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1.
Chemosphere ; 242: 125162, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31896189

RESUMO

The paper presents the quantitative characterization of the solid/water interface applying both experimental and theoretical approaches for the system of TiO2 (mixture of anatase and rutile) and Fe2O3 (maghemite) with calcium ions in the pH function. The aim of the study was also to find a bonding mechanism between Ca2+ and metal oxides surface based on the calculations from the surface complexation modeling code (GEOSURF by Sahai and Sverjensky, 1998). In order to obtain adsorption edges, a calcium ion-selective electrode (Ca-ISE) was applied for determination of Ca2+ concentration in the suspensions. The results of both the Ca-ISE and parallel spectrophotometric determination were similar. The adsorption data showed that TiO2 exhibited stronger calcium binding than Fe2O3 at pH > 8. Using 2-pK TLM (triple-layer model) it was demonstrated that mechanism of the calcium adsorption onto the metal oxides surface involved different reactions. In the case of TiO2 it involved formation of >SO-_CaOH+ predominately on the ß-plane and at pH > 9 also on the 0-plane. In the case of Fe2O3 one could observe the existence of (>SO-)2_Ca2+ on the ß-plane in the whole studied pH range. At pH above 7 the tetranuclear complexes (>SOH)2(>SO-)2_Ca(OH)+ were found, and at pH > 9 also >SO-_CaOH+ could be observed. On the other hand, the analysis of the ζ-potential data suggested the absence of the tetra-species on the maghemite surface. The study indicated that the properly validated calcium ion-selective electrode can be an attractive instrument for monitoring Ca2+ adsorption on metal oxides in the environment.


Assuntos
Cálcio/química , Modelos Químicos , Adsorção , Compostos Férricos/química , Concentração de Íons de Hidrogênio , Eletrodos Íon-Seletivos , Íons , Minerais/química , Óxidos/química , Titânio/química
2.
BMC Oral Health ; 19(1): 251, 2019 11 20.
Artigo em Inglês | MEDLINE | ID: mdl-31747894

RESUMO

BACKGROUND: The aim of this study was to compare free fluoride concentration and total fluoride concentration in mouthwashes. METHODS: Fluorine-containing mouthwashes from various companies and manufacturers (Colgate Total Plax Classic Mint®, Colgate-Palmolive, New York, USA; Colgate Total Plax Gentle Mint®, Colgate-Palmolive, New York, USA; Colgate Total Plax Fresh Mint®, Colgate-Palmolive, New York, USA; Oral B Advantage®, Procter&Gamble, Cincinnati, USA; Reach Fresh Mint®, Johnson&Johnson, New Brunswick, USA; Foramen®, Laboratorios Foramen, Guarnizo, Spain; Lacalut Sensitive®, Dr. THEISS, Homburg, Germany; Sensodyne®, GlaxoSmithKline, London, UK; Vesna F®, Vita, Saint Petersburg, Russia; Lacalut Fresh®, Dr. THEISS, Homburg, Germany) were selected as study objects. Fluoride measurements were carried out using the fluoride selective electrode. RESULTS: Free fluoride:total fluoride ratio was more than 80% for six samples (Colgate Total Plax Gentle Mint® - 88%, Colgate Total Plax Fresh Mint® - 99%, Oral B Advantage® - 92%, Reach Fresh Mint® - 92 and 89% for the mouthwash of another batch, Lacalut Sensitive® - 94%) and less than 63% for three samples (Colgate Total Plax Classic Mint® - 56%, Foramen® - 62%, Vesna F® - 61%). Two samples had more than 70% and less than 80% of unbound fluoride, respectively (Sensodyne® - 77%, another batch of Oral B Advantage® mouthwash - 74%). Rinse containing sodium monofluorophosphate (Na2PO3F) (Vesna F®) had more than 50% of free fluoride, while the rinse containing amine fluoride (AmF) (Lacalut Sensitive®) had 94%. The difference in the free fluoride:total fluoride ratio can be explained by binding of fluoride ions by components contained in mouthwashes, such as coloring agents and polymeric compounds. The lowest concentration of free fluoride ions (0.000093 mol/L) was observed for aluminum fluoride (AlF3) rinse (Lacalut Fresh®), while the total fluoride amount was not determined due to possible generation of strong fluoride complexes. This implies that fluoride ions will not be uptaken by tooth tissue and may even be washed away from it, compromising the efficacy of mouthwashes. CONCLUSIONS: The differences in free fluoride: total fluoride ratio between analyzed mouthwashes reveal a need to develop a method for evaluation of free fluorides in mouthwashes for proper updating of national and international guidelines.


