Recommendations for nomenclature of ionselective electrodes (IUPAC Recommendations 1994)

As características, o desempenho e a aplicação de um eletrodo do tipo Pt⎪Hg⎪Hg 2 (NAP) 2 ⎪ Graphite, onde NAP=íon naproxenato, são descritas. O eletrodo responde a NAP com sensibilidade de (58,1± 0,9) mV década -1 no intervalo de 5,0 × 10 -5 -1,0 × 10 -2 mol L -1 , a pH 6,0-9,0 e com um limite de detecção de 3,9 × 10 -5 mol L -1 . O eletrodo é de baixo custo e facilmente construído, apresenta um rápido tempo de resposta (10-35 s) e pode ser usado por um período de seis meses sem qualquer divergência considerável nos potenciais. O sensor supracitado mostrou boa seletividade para naproxeno na presença de várias substâncias, tais como carboxilatos e ânions inorgânicos, sendo aplicado na análise direta de naproxeno em medicamentos (comprimidos) via método da adição de padrão. Os resultados analíticos obtidos com o eletrodo proposto estão em boa concordância com aqueles obtidos pelo procedimento preconizado na Farmacopéia Americana.The characteristics, performance, and application of an electrode, namely, Pt⎪Hg⎪Hg 2 (NAP) 2 ⎪ Graphite, where NAP stands for naproxenate ion, are described. This electrode responds to NAP with sensivity of (58.1± 0.9) mV decade -1 over the range 5.0 × 10 -5 -1.0 × 10 -2 mol L -1 at pH 6.0-9.0 and a detection limit of 3.9 × 10 -5 mol L -1 . The electrode is easily constructed at a relatively low cost with fast response time (within 10-35 s) and can be used for a period of 6 months without any considerable divergence in potentials. The proposed sensor displayed good selectivity for naproxen in the presence of several substances, especially concerning carboxylate and inorganic anions. It was used for the direct assay of naproxen in commercial tablets by means of the standard additions method. The analytical results obtained by using this electrode are in good agreement with those given by the United States Pharmacopeia procedure.Keywords: naproxenate-sensitive electrode, potentiometry, pharmaceutical formulations Introduction Naproxen [(+)-2-(6-metoxy-2naphthyl)propionic acid], is a non-steroidal anti-inflammatory drug that also presents analgesic and antipyretic properties often preferred to acetylsalicylic acid because of its better absortion following oral administration and fewer adverse effects.Naproxen is extensively used in the treatment of many diseases like rheumatoid arthrits, degenerative joint disease, ankylosing spondylits, acute gout and primary dismenorrea. 1 Like other non-steroidal anti-inflammatory drugs, it inhibits the biosyntesis of prostaglandins. 1 The United States Pharmacopeia 2 2003 reports an highperformance liquid chromatography (HPLC) method for the determination of naproxen tablets. Several analytical methods have been reported for the determination of naproxen in pharmaceutical preparations including UV-visible spectrophotomery, 3-5 spectrofluorimetry, 6-8 room temperature phosphorimetry, 9,10 voltametry, 11 high-performance liquid chromatography, 12-14 capillary electrophoresis, 15,16 coulometry 17 and oscilometric titration. 18 However, most of these techniq...

Section: Resultsmentioning

confidence: 99%

Section: Electrode Responsementioning

confidence: 99%

A novel potentiometric naproxenate ion sensor immobilized in a graphite matrix for determination of naproxen in pharmaceuticals

Santini¹,

Oliveira²,

Pezza³

et al. 2006

“…53 The response time of the electrode was tested by measuring the time required to achieve a steady state potential (within ± 0.2 mV min -1 ), for 1.0 × 10 -2 to 1.0 × 10 -6 mol L -1 NaFur solutions at pH 8.5. 53 The electrode yielded steady potentials within 10 to 15 s at high concentrations (≥ 1.0 × 10 -3 mol L -1 ) and about 20 s at concentrations near the detection limit. The experimental results show that the lifetime of the electrode was about 6 months, with a total of 620 determinations.…”

