻⁷ to 2.0 × 10⁻⁵ mol L⁻¹, with a detection limit of 3.5 × 10⁻⁷ mol L⁻¹. A 500-fold of sucrose and amylam, 100-fold of ascorbic acid, 120-fold of uric acid as well as gluconic acid did not interfere with 1.0 × 10⁻⁵ mol L⁻¹ GO determination.     

Kinetic method for the determination of traces of thyroxine by its catalytic effect on the Mn(III) metaphosphate-As(III) reaction

A new, highly sensitive and simple kinetic method for the determination of thyroxine was proposed. The method was based on the catalytic effect of thyroxine on the oxidation of As(III) by Mn(III) metaphosphate. The kinetics of the reaction was studied in the presence of orthophosphoric acid. The reaction rate was followed spectrophotometrically at 516 nm. It was established that orthophosphoric acid increased the reaction rate and that the extent of the non-catalytic reaction was extremely small. A kinetic equation was postulated and the apparent rate constant was calculated. The dependence of the reaction rate on temperature was investigated and the energy of activation and other kinetic parameters were determined.

Thyroxine was determined under the optimal experimental conditions in the range 7.0 × 10⁻⁹ to 3.0 × 10⁻⁸ mol L⁻¹ with a relative standard deviation up to 6.7% and a detection limit of 2.7 × 10⁻⁹ mol L⁻¹. In the presence of 0.08 mol L⁻¹ chloride, the detection limit decreased to 6.6 × 10⁻¹⁰ mol L⁻¹. The proposed method was applied for the determination of thyroxine in tablets. The accuracy of the method was evaluated by comparison with the HPLC method.     

Application of lead film electrode for simultaneous adsorptive stripping voltammetric determination of Ni(II) and Co(II) as their nioxime complexes

An adsorptive stripping voltammetric (AdSV) procedure for simultaneous determination of Ni(II) and Co(II) in the presence of nioxime as a complexing agent at an in situ plated lead film electrode was described. The Co(II) signal was enhanced by exploitation of the catalytic process in the presence of nitrite. Ni(II) and Co(II) signals are better separated than in the case of bismuth film electrodes. Calibration graphs for an accumulation time of 120 s are linear from 1 × 10⁻⁹ to 1 × 10⁻⁷ mol L⁻¹ and from 1 × 10⁻¹⁰ to 5 × 10⁻⁹ mol L⁻¹ for Ni(II) and Co(II), respectively. The proposed procedure was applied for Ni(II) and Co(II) determination in water certified reference materials.     

Enhancement effect of sodium dodecyl benzene sulfonate (SDBS) and its application into voltammetric determination of telmisartan

A sensitive and rapid electrochemical method was developed for the determination of telmisartan based on the enhancement effect of sodium dodecyl benzene sulfonate (SDBS). In 0.1 mol L⁻¹ HClO₄ and in the presence of 7.5 × 10⁻⁵ mol L⁻¹ SDBS, a well-defined and sensitive oxidation peak was observed for telmisartan at the acetylene black (AB) paste electrode. However, the oxidation peak is poor-shaped and the peak current is very low in the absence of SDBS, suggesting that SDBS shows obvious enhancement effect for the determination of telmisartan. After all the experimental parameters were optimized, a sensitive and simple electrochemical method was developed for determining telmisartan. The oxidation peak current is proportional to the concentration of telmisartan over the range from 2.5 × 10⁻⁷ to 2.0 × 10⁻⁵ mol L⁻¹. The detection limit is 7.5 × 10⁻⁸ mol L⁻¹ after 2 min of accumulation. This new voltammetric method was successfully used to detect telmisartan in drugs.     

A fluorescent chemosensor for cobalt ions based on a multi-substituted phenol-ruthenium(II) tris(bipyridine) complex

An amide-linked 2,6-bis{[(2-hydroxy-5-tert-butylbenzyl)(pyridyl-2-methyl)-amino]-methyl}-4-methylphenol-ruthenium(II) tris(bipyridine) 2PF₆⁻ complex, 1, was first used to recognize Co(II) in EtOH/H₂O (1:1, v/v) solution, with the ruthenium(II) tris(bipyridine) moiety selected as a fluorophore and the multi-substituted phenol unit chosen as a receptor. The fluorescence quenching of 1 was attributed to the formation of an inclusion complex between multi-substituted phenol unit and Co(II) by 1:1 complex ratio (K = 2.5 × 10⁵), which has been utilized as the basis of the fabrication of the Co(II)-sensitive fluorescent chemosensor. The analytical performance characteristics of the proposed Co(II)-sensitive chemosensor were investigated. The sensor can be applied to the quantification of Co(II) with a linear range covering from 1.0 × 10⁻⁷ to 5.0 × 10⁻⁵ M and a detection limit of 5 × 10⁻⁸ M. The experiment results show that the response behavior of 1 to Co(II) is pH-independent in medium condition (pH 4.5–9.5) and show excellent selectivity for Co(II) over transition metal cations except Cu(II). The chemosensor has been used for determination of Co(II) in water samples.     

