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1.
《Analytical letters》2012,45(11-12):2445-2461
Abstract

A new chemiluminescence system reinforced by use of a surfactant and a metal catalyst is demonstrated for selective determination of adrenaline by a flow-injection method. The weak light emission originating from an aerobic oxidation of adrenaline in an alkaline solution is dramatically enhanced by ordered surfactant molecular assemblies, dioctadecyldimethylammonium chloride bilayer membrane vesicles, with the largest enhancement factor of 1000 which has not ever been realized. The enhanced emission is further increased by a Mn(II) catalyst with an enhancement factor of ca. 40. The limit of determination(S/N=2) is 1×10?8M (0.2 ng in 100-μ1 injection), the linear range is four ordrers of magnitude, the sample throughput is 100 h?1. and the relative standard deviation(n=5) is 0.9 % for 5×10?7M adrenaline. Of other substances including dopamine, noradrenaline, and related compounds, p-hydroxymandelenic acid chemiluminesces most strongly after adrenaline, the 1×10?3M solution providing a signal 24% of that for 1×10?6M adrenaline.  相似文献   

2.
A chemiluminescence sensor using a xanthene dye immobilized on an ion-exchange resin as an indicator phase is described for the continuous monitoring of free chlorine (HOCl) in tap water. Of the dyes and ion-exchange resins tested, the immobilization giving the best dynamic response characteristics was achieved with a combination of uranine and a weakly basic anion-exchange resin (Amberlite IRA-93). The sensor, a Pyrex tube (20 mm × 3 mm i.d.) packed with the resin and placed close to a photomultiplier tube, provided a constant signal within ca. 1 min of a concentration change of free chlorine, a linear calibration graph between 1 × 10?3 and 2 × 10?6 M (the detection limit at a signal-to-noise ratio of 3) and an r.s.d. of 1.6% for 1 × 10?5 M free chlorine. The sensor was unique in being insensitive to chloramines and permitted free chlorine to be determined in tap water with no interference from chloramines and other compounds.  相似文献   

3.
《Electroanalysis》2004,16(11):922-927
A novel chloride PVC‐based membrane sensor based on a ruthenium(III) Schiff's base complex, as an excellent neutral carrier, has been developed. The ruthenium complex, in combination with a ketonic plasticizer and a cationic additive led to ISEs with fundamental characteristics, such as slope sensitivity, short response times and selectivity coefficients, which were sufficient for practical applications. The sensor with composition of 30% PVC, 62% benzyl acetate, 5% ruthenium(III) Schiff's base complex and 3% hexadecyltrimethyl ammonium bromide displays near‐Nernstian behavior in a wide concentration range (1.0×10?1–3.0×10?6 M with slope of ?54.5±0.5) with a detection limit of 2.0×10?6 M (71.0 ng per mL). The response of the electrode is independent on pH in the range of 4.0–10.0 and can it be used for at least ten weeks. The proposed electrode shows a very short response time (<20 s) in whole concentration range. The sensor displays high selectivity toward chloride ions over several organic and inorganic anions. It was successfully applied for the determination of chloride in serum samples. It was also used as an indicator electrode in the potentiometric titration of chloride ions with silver nitrate solution.  相似文献   

4.
《Analytical letters》2012,45(4):595-606
A highly sensitive polyvinyl chloride (PVC) membrane electrode, based on copper(II)-bis(N-4-methylphenyl-salicyldenaminato) complex, (CuL2), as a carrier was reported for the determination of chromate ion. The influence of membrane composition, pH, and possible interfering anions on the response of the ion selective electrode was investigated. The sensor exhibited a Nernstian slope of 29.7 mV per decade when the chromate concentration was varied between 2.0 × 10?7–1.50 × 10?2 M in a wide pH range (6.0 to 9.0). The detection limit of the ion selective electrode was 9.2 × 10?8 M. The proposed sensor was used for at least 4 months without any considerable divergence in potential. It was applied as indicator electrode in potentiometric titration of chromate ion with Pb2+ and Tl+.  相似文献   

5.
《Electroanalysis》2004,16(21):1771-1776
In this work a dysprosium [Dy(III)]‐selective solvent polymeric membrane sensor based on N,N‐bis(pyrrolidene) benzne‐1,2‐diamine, poly(vinyl chloride)(PVC), the plasticizer benzylacetate (BA), and anionic site is described. This sensor responds to Dy(III) activity in a linear range from 1.0×10?5 to 1.0×10?1 M, with a slope of 20.6±0.2 mV per decade and a detection limit of 6.0×10?6 M at the pH range of 3.5–8.0. It has a fast response time of<20 s in the entire concentration range, and can be used for at least 2 months without any considerable divergence in the electrode potentials. The proposed sensor revealed comparatively good selectivity with respect to common alkali, alkaline earth, transition and heavy metal ions. It was used as an indicator electrode in the potentiometric titration of fluoride ions and in determination of concentration of F ions in some mouth washing solutions.  相似文献   