Assuntos
Fluoretos/análise , Eletrodos Íon-Seletivos , Antissépticos Bucais/química , Potenciometria , Humanos
3.
Environ Monit Assess ; 191(12): 744, 2019 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-31720866

RESUMO

A heavy metal ion-selective electrode (ISE) with highly multiple response performances, rather than a high single response performance, is needed urgently for in situ, real-time environmental monitoring. In this study, we present an integrated measurement of six response performance variables such as the response slope, selectivity, dynamical range, detection limit, response time, and lifetime. They are selected and used as the indicators of the quality assessment for Pb2+-ISEs. The measurement, named as electrode comprehensive quality index (IECQ), is a single number for a given ISE. The comprehensive qualities of 114 Pb2+-ISEs reported in the literature were evaluated through the index method. Twenty-one Pb2+-ISEs-based polymer membrane with top 3 IECQ values for seven different properties have been recommended by evaluating and screening of the electrodes. Five Pb2+-ISEs-based polymer membrane with the best single response performance were also provided. The recommended Pb2+-ISEs, along with the corresponding Pb2+-ISEs with the miniaturized configurations, will provide helpful guideline for the application of Pb2+-ISE with highly multiple response performances in real-time environmental monitoring.


Assuntos
Monitoramento Ambiental/instrumentação , Eletrodos Íon-Seletivos , Chumbo/química , Eletrodos , Limite de Detecção , Polímeros
4.
Anal Bioanal Chem ; 411(29): 7605-7606, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31754766
5.
J Dairy Sci ; 102(8): 7435-7444, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31202658

RESUMO

A portable ion-selective electrode (ISE) meter (LAQUAtwin B-722; Horiba Instruments Inc., Irvine, CA) is available for measuring the sodium ion concentration ([Na]) in biological fluids. The objective of this study was to characterize the analytical performance of the ISE meter in measuring [Na] in whole-blood, plasma, milk, abomasal fluid, and urine samples from cattle. Method comparison studies were performed using whole-blood and plasma samples from 106 sick calves and 11 sick cows admitted to a veterinary teaching hospital, 80 milk and 206 urine samples from 16 lactating Holstein-Friesian cows with experimentally induced free water, electrolyte, and acid-base imbalances, and 67 abomasal fluid samples from 7 healthy male Holstein-Friesian calves fed fresh milk with or without an oral electrolyte solution. Deming regression and Bland-Altman plots were used to determine the accuracy of the meter against reference methods. The meter used in direct mode on undiluted samples measured whole-blood [Na] 9.7 mmol/L (7.3%) lower than a direct ISE reference method and plasma [Na] 16.7 mmol/L (12.7%) lower than an indirect ISE reference method. The meter run in direct mode measured milk [Na] 3.1 mmol/L lower and abomasal fluid [Na] 9.0% lower than indirect ISE reference methods. The meter run in indirect mode on diluted samples accurately measured urine [Na] compared with an indirect ISE reference method. We conclude that, after adjustment for the bias determined from Bland-Altman plots, the LAQUAtwin ISE meter provides a clinically useful and low-cost cow-side instrument for measuring [Na] in whole blood, plasma, milk, and abomasal fluid.


Assuntos
Abomaso/metabolismo , Doenças dos Bovinos/sangue , Eletrodos Íon-Seletivos , Leite/química , Sódio/análise , Animais , Bovinos , Doenças dos Bovinos/urina , Feminino , Lactação , Masculino , Plasma , Sódio/sangue , Sódio/urina
6.
Eur J Endocrinol ; 181(2): 193-199, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31167167

