Flow-injection chemiluminescence determination of tryptophan using galangin-potassium permanganate-polyphosphoric acid system

A high sensitive flow-injection chemiluminescence （FI-CL） method for the determination of tryptophan has been developed. The method is based on the chemiluminescence reaction of galangin-potassium permanganate-tryptophan in polyphosphoric acid （PPA） media. Under the optimized conditions, tryptophan was determined in the range 0.05-10 μg/mL with the detection limit （3tr） of 5.0 × 10^-3 μg/mL. The relative standard deviation （RSD） was 1.0% for 11 replicate determinations of 1.0 μg/mL tryptophan. Three synthetic samples were determined selectively with recoveries in the range from 99.6% to 102.0% in the presence of other amino acids.

Flow-Injection Enhanced Chemiluminescence Method for Determination of Penicillamine

A new flow-injection procedure has been developed for the determination of penicillamine based on the enhancement of the chemiluminescence(CL) reaction of the penicillamine-cerium(Ⅳ)-hydrocortisone system. The method was simple, selective and sensitive with a detection limit of 6.2×10-5 mol·L-1(S/N=3). It was applicable to the determination of penicillamine in the concentration range of 2×10-6～5×10-4 mol·L-1. The method was successfully applied to the determination of penicillamine in tablets. The relative standard deviation (RSD) was 1.42% (n=7) and the recovery was 97%～103% (n=4).

Simultaneous Determination of Gold and Platinum by Double Artificial Neural Network Analysis with Flow-injection Chemiluminescence

A highly sensitive double artificial neural network （DANN） analysis with flow-injection chemiluminescence （FI-CL） has been developed to simultaneously determine the trace amounts of the gold and platinum in simulated mixed samples, without the boring process.

Flow-Injection Microcolumn on-Line Preconcentration for theDetermination of Chromium(Ⅵ)

A rapid and sensitive on-line preconcentration method for spectrophotometric determination of chromium (VI) in nature water is described. Preconcentration and determination are based on (i) the quantitative and fast adsorption of chromium (VI) on the high surface area nanometer-size TiO2 (anatase) powders, which prepared by a sol-gel method from hydrolysis of TiCI4 and (ii) the quantitative and reproducible elution of Cr (VI) by 2. 0 mol. L-1 HCI. A mini-column system for preconcentration is developed, Cr(VI)on the mini-column is eluted and merged with a stream water and DPCB (1, 5-diphenylcarbazide ) as the chromogenic reagent. The Proposed system permits throughputs of 6 sample h--l (0. 001 μg mL-1 Cr(VI) ) or 20 sample h-1 (0. 1 μg mL-1Cr (VI) . The preconcentration factor is 55. The detection limit is 0. 8 ng·mL-1 Cr(VI). The reproducibility is satisfactory with a relative standard deviation of less than 3. 35% (0. Of μg'mL-1Cr (VI), n = 5).

Flow-injection Chemiluminescence Determination of Trace Calf Thymus DNA

A flow injection procedure for the determination of calf thymus DMA （CT DNA） over the range 2.1x10-6;.1x10-1 B.g mL-1 is described, based on measurement of the enhanced chemiluminescence emission of rhodamine B-Ce（IV） system, activated by imidazole-HCl buffer solution. This method is highly sensitive, with the linearity range broadened to five orders of magnitude. It has been applied to determine CT DNA in synthetic sample with satisfactory results.

DETERMINATION OF TETRACYCLINE AND OXYTETRACYCLINE BY FLOW-INJECTION CHEMILUMINESCENCE METHOD

Objective To establish a rapid and precise continuous flow-injection chemiluminescence method for the determination of tetracycline and oxytetracycline. Methods In NaOH solution, tetracycline and oxytetracycline can sensitize obviously the chemiluminesence (CL) intensity of the reaction of luminol with KIO_4, the sensitized CL intensity is proportional to the concentration of tetracycline and oxytetracycline. So, a new flow-injection CL method has been developed. The optimum chemical conditions for the CL reaction were investigated. Results Under the optimized conditions (KIO_ 4 concentration: 1.0×10 -5 mol/L; NaOH concentration: 0.1 mol/L; luminol concentration: 1.0×10 -4mol/L), tetracycline and oxytetracycline were determined. The linear range of the working curves was 1.0×10 -7 - 1.0×10 -4g/mL, the detection limits was 1.0×10 -8g/mL and 1.1×10 -8g/mL, and the relative standard deviation was 2.6% (C_S=1.0×10 -6g/mL; n=11) and 2.0% (C_S=1.0×10 -6g/mL; n=11) respectively. Conclusion The method is simple, rapid, and sensitive, and it has been successfully applied to the the determination of tetracycline and oxytetracycline tablets, the mean recoveries being 99.7% and 98.8% respectively.