6.
《Analytical letters》2012,45(7):1041-1055
Abstract

A polyvinyl chloride (PVC) membrane sensor for ytterbium(III) ions was prepared, based on 2,5-bis(5-tert-butyl-benzoxazol-2-yl)thiophene (BBT) as a membrane carrier. The sensor illustrates the following characteristics: a linear dynamic range of 1.0 × 10?6 to 1.0 × 10?2 M; a Nernstian slope of 19.7 ± 0.5 mV decade?1; a detection limit of 4.4 × 10?7 M; a response time of <10 s; and use for at least 2 months without any significant potential divergence in the pH range of 3.5–8.4. Moreover, the recommended selective sensor revealed a comparatively satisfactory selectivity regarding most of the alkali and alkaline earth ions and some of the transition-metal and heavy-metal ions. In fact, it was used as an indicator electrode in the Yb(III) potentiometric titration with ethylene diamine tetra-acetic acid (EDTA) and the determination of concentration of Yb(III) ions in soil and sediment samples.  相似文献   

7.
《Analytical letters》2012,45(15):3271-3283
ABSTRACT

Six kinds of water-soluble porphyrin were examined as a sensitizer (fluorophore) in the bis(2,4,6-trichlorophenyl)oxalate(TCPO)-hydrogen peroxide (H2O2) chemiluminescence(CL) system. Among them, coproporphyrin III showed the highest CL intensity. Moreover, the TCPO-H2O2-coproporphyrin III CL system was separately examined in each micelle solution using a non-ionic surfactant such as Briji 35 and Triton X-100, and an ionic surfactant such as cetyltrimethylammonium chloride(CTAC) and sodium dodecylsulfate. As a result, the CL intensity along with the coexistence of the CTAC micelle increased approximately 36 times compared to that in the absence of surfactant. Based on these findings, the quenching CL determination of copper(II) was established using the complex formation of coproporphyrin III and copper(II) ion. The calibration graph for the concentration of copper(II) was linear in the range of 2×10?8M to 1×10?6M, and the detection limit(3σ) was 1.26×10?8M. Moreover, the relative standard deviation was 2.9%(10 determinations). The proposed method was applied to the determination of copper(II) ion in waste water and satisfactory results were obtained.  相似文献   

8.
《Electroanalysis》2005,17(10):895-900
A highly sensitive and selective membrane electrode with 9‐crown‐3 derivative (CD) as ionophore, potassium tetrakis‐(p‐chlorophenyl) borate as anionic additive (KTB), acetophenone (AP) as solvent mediator was prepared and investigated as a Be(II) sensor. The best performance was observed with the membrane having the percent ratio 30% PVC: 8% CD: 6% KTB: 56% Acetophenone. The poly(vinyl chloride) PVC membrane containing 9‐crown‐3 derivative (CD) directly coated on a graphite electrode, shows a Nernstian response for Be(II) ions over a very wide concentration range (1.0×10?1?1.0×10?7 M) with a detection limit of 8.0×10?8 M (ca. 0.72 ng/mL). It has a fast response time of ca. 20 s and can be used for at least 10 weeks without any major deviation in potential. The proposed sensor exhibits very good selectivity with respect to common alkali, alkaline earth, transition and heavy metal ions. The proposed sensor was used as end point indicator electrode in the titration of Be(II) ions with EDTA. It was also applied to determination of Be(II) in real sample.  相似文献   

9.
《Analytical letters》2012,45(16):2993-3001
Abstract

A novel optical sensor (optode) is described for the determination of thiocyanate using methyltrioctylammonium chloride immobilized on triacetylcellulose membrane. The response to thiocyanate is the result of adsorption of [Co(SCN)4]2? on sensing membrane, which caused the colorless membrane to change to blue. This optode can readily be regenerated by using 0.02 mol/l sodium oxalate solution. The linear range of the method was 3.44×10?5 to 8.61×10?4 mol/l of thiocyanate with a limit of detection 1.51×10?5 mol/l. The relative standard deviation for eight replicate measurements of 8.61×10?5 and 4.30×10?4 mol/l of thiocyanate was 3.45 and 1.23%, respectively. The sensor was successfully applied for the determination of thiocyanate in saliva of smokers, nonsmokers and various water samples.  相似文献   