RESUMO

Background: Diagnosis and treatment of dysnatremia is challenging and further complicated by the pitfalls of different sodium measurement methods. Routinely used sodium measurements are the indirect (plasma/serum) and direct (whole blood) ion-selective electrode (ISE) method, showing discrepant results especially in the setting of acute illness. Few clinicians are aware of the differences between the methods in clinically stable patients or healthy volunteers. Methods: Data of 140 patients and 91 healthy volunteers undergoing osmotic stimulation with hypertonic saline infusion were analyzed. Sodium levels were measured simultaneously by indirect and direct ISE method before and at different time points during osmotic stimulation up to a sodium threshold of ≥150 mmol/L. The primary outcome was the difference in sodium levels between the indirect and direct ISE method. Results: 878 sodium measurements were analyzed. Mean (s.d.) sodium levels ranged from 141 mmol/L (2.9) to 151 mmol/L (2.1) by the indirect ISE compared to 140 mmol/L (3) to 149 mmol/L (2.8) by the direct ISE method. The interclass correlation coefficient between the two methods was 0.844 (95% CI: 0.823-0.863). On average, measurements by the indirect ISE were 1.9 mmol/L (95% CI limits: -3.2 to 6.9) higher than those by the direct ISE method (P < 0.001). The tendency of the indirect ISE method resulting in higher levels increased with increasing sodium levels. Conclusion: Intra-individual sodium levels differ significantly between the indirect and direct ISE method also in the absence of acute illness. It is therefore crucial to adhere to the same method in critical situations to avoid false decisions due to measurement differences.


Assuntos
Diabetes Insípido/sangue , Eletrodos Íon-Seletivos/normas , Polidipsia/sangue , Solução Salina Hipertônica/administração & dosagem , Sódio/sangue , Diabetes Insípido/diagnóstico , Humanos , Hipernatremia/sangue , Hipernatremia/induzido quimicamente , Hipernatremia/diagnóstico , Hiponatremia/sangue , Hiponatremia/diagnóstico , Polidipsia/diagnóstico , Estudos Prospectivos
7.
Rev. ADM ; 76(3): 133-140, mayo-jun. 2019. ilus, tab
Artigo em Espanhol | LILACS | ID: biblio-1021484

RESUMO

Introducción: Actualmente, existe una gran variedad de pastas dentales que se pueden encontrar en el mercado nacional, para diferentes propósitos. Entre éstas se hallan las empleadas para la prevención de caries. Éstas contienen fluoruro en diversas concentraciones como agente terapéutico, y casi en su totalidad estipulan en sus marbetes un contenido de 1,000 a 1,450 partes por millón (ppm) de fluoruro. Algunos estudios han mostrado que las concentraciones de fluoruro especificadas en la etiqueta y lo encontrado en el dentífrico no coinciden. Objetivo: Evaluar la concentración de fluoruro total con base en la Norma Mexicana NMX-K-539-CNCP-2013, que establece que los dentífricos no deben contener más de 1,500 ppm de fluoruro. Así como determinar si lo declarado en el marbete de sus empaques corresponde al contenido real de fluoruro. Material y métodos: El estudio se realizó, por triplicado, en 37 pastas dentífricas. El método para determinar la concentración de fluoruro fue el de ion selectivo, descrito por la Farmacopea de los Estados Unidos Mexicanos. Resultados: El promedio de concentración de este elemento fue de 1,262 ppm F- (± 170.7). El 59% de los dentífricos analizados no contienen la cantidad estipulada en el marbete. Conclusiones: Las concentraciones de fluoruro de los dentífricos se encuentran dentro de la Norma. Las concentraciones no corresponden a lo estipulado en el empaque (AU)


Introduction: Currently, there is a wide variety of toothpastes, which can be found in the national market, for different purposes. Among these are those used for the prevention of dental caries. These, contain fluoride in various concentrations as a therapeutic agent, and almost in their entirety, stipulate in their labels a content of 1,000 to 1,450 ppm of fluoride. Some studies have shown that the fluoride concentrations specified on the label, and what is found in the toothpaste do not match. Objective: To evaluate the concentration of total fluoride based on the Mexican Standard NMX-K-539-CNCP-2013, which establishes that toothpastes should not contain more than 1,500 ppm of fluoride. As well as determining if what is stated on the label of their packaging corresponds to the actual content of fluoride. Material and methods: The study was carried out, in triplicate, on 37 toothpastes. The method for determining the fluoride concentration was that of selective ion, described by the Pharmacopoeia of the United Mexican States. Results: The average concentration of this element was 1,262 ppm F- (± 170.7). Fifty nine percent of the dentifrices analyzed do not contain the amount stipulated in the label. Conclusions: The fluoride concentrations of dentifrices are within the Standard. The concentrations do not correspond to what is stipulated in the package (AU)


Assuntos
Dentifrícios/análise , Fluoretos/farmacologia , Epidemiologia Descritiva , Estudos Transversais , Análise Estatística , Eletrodos Íon-Seletivos , Cárie Dentária/prevenção & controle , Estudo Observacional , Concentração (Química) , México
8.
Sensors (Basel) ; 19(8)2019 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-31009998