Section: Response Time and Lifetime Of The Electrodementioning

confidence: 99%

“…The detection limit, as determined from the intersection of the two extrapolated segments of the calibration graph (Figure 1), was 3.8 × 10 -7 mol L -1 . 53 The sensor response displayed good stability and repeatability over the tests; the last mentioned feature is illustrated by the standard deviation values shown in Table 2.For the reasons previously mentioned the Fur-sensitive electrode with composition of 50% (graphite, m/m) was chosen to perform all of the following studies. …”

mentioning

confidence: 97%

Potentiometric sensor for furosemide determination in pharmaceuticals, urine, blood serum and bovine milk

Santini¹,

Pezza²,

Sequinel³

et al. 2009

A construção, avaliação e aplicação analítica de um sensor potenciométrico do tipo PtHgHg 2 (Fur) 2 Grafite, onde Fur significa íon 4-cloro-N-furfuril-5-sulfamoil-antranilato, são descritas. O eletrodo responde a Fur com sensibilidade de (−58,4 ± 0,9) mV década -1 no intervalo de 5,0 × 10 -7 -1,0 × 10 -2 mol L -1 , a pH 7,0-9,0 e com um limite de detecção de 3,8 × 10 -7 mol L -1 . O eletrodo é facilmente construído e de baixo custo, apresenta um rápido tempo de resposta (10-20 s) e pode ser usado por um período de 6 meses sem qualquer variação considerável nas suas características de desempenho. O eletrodo proposto mostrou boa seletividade na presença de várias substâncias, bem como na presença de alguns carboxilatos e ânions inorgânicos. O eletrodo foi aplicado com sucesso na determinação de furosemida em medicamentos, urina, soro sanguíneo e amostras comerciais de leite bovino.The construction, evaluation and analytical application of a potentiometric sensor, namely, PtHgHg 2 (Fur) 2 Graphite, where Fur stands for 4-chloro-N-furfuryl-5-sulphamoyl-anthranilate ion, are described. This electrode has a linear dynamic range between 5.0 × 10 -7 -1.0 × 10 -2 mol L -1 with a near-Nernstian slope of (-58.4± 0.9) mV decade -1 and a detection limit of 3.8 × 10 -7 mol L -1 . The potentiometric response is independent of the pH of the solution in the pH range 7.0-9.0. The electrode shows easy construction, low-cost, fast response time (within 10-20 s) and can be used for a period of 6 months without significant change in its performance characteristics. The proposed sensor displayed good selectivities over a variety of other anions (carboxylates and inorganic anions). Application of this potentiometric sensor for the furosemide determination in pharmaceuticals, urine, blood serum and commercial milk samples is reported.Keywords: 4-cloro-N-furfuryl-5-sulphamoylanthranilate-sensitive electrode, potentiometry, pharmaceuticals, urine, human blood serum, bovine milk IntroductionFurosemide or frusemide (HFur, 4-chloro-N-furfuryl-5-sulphamoyl-anthranilic acid) is formally a sulfonamide, an antibacterial agent (Figure 1). However, the intense and fast dieresis produced by this drug has extended its application as a powerful acidic diuretic for diverse treatments in humans and veterinary medicine. Furosemide is often classified as a loop diuretic due to its predominant action in the nephron, where the drug interferes with the tubular re-absorption of sodium on Henle's loop. 1 The renal excretion of ions is not limited to sodium and chloride, but it may also influence potassium, magnesium, calcium and, to a lesser extent, hydrogen carbonate ions. 2 In the clinical practice, the effects of furosemide are applied in the treatment of edema associated with pulmonary, cardiac, hepatic and renal disease, and of hypertension accompanied by fluid retention or impaired renal failure. 3-7 A marked diuresis is also associated to loss of weight, a side effect that has been incorrectly abused in the sport practice to achieve acute weight ...