10.
《Electroanalysis》2005,17(17):1534-1539
The construction, performance, and applications of a novel ytterbium(III) sensor based on N‐(2‐pyridyl)‐N′‐(2‐methoxyphenyl)‐thiourea (PMT), as an excellent carrier, in plasticized poly(vinyl chloride) PVC matrix, is described. The influences of membrane composition and pH on the potentiometric response of the sensor were investigated. The sensor exhibits a nice Nernstian response for Yb(III) ion over a wide concentration range of 4 decades of concentration (1.0×10?6–1.0×10?2 M), and a detection limit of 5.0×10?7 M. The response time of the electrodes is between 8 and 10 s, depending on the concentration of ytterbium(III) ions. The proposed sensor can be used for about 8 weeks without any considerable divergence in potential. The sensor revealed very good selectivity for Yb(III) in the presence of several metal ions. The best performance was observed for the membrane containing; 30% PVC, 59% o‐nitrophenyloctyl ether (NPOE) as solvent mediator, 7% PMT, and 4% sodium tetraphenyl borate (NaTPB). It was successfully applied as indicator electrodes in the potentiometric titration of Yb(III) with EDTA and for the determination of fluoride ion in two mouth wash formulations. The proposed La(III) sensor was found to work well under laboratory conditions. It was also used as an indicator electrode in titration of a 1.0×10?4 M of Yb(III) with a standard EDTA solution (1.0×10?2 M). It was also used for determination of Yb(III) ion in Xenotime .  相似文献   

11.
《Electroanalysis》2004,16(11):910-914
A novel bromide PVC‐based membrane sensor, based on iron(III)‐salen (IS) as an electroactive material, is successfully developed. The sensor possesses the advantages of low detection limit (6.0×10?6), wide working concentration range (7.0×10?6–1.0×10?1 M), Nernstian behavior (slope of 59.0±0.5 mV per decade), low response time (<15 s), wide working pH range (3–9), and specially, high bromide selectivity over a wide variety of organic and inorganic anions, specially iodide, chloride, and hydroxide ions. The electrode was used in the direct potentiometric determination of hyoscine butylbromide, and as an indicator electrode in potentiometric titration of bromide ions with silver ions.  相似文献   

12.
An amperometric enzyme electrode for the determination of hypoxanthine in fish meat is described. The hypoxanthine sensor was prepared from xanthine oxidase immobilized by covalent binding to cellulose triacetate and a carbon paste electrode containing hydroxymethylferrocene. The xanthine oxidase membrane was retained behind a dialysis membrane at a carbon paste electrode. The sensor showed a current response to hypoxanthine due to the bioelectrocatalytic oxidation of hypoxanthine, in which hydroxymethyiferrocene served as an electron-transfer mediator. The limit of detection is 6 × 10?7 M, the relative standard deviation is 2.8% (n=28) and the response is linear up to 7 × 10?4 M. The sensor responded rapidly to a low hypoxanthine concentration (7 × 10?4 M), the steady-state current response being achieved in less than 1 min, and was stable for more than 30 days at 5 ° C. Results for tuna samples showed good agreement with the value determined by the conventional method.  相似文献   

13.
Rifampicin can enhance the chemiluminescence (CL) of peroxomonosulfate‐cobalt(II) system, and the CL intensity is strongly dependent on the rifampicin concentrations. Based on this phenomenon, a rapid and sensitive flow injection CL method was developed for the determination of rifampicin. The relative CL intensity was linear with the rifampicin concentration over the range of 5×10?8 to 1×10?6 g·mL?1 (r=0.9991), the detection limit was 7×10?9 g·mL?1 (S/N=3), and the relative standard deviation was 2.7% for 6×10?7 g·mL?1 rifampicin (n=11). Furthermore, this method was successfully applied to the determination of rifampicin in real eye drop and capsules sample.  相似文献   

14.
《Electroanalysis》2004,16(16):1330-1335
A poly(vinyl chloride) membrane sensor based on oxalic acid bis (cyclohexylidene hydrazide) as membrane carrier was prepared and investigated as a Cr(III)‐selective electrode. The electrode reveals a Nernstian behavior (slope 19.8±0.4 mV decade?1) over a wide Cr(III) ion concentration range 1.0×10?7–1.0×10?2 mol dm?3 with a very low limit of detection (i.e., down to 6.3×10?8 mol dm?3). The potentiometric response of the sensor is independent of the pH of the test solution in the pH range 1.7–6.5. The electrode possesses advantage of very fast response, relatively long lifetime and especially good selectivity to wide variety of other cations. The sensor was used as an indicator electrode, in the potentiometric titration of chromium ion and in the determination of Cr(III) in waste water and alloy samples.  相似文献   