RESUMO

Cystic Fibrosis (CF) is the most common fatal human genetic disease, which is caused by a defect in an anion channel protein (CFTR) that affects ion and water transport across the epithelium. We devised an apparatus to enable the measurement of concentration changes of sodium, potassium, chloride, pH, and transepithelial potential difference by means of ion-selective electrodes that were placed on both sides of a 16HBE14σ human bronchial epithelial cell line that was grown on a porous support. Using flat miniaturized ISE electrodes allows for reducing the medium volume adjacent to cells to approximately 20 µL and detecting changes in ion concentrations that are caused by transport through the cell layer. In contrast to classic electrochemical measurements, in our experiments neither the calibration of electrodes nor the interpretation of results is simple. The calibration solutions might affect cell physiology, the medium composition might change the direction of actions of the membrane channels and transporters, and water flow that might trigger or cut off the transport pathways accompanies the transport of ions. We found that there is an electroneutral transport of sodium chloride in both directions of the cell monolayer in the isosmotic transepithelial concentration gradient of sodium or chloride ions. The ions and water are transported as an isosmotic solution of 145 mM of NaCl.


Assuntos
Cloretos/isolamento & purificação , Células Epiteliais/metabolismo , Potássio/isolamento & purificação , Sódio/isolamento & purificação , Ânions/química , Cloretos/metabolismo , Células Epiteliais/química , Humanos , Concentração de Íons de Hidrogênio , Transporte de Íons , Eletrodos Íon-Seletivos , Potássio/metabolismo , Sódio/metabolismo , Migração Transendotelial e Transepitelial
9.
Environ Pollut ; 248: 958-964, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30861418

RESUMO

This study was initiated after the appearance of chlorotic and necrotic lesions on vegetation in the vicinity of a glassworks. The aim was to establish whether the cause was an uncontrolled release of gaseous fluorides. Five different plant species (Norway spruce, peach, common hornbeam, common bean, common grape vine) were collected in the influenced area, and the fluorine (F) content was determined by a fluoride ion selective electrode after prior total sample decomposition by alkaline carbonate fusion. The measurement results were reported together with their measurement uncertainties (MUs), which were evaluated according to the Guide to the Expression of Uncertainty in Measurement. The F contents at comparable distances from the emitter and in a clean area, free from natural or anthropogenic fluoride emissions, were 87-676 and 10 µg g-1, respectively, thereby confirming the release of gaseous fluorides from the glassworks. The F contents in samples of Norway spruce taken at various radial distances from the emitter suggest that the emitted gaseous fluorides were spread about evenly in all directions from the source following an inverse-power function. Estimated distances at which the F content would decrease to 50 µg g-1 (allowed maximum content of F in feeding stuffs) and 21 µg g-1 (maximum fluoride content in vegetables and fruits in relation to the upper limit of fluoride intake for humans) were 378 m and 571 m, respectively, from the emitter. Evaluation of our results for compliance with specification revealed a lack of regulation on fluoride content in the diet of humans and animals as well as a lack of guidelines on how to take into account MU.


Assuntos
Poluentes Atmosféricos/análise , Monitoramento Ambiental/métodos , Fluoretos/análise , Gases/análise , Regulamentação Governamental , Plantas/efeitos dos fármacos , Animais , Monitoramento Ambiental/legislação & jurisprudência , Política Ambiental/legislação & jurisprudência , Vidro , Humanos , Indústrias , Eletrodos Íon-Seletivos , Plantas/química , Eslovênia , Incerteza
10.
Aquat Toxicol ; 209: 168-177, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30784778

RESUMO

This study aimed to assess the sublethal effects of a platinum-based compound, cisplatin, using a zebrafish model. Zebrafish embryos were incubated in different concentrations of cisplatin at 0-96 h post-fertilization. Using a non-invasive, scanning ion-selective electrode technique (SIET), we measured the functions of hair cells (Ca2+ influx) and ionocytes ([H+] gradients). The survival rate, hatching rate, phenotype, body length, whole-body ion (Na+, Cl-, and Ca2+) and Pt contents were also determined. The effects of cisplatin on zebrafish embryos were demonstrated as first impairing hair cell function (at 1 µM of cisplatin), the hair cell number, and body ion content of Cl- (at 10 µM of cisplatin), then decreasing ionocyte acid secretion and overall body ion contents of Na+ and Ca2+ (at 50 µM of cisplatin). The body length and ionocyte density decreased at 100 µM of cisplatin, and survival decreased at 500 µM of cisplatin. As the cisplatin concentration increased, the accumulation of Pt in fish embryos also increased. These results revealed that hair cells are significantly more susceptible to cisplatin toxicity than ionocytes. By determining the lowest observed effective concentration of cisplatin that caused in vivo functional alterations of zebrafish hair cells and skin ionocytes, this model demonstrated 500-fold greater sensitivity than by detecting changes in survival, for early assessment of the effects of platinum-based chemotherapeutic drugs on fish.