“…In this work, the potential responses of the proposed Ag + membrane sensor to a wide variety of cations were investigated through the matched potential (MPM) 37 and separation solution method (SSM). 38 The resulting selectivity coefficient values obtained for the Ag + membrane electrode are summarized in Table 4. As it is seen, for alkali and alkali earth metal ions tested (Na + , K + , Ca 2+ ) the selectivity coefficients are less than 7.9 × 10 -6 .…”

Section: Evaluation Of Selectivity Coefficientsmentioning

confidence: 99%

Ion recognition: synthesis of 2-methyl-2,4-di (2-thienyl)-2,3-dihydro-1H-1,5-benzodiazepine and its application in construction of a highly selective and sensitive Ag+ membrane sensors

Ganjali¹,

Norouzi²,

Alizadeh³

et al. 2006

Uma membrana carregadora plastificada foi preparada a partir de 2-metil-2,4-di(2-tienil)-2,3-diidro-1H-1,5-benzodiazepina (MTHB). Esta membrana é altamente sensível e seletiva a íons Ag + . O sensor mostra um intervalo dinâmico linear de 1,0 × 10 -6 -1,0 × 10 -1 mol L -1 , com inclinação Nernstiniana de (58,5±0,3) mV per década, e limite de detecção 5,0 × 10 -7 mol L -1 (~54 ppb). Apresenta rápido tempo de resposta, 10s, e pode ser usado por 8 semanas no mínimo, sem alterações consideráveis no seu potencial. O sensor proposto pode ser usado no intervalo de pH entre 4,0 e 8,0 e foi utilizado com sucesso, como eletrodo indicador, na titulação potenciométrica de Ag + com NaCl.A highly selective and sensitive plasticized membrane sensor for Ag + ions based on 2-methyl-2,4-di(2-thienyl)-2,3-dihydro-1H-1,5-benzodiazepine (MTHB) as membrane carrier was prepared. The sensor shows a linear dynamic range of 1.0 × 10 -6 -1.0 × 10 -1 mol L -1 , with a Nernstian slope of (58.5±0.3) mV decade -1 , and a detection limit of 5.0 × 10 -7 mol L -1 (~54 ppb). It has a fast response time of 10 s and can be used for at least eight weeks without any considerable divergences in its potentials. The proposed sensor revealed very good selectivities with respect to the most of common metal ions. The proposed sensor could be used in a pH range of 4.0-8.0. It was successfully used as an indicator electrode in potentiometric titration of Ag + with NaCl.Keywords: potentiometric sensor, Ag + sensor, PVC membrane, 2-methyl-2,4-di(2-thienyl)-2,3-dihydro-1H-1,5-benzodiazepine (MTHB) IntroductionSilver plays no known natural biological role in humans, and possible health effects of silver are subject of dispute. Silver itself is not toxic but most of its salts are, and some may be carcinogenic. The toxicity of silver is characterized by a severe pulmonary edema, hemorrhage and necrosis of bone marrow, liver, and kidney. Long-term human exposure to silver salts or colloidal silver may cause argyria. Repeated exposure of animals to silver may produce anemia, cardiac enlargement, growth retardation and degenerative changes in the liver. Silver compounds were used successfully to prevent infection in World War I before the advent of antibiotics, and Silver compounds are still widely used externally today to accelerate healing in burn victims. Very low concentrations of silver are present in various complex samples like drinking water (5 μg L -1 , soil, rock, coal fly ash, air, cigarettes, alloys, plants, sea water etcetera). 1,2 Some techniques such as atomic absorption spectroscopy, 3 inductively coupled plasma, 4 spectroscopy with complexation agents 5 and Rayleigh light-scattering 6 have been used to determine amount of silver.Because of the increasing use of silver compounds in industry and medicine the quick determination of trace quantities of Ag + ion by simple methods is important in chemical, clinical and environmental analysis.Potentiometer monitoring based on ion-selective membrane sensor, as a simple method, offers several advantages such a...