DETERMINATION OF ANTIMONY IN WATER SAMPLES BY FLOW-INJECTION HYDRIDE GENERATION ATOMIC ABSORPTION SPECTROMETRY WITH ON-LINE ION-EXCHANGE COLUMN PRECONCENTRATION

On-line ion-exchange separation and preconcentration were combined with flow-injection hydride generation atomic absorption spectrometry (HGAAS) to determine ultra-trace amounts of antimony in water samples. Antimony(Ⅲ) was preconcentrated on a micro-column packed with CPG-8Q chelating ion-exchanger using time-based sample loading and eluted by 4 mol l^(-1) HCl directly into the hydride generation AAS system. A detection limit (3σ) of 0.0015μg l^(-1) Sb(Ⅲ) was obtained on the basis of a 20 fold enrichment and with a sampling frequency of 60h^(-1). The precision was 1.0% r.s.d.(n=11) at the 0.5μg l^(-1) Sb(Ⅲ) level. Recoveries for the analysis of antimony in tap water, snow water and sea water samples were in the range 97-102%.

Flow-injection-enhanced chemiluminescence method for the determination of three β-blockers

Objective To develop a rapid,simple and sensitive chemiluminescence method for the determination of three β-blockers (bisoprolol,atenolol and propranolol). Methods The chemiluminescence of cerium (Ⅳ)-sulfite system was obviously sensitized by adding anyone of three β-blockers in acid media. A new chemiluminescence method was set up by combining with flow-injection technique and used to determine the three β-blockers. Results Good linear ranges were obtained at the concentrations of 2.0×10-7g/mL-4.0×10-5g/mL,1.0×10-7g/mL-3.0×10-5g/mL and 7.0×10-7g/mL-1.0×10-5g/mL,respectively,with the detection limits of 5.0×10-8g/mL,7.0×10-8g/mL and 5.0×10-8g/mL (S/N=3),respectively,and the relative standard deviations for 11 times consecutive injections of 1.0×10-6g/mL bisoprolol,atenolol and propranolol were 3.57%,2.21% and 2.26%,respectively. Conclusion The developed method is sensitive,accurate,rapid and of low cost. And it can be applied to determine bisoprolol,atenolol and propranolol in pharmaceutical preparations.

Electrogeneration of ferrate (Ⅵ) in low concentration NaOH solution for flow-injection-chemiluminescence detection

The possibility of direct analytical applications of ferrate（Ⅵ） solution,which was freshly electrogenerated in low-concentration NaOH electrolyte,was studied by a flow-injection-chemiluminescence（FI-CL） system.It was found that some inorganic ions, organic molecule and biomolecule could enhance the chemiluminescence emission caused by ferrate（Ⅵ）-luminol reaction.V（Ⅴ）, Ca（Ⅱ）,Mg（Ⅱ）,phloroglucinol,and bovine hemoglobin（Hb） chosen as samples were successfully detected by this developed method.The analytical characteristics of the system for the analytes determination including linear ranges,correlation coefficients, limits of detection combined with FI analysis were studied.

Flow-injection Chemiluminescence Determination of Catecholamines

A flow injection chemiluminescence (CL) method for the determination of catecholamines is described which is based on their inhibition of the intensity of CL from the luminol-hypochlorite system The hypochlorite was electrogenerated on-line by a constant current electrolysis, resulting in the elimination of the instability of the hypochlorite solution prepared from a commercial reagent of sodium hypochlorite. The detection limits are 0.6 ng/ml for dopamine, 0.8 ng/ml for adrenaline and isoprenaline. The proposed method has been successfully applied to the determination of catecholamines in pharmaceutical injections.

Flow-injection Chemiluminescence Sensor for the Determination of Gallic Acid by Immobilizing Luminol and Periodate on Anion-exchange Resin

A novel chemiluminescence (CL) sensor for the determination of gallic acid combined with flow injection analysis was developed by electrostatically immobilizing luminol and periodate on anion-exchange resins respectively. Gallic acid was sensed by its enhancing effect on the weak CL reaction between luminol and periodate, which were eluted from the ion exchange column. The possible reaction mechanism of the CL system was suggested and discussed. The response of the sensor to gallic acid concentration was linear over the range of 8.0×10 -9-1.0×10 -6 mol/L with a detection limit of 6.5×10 -9 mol/L (3σ). The relative standard deviation (RSD) for 7 repetitive determinations of gallic acid (1.0×10 -7 mol/L) was 1.8%. The sensor could be used for over 400 times determination with a good reproducibility.