15.
A new procedure for constructing an optical fibre reflectance, bulk optode membrane type, sensor is presented. The optode membrane consists of a plasticized poly (vinyl chloride) membrane in which the ionophore is dissolved, entrapped in a cellulose support. The new optode with the dye indicator 1-(2-pyridylazo)-2-naphthol (PAN) was incorporated in a new flow-through cell and the injection system was optimized to determine Cu (II) at 567 nm in the range 5 × 10?5–10?3 M. The response was reproducible and the optode can be regenerated using 10?2 M EDTA followed by water. The method was applied to the determination of copper in real samples.  相似文献   

16.
《Analytical letters》2012,45(2):298-311
Abstract

A polyvinyl chloride (PVC) based membrane sensor for terbium ions was prepared by employing Hematoporphyrin (HP) as an ionophore. The sensor revealed a very good selectivity (expect for the Fe3+ion) with respect to common alkali, alkaline earth and heavy metal ions. The plasticized membrane electrode exhibits a Nernstian response for Tb3+ ions over a wide concentration range (1.0 × 10?6 ? 1.0 × 10?2 M) with a slope of 19.8±0.3 mV per decade and low detection limit of 7.4 × 10?7 M. The developed sensor was used in determination of F? in mouth wash preparation sample.  相似文献   

17.
《Analytical letters》2012,45(3):495-506
Abstract

A Dy(III) ion‐selective membrane sensor has been fabricated from polyvinyl chloride (PVC) matrix membrane containing a new asymmetrical Schiff's base [(E)‐N‐(2‐hydroxybenzylidene)benzohydraide] or BBH as a neutral carrier, sodium tetraphenyl borate (NaTPB) as an anionic excluder and nitrobenzene (NB) as a plasticizing solvent mediator. The membrane sensor displays linear potential response in the concentration range of 1.0×10?2–1.0×10?6 M of Dy(III). The electrode exhibits a nice Nernstian slope of 20.1±0.8 mV/decade in the pH range of 3.0–8.0. The sensor has a relatively short response time in whole concentration ranges (<20 s). The detection limit of the proposed sensor is 8.0×10?7 M (~128 ng/mL), and it can be used over a period of six weeks. The selectivity of the proposed sensor with respect to other cations, (alkali, alkaline earth, transition and heavy metal ions) and especially lanthanid ions, is excellent. The practical utility of the sensor has been demonstrated by using it as an indicator electrode in the potentiometric titration of Dy(III) with EDTA.  相似文献   

18.
张四纯  周国俊  鞠熀先 《中国化学》2002,20(10):1049-1054
IntroductionGallicacidexistsintheleavesandfruitsofmanytypesofplantsandiswidelyusedinmedicineforanti oxi dationandantibacterialactivity ,antiflammatoryactionandanti canceractivity .1 5Inspiteofthehealthimportanceofgallicacid ,itsmetabolismandkineticsinthehu…  相似文献   

19.
A detection system for hydrogen peroxide, i.e., luminol chemiluminescence (CL) in a hexadecyltrimethylammonium bromide (CTAB) reversed micellar system, was coupled to enzyme reactions. The use of CTAB reversed micellar medium allows one to conduct both the oxidase enzymatic and CL detection reactions simultaneously at mild pH (l-amino acid system, pH 8.7; glucose system, pH 8.5) in the absence of any co-oxidant or catalyst. Based on this result, simple and unique determinations of l-amino acids and glucose as substrates were developed. The calibration graph for a representative amino acid, l-phenylalanine, was linear in the concentration range 4.0×10?6?200×10?6M with a relative standard deviation of 5.78% (five determinations). The method established for l-phenylalanine was also applicable for the assay of fourteen other l-amino acids. The calibration graph for glucose was linear in the concentration range 5.4×10??540×10?6M with a relative standard deviation of 4.27% (eight determinations). This method was compared with a standard spectrophotometric method (hexokinase) and successfully applied to the determination of glucose in human serum.  相似文献   

20.
A samarium(III) selective potentiometric sensor has been prepared on the basis of polyvinyl chloride (PVC) membranes containing an ion exchanger (zirconium boratophosphate) as an electro-active material. The best performance was exhibited by a membrane having the following composition: zirconium boratophosphate (10%) and poly vinylchloride (90%). This membrane works well over a wide concentration range (from 1 × 10?5 to 1 ? 10?1 M) of Sm(III) ions with a Nernstian slope of 20.2 mV/decade. The response time of the sensor is 15 s, and the membrane can be used for more than six months with good reproducibility. Selectivity coefficients determined by the fixed interference method for a number of mono-, di-, and trivalent cations are reported. The sensor has also been used as an indicator electrode in the potentiometric titrations of samarium (III) ions with EDTA solution.  相似文献   

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