Assuntos
Cisplatino/toxicidade , Embrião não Mamífero/patologia , Exposição Ambiental , Cabelo/patologia , Pele/patologia , Peixe-Zebra/embriologia , Animais , Cálcio/metabolismo , Cloretos/metabolismo , Embrião não Mamífero/efeitos dos fármacos , Eletrodos Íon-Seletivos , Íons , Sódio/metabolismo , Análise de Sobrevida , Peixe-Zebra/anatomia & histologia , Proteínas de Peixe-Zebra/metabolismo
11.
Invest Ophthalmol Vis Sci ; 60(2): 723-730, 2019 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-30786276

RESUMO

Purpose: The purpose of this study was to determine whether the ability of the rat retina to control its pH is affected by diabetes. Methods: Double-barreled H+-selective microelectrodes were used to measure extracellular [H+] in the dark-adapted retina of intact control and diabetic Long-Evans rats 1 to 6 months after intraperitoneal injection of vehicle or streptozotocin, respectively. Two manipulations-increasing of blood glucose and intravenous injection of the carbonic anhydrase blocker dorzolamide (DZM)-were used to examine their effects on retinal pH regulation. Results: An increase of retinal acidity was correlated with the diabetes-related increase in blood glucose, but only between 1 and 3 months of diabetes, not earlier or later. Adding intravenous glucose had no noticeable effect on the retinal acidity of control animals. In contrast, similar injections of glucose in diabetic rats significantly increased the acidity of the retina. Again, the largest increase of retinal acidity due to artificially elevated blood glucose was observed at 1 to 3 months of diabetes. Suppression of carbonic anhydrase by DZM dramatically increased the retinal acidity in both control and diabetic retinas to a similar degree. However, in controls, the strongest effect of DZM was recorded within 10 minutes after the injection, but in diabetics, the effect tended to increase with time and after 2 hours could be two to three times larger than at the beginning. Conclusions: During development of diabetes in rats, the control over retinal pH is partly compromised so that conditions that perturb retinal pH lead to larger and/or more sustained changes than in control animals.


Assuntos
Acidose/metabolismo , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Retinopatia Diabética/metabolismo , Retina/metabolismo , Animais , Glicemia/metabolismo , Adaptação à Escuridão , Eletrorretinografia , Concentração de Íons de Hidrogênio , Eletrodos Íon-Seletivos , Ratos , Ratos Long-Evans , Estreptozocina
12.
Sensors (Basel) ; 19(2)2019 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-30642018

RESUMO

Piperazine-based compounds bearing two phenylboronic acid or two benzoxaborole groups (PBPA and PBBB) were applied as dopamine receptors in polymeric membranes (PVC/DOS) of ion-selective electrodes. The potentiometric sensitivity and selectivity of the sensors towards dopamine were evaluated and compared with the results obtained for 2-phenylethylamine. Since the developed electrodes displayed strong interference from 2-phenylethylamine, single-molecule geometry optimizations were performed using the density functional theory (DFT) method in order to investigate the origin of dopamine/2-phenylethylamine selectivity. The results indicated that phenylboronic acid and benzoxaborole receptors bind dopamine mainly through the dative B⁻N bond (like 2-phenylethylamine) and the potentiometric selectivity is mainly governed by the higher lipophilicity of 2-phenylethylamine.