Determination of thorium with DBF-arsenaz by flow-injection analysis

A sensitive,selective,rapid,simple,and convenient method for the determination of thorium was developed.The method was based on the color reaction of thorium with DBF-arsenazo in a strong acidic medium (4 mol/L HCI).The flow-injection technique was used with an automated flow- injection analyzer.Beer's law was obeyed in the range of 0—1.4 μg/mL.The relative standard deviations were less than 1%.

Chemiluminescence detection of permanganate index (COD_(Mn)) by a luminol-KMnO_4 based reaction

A novel chemiluminescence （CL） system for determination of permanganate index （CODMn） combined with flow injection analysis has been proposed in this study. On the basis of the chemiluminescent reaction of luminol-KMnO4 system, light emission caused by luminol-KMnO4 system was detected by the photomultiplier tube, and its intensity caused by the appearance of KMnO4 after sample digestion was inversely proportional to CODMn. Effects for CODMn determining such as pH, concentrations and interference were investigated in detail. A detection limit of 0.3 mg/L CODMn with a linear range of 0.3-200 mg/L for its theoretical CODMn was obtained under the optimized experimental conditions. The relative standard deviation was 4.3% for 5.0 mg/L CODMn （n = 11）. This CL flow system for determining CODMn was simple, rapid, and suitable for automatic analysis. The data obtained by the present method were fairly in good agreement with those obtained by the standard titrimetric method. It has been applied to determine real samples with satisfactory results.

Chemiluminescence Determination of Molybdenum by on-Line Reduction with a Flow Injection System

The chemiluminescence (CL) reaction between lucigenin (Lu) and molybdenum (III) produced by a Jones reductor was investigated using a flow injection system. On the basis of this, a novel method for the determination of trace amount of molybdenum has been established. The emission intensity was linear with molybdenum concentration in the range of 0.1-1000 ng/mL; the detection limit was 0.02 ng/mL molybdenum; the relative standard deviation was less than 2% for the determination of 0.1 ng/mL molybdenum (n=11). The method has been applied successfully to the analysis of trace molybdenum in water and steel samples.

Flow Injection Semi-online Preconcentration Graphite Furnace Atomic Absorption Spectrometry for Determination of Cadmium,Copper and Manganese

A micro-flow injection sorbent extraction preconcentration system was combined with a graphite furnace atomic absorption spectrometry that formed an integrated system for the determination of trace amounts of elements. The analytical performances of the prospsed method for determining Cd, Cu and Mn were studied. The analytes were preconcentrated with a thiol resin(Type 190, produced by Nankai University, China) whose active group is -SH. The elements to be determined were preconcentrated onto the column for 60 s and then rinsed with deionized water and eluted with 30 μL of 1 mol/L HCl. The graphite furnace atomic absorption spectrometry(GFAAS) determination of the concentrated analyte was carried out in parallel with the next preconcentration cycle. Enrichment factors 41, 22 and 20 and detection limits(3 σ , n =10) 0.36, 3.8 and 7.0 ng/L for Cd, Cu and Mn, respectively, along with a sampling frequency of 20 h -1 , were obtained with a 60 s loading time at a sample flow rate of 3.5 mL/min. The analytical results for a number of water samples show that the flow-injection semi-online column preconcentration can not only eliminate the effect of some concomitant elements, such as Li, Na, K, Ca and Mg, on the determination of the analyte, but also enhance the sensitivity.

Flow Injection Determination of Tramadol Based on Its Sensitizing Effect on the Chemiluminescent Reaction of Permanganate-Sulfite

In this paper, a novel chemiluminescence (CL) method for the determination of tramadol has been developed by combining the flow injection technique and its sensitizing effect on the weak CL reaction between sulfite and acidic KMnO4. A mechanism for the CL reaction has been proposed on the basis of fluorescent and CL spectra. Under the optimized conditions, the proposed method allows the measurement of tramadol hydrochloride over the range of 0.04 - 4 ?g/mLwith a correlation coefficient of 0.9995 (n = 8) and a detection limit of 0.01 ?g/mL (3σ), and the relative standard deviation for 2.0 ?g/mL tramadol (n = 11) is 2.1%. The utility of this method was demonstrated by determining tramadol hydrochloride in tablets and injections.