Flow-injection chemiluminescence determination of tetracyclines with in situ electrogenerated bromine as the oxidant

By designing a novel flow-through electrolytic cell (FEC), bromine was produced near to the surface of the platinum electrode by electrochemical oxidation of acidic KBr. The fast and weak chemiluminescence signal produced by the chemical reaction of the electrogenerated bromine with H₂O₂ was greatly enhanced by tetracyclines Based on these observations, a new, sensitive and simple electrogenerated chemiluminescence (ECL) method for the determination of tetracyclines was developed. Under the optimum experimental conditions, the calibration graphs are linear over the range 3.0×10⁻⁸ to 5.0×10⁻⁵ g ml⁻¹ for tetracycline, 2.0×10⁻⁷ to 2.4×10⁻⁵ g ml⁻¹ for oxytetracycline and 1.0×10⁻⁷ to 5.0×10⁻⁵ g ml⁻¹ for chlortetracycline. The limits of detection (S/N=3) are 1.0×10⁻⁸ g ml⁻¹ for tetracycline, 7.0×10⁻⁸ g ml⁻¹ for oxytetracycline and 1.5×10⁻⁷ g ml⁻¹ for chlortetracycline. For the determination 5.0×10⁻⁷ g ml⁻¹ tetracycline, the relative standard deviation was <5%. The proposed method was used to determine tetracyclines in pharmaceutical formulations.     

Effect of monascus pigment derivatives on the electrophoretic mobility of bacteria, and the cell adsorption and antibacterial activities of pigments

Various amino acid derivatives of monascus pigments were synthesized. The effects of pigment derivatives on the pigment adsorption ratio, electrophoretic mobility (EPM) of bacterial cells, and antibacterial activity were investigated under varying conditions of pigment type, pigment concentration, pH, and ionic strength. Two hydrophobic and two hydrophilic derivatives were selected as model pigments. There was a close relationship between the antimicrobial activity and the pigment adsorption ratio. Against Escherichia coli, the hydrophobic l-Tyr and l-Phe derivatives (log P = 3.18 and 3.57) exhibited high antimicrobial activities (MIC = 8 and 16 mg/L) and high cellular adsorption ratios (9.6 and 10.9 mg/L). The hydrophilic l-Glu and l-Asn derivatives (log P = 1.40 and 0.47) exhibited low activities (MIC = 64 and 128 mg/L) and low adsorption ratios (4.7 and 4.0 mg/L). The electrophoretic mobility of 11 different bacteria varied between −1.93 × 10⁻⁸ and −1.19 × 10⁻⁸ m² V⁻¹ s⁻¹ regardless of Gram⁺ or Gram⁻. The l-Phe derivative showed low MIC values (high antimicrobial activities) against bacteria with a high electrophoretic mobility. A positive linearity between the pigment adsorption ratio and the electrophoretic mobility was established. When the four pigment derivatives were added to E. coli solutions, the electrophoretic mobility of cells in all cases sharply increased with an increasing pigment concentration. The mobility value was high for hydrophobic pigment derivatives in descending order of l-Phe (0.8 × 10⁻⁸ m² V⁻¹ s⁻¹), l-Tyr (0.68 × 10⁻⁸ m² V⁻¹ s⁻¹), l-Glu (0.46 × 10⁻⁸ m² V⁻¹ s⁻¹), and l-Asn (0.44 × 10⁻⁸ m² V⁻¹ s⁻¹). Additional adsorption of the hydrophobic derivatives probably occurred due to a hydrophobic interaction between the pigment and the pigment-coated cells. The electrophoretic mobility decreased gradually with an increasing pH and/or ionic strength with both addition and no addition of the pigment derivatives. The pattern of change of the pigment adsorption ratio under varying pH and/or ionic strength values was similar to the pattern for electrophoretic mobility.     

Determination of chromium(III) and total chromium using dual channels on glass chip with chemiluminescence detection

A simple, rapid and sensitive method for the determination of chromium(III) and total chromium using the simple dual T channels on glass chip with negative pressure pumping system and chemiluminescence (CL) detection is presented. The CL reaction was based on luminol oxidation by hydrogen peroxide in basic aqueous solution catalyzed by chromium(III). Total chromium in form of chromium(III) was achieved after chromium(VI) was completely reduced by acidic sodium hydrogen sulfite. Total chromium could then be determined with the same strategy as the chromium(III). The CL reagent was composed of 1.0 × 10⁻⁴ mol/L luminol, 1.0 × 10⁻² mol/L hydrogen peroxide and 0.10 mol/L sodium bromide in 0.050 mol/L carbonate buffer (pH 11.00). The 1.0 × 10⁻² mol/L ethylenediaminetetraacetic acid was added into the sample solution in order to improve the selectivity. Chromium(III) could be detected at a notably concentration of 1.6 × 10⁻¹⁶ mol/L and a linear calibration curve was obtained from 1.0 × 10⁻¹⁵ to 1.0 × 10⁻¹³ mol/L. The sample and CL reagent consumption were only 15 and 20 μL, respectively. The analysis time was less than 1 min per sample with the precision (%R.S.D.) was 4.7%. The proposed method has been applied successfully to the analysis of river water, mineral waters, drinking waters and tap water. Its performance was verified by the analysis of certified total chromium-reference materials and by recovery measurement on spiked synthetic seawater sample.