Assuntos
Técnicas Biossensoriais/métodos , Dopamina/isolamento & purificação , Fenetilaminas/isolamento & purificação , Potenciometria/métodos , Boro/química , Ácidos Borônicos/química , Dopamina/química , Eletrodos Íon-Seletivos , Membranas Artificiais , Fenetilaminas/química , Piperazina/química , Cloreto de Polivinila/química
13.
Artigo em Inglês | MEDLINE | ID: mdl-30236454

RESUMO

To examine Ca2+ absorption and transportation in the freshwater pearl oyster, Hyriopsis cumingii Lea, we studied the effects of different levels of either extracellular Ca2+ or 1,25(OH)2D3 on extracellular Ca2+ flux and intracellular Ca2+ concentrations in mantle cells using the non-invasive micro-test technique and laser scanning confocal microscopy. The inner and outer mantle (IM and OM) cells from mussels were cultured and then treated with different concentrations of Ca2+ and 1,25(OH)2D3. Extracellular Ca2+ flux and intracellular Ca2+ reserves were analyzed. The results showed that both extracellular Ca2+ and 1,25(OH)2D3 had significant effects on Ca2+ flux and reserves in mantle cells, especially in IM cells (P < .05). The increase in extracellular Ca2+ concentrations resulted in the conversion of extracellular Ca2+ flux into influx with an increase in flow rate (P < .05). The calcium ion fluorescence intensity of OM cells was higher than that of IM cells (P < .05). 1,25(OH)2D3 addition also significantly increased the influx rate of extracellular Ca2+, especially in IM cells, which were more sensitive to 1,25(OH)2D3 addition and had significantly higher Ca2+ influx rates than did OM cells (P < .05). Fluorescence intensities of intracellular Ca2+ first increased and then decreased with increasing 1,25(OH)2D3 levels. The study showed that IM cells play an important role in absorbing Ca2+ from the environment, while OM cells mainly function in the temporary storage and transportation of Ca2+ in the body. The current results suggested that high levels of extracellular Ca2+ (1.25 mM) or 1,25(OH)2D3 (over 100 IU/L) were favorable for Ca2+ uptake and maintenance in the body.


Assuntos
Absorção Fisiológica , Exoesqueleto/metabolismo , Calcitriol/metabolismo , Sinalização do Cálcio , Cálcio/metabolismo , Pinctada/fisiologia , Exoesqueleto/citologia , Animais , Aquicultura , Transporte Biológico , Células Cultivadas , China , Corantes Fluorescentes/química , Eletrodos Íon-Seletivos , Cinética , Microscopia Confocal , Pinctada/crescimento & desenvolvimento , Reprodutibilidade dos Testes
14.
J AOAC Int ; 102(3): 794-800, 2019 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-30446018

RESUMO

Background: Traditional methods for Lomefloxacin hydrochloride (LOM) determination involve pretreatment steps, which extend analysis time and use hazardous chemicals. Objective: The ability to provide a rapid route without sample pretreatment for quantitative determination of compounds via a low-cost instrument is a challenging task. In this work, a simple potentiometric method was developed to determine the antibacterial LOM via in-house fabricated ion selective electrodes. Methods: Different sensors were fabricated using a poly vinyl chloride-based membrane, potassium tetrakis(4-chlorophenyl) borate as a cation exchanger, and 2-Nitrophenyl octyl ether as a plasticizer (sensor 1). To increase the selectivity of sensor 1, a selective molecular recognition component 2-hydroxypropyl-ß-cyclodextrin was used as ionophore (sensor 2). Results: The proposed method was validated according to International Union of Pure and Applied Chemistry recommendations, in which the proposed sensors show a linear dynamic range from 1 × 10-5 to 1 × 10-2 mol/L, with Nernstian slopes of 55.829 and 58.229 mV/decade for sensors 1 and 2, respectively. It was applied to determine LOM in bulk powder, in different dosage forms, and in plasma with no sample pretreatment. Also, the suggested method can be used as a green, in-line bench top real-time analyzer for in-process monitoring of LOM release from its tablets, under U.S. Food and Drug Administration dissolution regulations, with clear discrimination from common excipients. Results obtained by the proposed potentiometric method were compared with those obtained by a reported HPLC method. Conclusions: The proposed method is considered as a perfect alternative to traditional reported methods for LOM determination.