Simultaneous Biparametric Determination of Total Calcium and Potassium in Biological Fluids by Flow Injection Analysis──Use of Powell＇s Method in the System Optimization

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Determination of Biotin in Pharmaceutical Formulations by Potassium Permanganate-luminol-CdTe Nanoparticles Chemiluminescence System

A sensitive flow-injection chemiluminescence method was developed for the determination of biotin in the pharmaceutical formulations.The affinity between avidin and biotin was used to adsorb biotin on the polystyrene,with subsequent quantification of biotin based on its ability to enhance the chemiluminescence（CL） signal generated by the redox reaction of potassium permanganate-luminol-CdTe nanoparticles CL system.The investigations prove that apart from 3-aminophthalate,the CdTe quantum dots（QDs） play both catalytic and emitter roles.Under optimum conditions,the linear range for the determination of biotin was 0.01―25 ng/mL with a detection limit of 7.3×10-3 ng/mL（S/N=3）.The relative standard deviation of 5 ng/L biotin was 2.06%（n=7）.The proposed method was used to determine the biotin concentration in the pharmaceutical formulations and the recovery was between 96.4% and 104%.The proposed method is simple,convenient,rapid and sensitive.

Luminol-potassium permanganate chemiluminescence system for the determination of three anthracycline antibiotics

Objective To establish a flow-injection chemiluminescence method for the determination of doxorubicin,epirubicin and mitoxantrone and study its reaction mechanism.Methods In alkaline medium,chemiluminescence of luminol-potassium permanganate system could be inhibited obviously by anthracycline antibiotics.Combined with flow-injection technique,a new chemiluminescence method for determining the anthracycline antibiotics was set up.The chemiluminescence mechanism of the luminol-potassium permanganate system was also discussed.Results Under optimal conditions,the good linear ranges of doxorubicin,epirubicin and mitoxantrone were 5.0×10-9-1.0×10-6g/mL,1.0×10-9-1.0×10-5g/mL and 3×10-9-1.0×10-6g/mL,respectively.The detection limits of doxorubicin,epirubicin and mitoxantrone were 3.0×10-9g/mL,5.0×10-8g/mL and 2.0×10-9g/mL,respectively.During eleven repeated inter-day and intra-day precision tests of 1.0×10-6g/mL samples,the relative standard deviations corresponded to reference values of 3.0%,2.8% and 2.1%.Conclusion The developed method is sensitive,accurate,rapid and of low cost.It can be applied to determine doxorubicin hydrochloride,epirubicin hydrochloride and mitoxantrone hydrochloride in injection preparations.

Solid-Contact Perchlorate Sensor with Nanomolar Detection Limit Based on Cobalt Phthalocyanine Ionophores Covalently Attached to Polyacrylamide

Novel solid-contact perchlorate sensors based on cobalt phthalocyanine-C-monocarboxylic acid (I), and cobalt phthalocyanine-C,C,C,C-tetracarboxylic acid (II) as free ionophores and covalently attached to polyacryla- mide (PAA)—ionophores III and IV, respectively were prepared. The all solid-state sensors were constructed by the application of a thin film of a polymer cocktail containing a phthalocyanine ionophore and cetyltrimethylammonium bromide (CTMAB) as a lipophilic cationic additive onto a gold electrode precoated with the conducting polymer poly (3,4-ethylenedioxythiophene) (PEDOT) as an ion and electron transducer. The sensor with 10.3% of ionophore (III) covalently attached to plasticizer-free poly (butyl methacrylate-co-do- decyl methacrylate) (PBDA) exhibited a good selectivity for perchlorate and discriminated many ions, in- cluding F–, Cl–, Br–, I–, SCN–, , S2– and . The covalent attachment of the ionophore to the polymer resulted in a near-Nernstian anionic slope of –62.3 mV/decade whereas a super-Nernstian slope of –79.9 mV/ decade was obtained for the free ionophore. The sensor covered a linear concentration range of 5 × 10–9 - 1 × 10–2 mol?L–1 with a lower detection limit (LDL) of 1 × 10–9 mol?L–1 and gave a stable response over a pH range of 4 - 10.5. The all-solid state sensors were utilized for the selective flow injection potentiometric determination of perchlorate in natural water and human urine samples in the nanomolar concentration range.