Assuntos
Antibacterianos/sangue , Fluoroquinolonas/sangue , Química Verde/métodos , 2-Hidroxipropil-beta-Ciclodextrina/química , Antibacterianos/administração & dosagem , Cromatografia Líquida de Alta Pressão/normas , Éteres/química , Fluoroquinolonas/administração & dosagem , Química Verde/instrumentação , Química Verde/normas , Humanos , Eletrodos Íon-Seletivos , Ionóforos/química , Limite de Detecção , Soluções Oftálmicas/análise , Plastificantes/química , Cloreto de Polivinila/química , Potenciometria/instrumentação , Potenciometria/métodos , Potenciometria/normas , Comprimidos/análise , Tetrafenilborato/análogos & derivados , Tetrafenilborato/química
15.
Dent Mater ; 35(1): 135-143, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30502961

RESUMO

OBJECTIVE: The aim of this study was to determine whether there is a correlation between acid erosion and fluoride release of conventional glass ionomer cements. METHODS: Ten specimens for each material were prepared for fluoride release tests and five for acid erosion tests separately. After placed in pH cycling solution, concentration of fluoride was measured by a fluoride-ion selective electrode each day for 15 days. For the acid erosion test, specimens were immersed in a lactic acid solution and their depth measured with a spring-loaded dial gauge. The data were submitted to 3-way ANOVA, followed by Tukey's test (p<0.05) RESULTS: All materials showed ability to elute fluoride in the 15 day period of the test, with the same pattern of high fluoride release at the first 24h. Despite this, the amount of fluoride released was statistically different among the 18 groups, with the highest for Maxxion R and the lowest for Chemfil Rock (p>0.05). The highest acid erosion values were registered for Magic Glass, Ion Z, VitroFil and Maxxion R, which exceeded the maximum stipulated by the relevant ISO test (ISO 9917-1). A positive linear correlation (r2=0.4886) was found for both properties, i.e., higher fluoride release is related to higher acid erosion. SIGNIFICANCE: Acid erosion and fluoride release are related properties of GICs, though factors such as pH and P/L ratio lead to differences between actual values for individual brands of these materials.


Assuntos
Fluoretos , Cimentos de Ionômeros de Vidro , Eletrodos Íon-Seletivos , Teste de Materiais
16.
PLoS One ; 13(12): e0207782, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30513099

RESUMO

An in vitro gut-sac technique and the scanning ion-selective electrode technique (SIET) were used to characterize Mg2+, Ca2+, and H+ transport at both the mucosal and serosal surfaces of non-everted and everted gastrointestinal tissues obtained from Carassius auratus. As part of the study, two magnesium ionophores were compared (II vs. VI). Unfed animals displayed uniform transport of all ions along the intestine. Feeding resulted in elevated Mg2+ and Ca2+ transport when the gut lumen contained chyme however, under symmetrical conditions this increased transport rate was absent. Furthermore, zonation of divalent cation transport was present for both Ca2+ and Mg2+ under non-symmetrical conditions while the zonation remained for Ca2+ alone under symmetrical conditions. High dietary Mg2+ decreased absorption and induced secretion of Mg2+ in the posterior intestine. Uptake kinetics in the esophagus suggest large diffusive and/or convective components based on a linear relationship between Mg2+ transport and concentration and lack of inhibition by ouabain, an inhibitor of Na+-K+-ATPase. In contrast, kinetics in the rectum were suggestive of a low affinity, saturable carrier-mediated pathway. A decrease in Mg2+ and Ca2+ transport was observed in the posterior intestine (both at the mucosal and serosal surfaces) in response to ouabain. This impact was greatest for Ca2+ transport and when applied to the mucosal fluid and measured in everted preparations. In contrast a putative Mg2+ transport inhibitor, cobalt(III)hexamine-chloride, did not affect Mg2+ transport. This is the first study to use SIET approaches to study ion transport in the gut of teleost fish. This is also the first study to provide characterization of Mg2+ transport in the gut of C. auratus. Due to the limited selectivity of Magnesium ionophore II, subsequent studies of tissues bathed in physiological saline should be made using Magnesium Ionophore VI.


Assuntos
Cálcio/metabolismo , Trato Gastrointestinal/metabolismo , Carpa Dourada/metabolismo , Magnésio/metabolismo , Animais , Esôfago/efeitos dos fármacos , Esôfago/metabolismo , Trato Gastrointestinal/efeitos dos fármacos , Técnicas In Vitro , Transporte de Íons/efeitos dos fármacos , Eletrodos Íon-Seletivos , Ionóforos/farmacologia , Cinética , Ouabaína/farmacologia , Prótons , Reto/efeitos dos fármacos , Reto/metabolismo
17.
Invest Ophthalmol Vis Sci ; 59(12): 4841-4846, 2018 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-30347078

RESUMO

Purpose: Reactive and underfluorinated impurities are acknowledged as a source of cytotoxicity of perfluorocarbon liquids (PFCLs) used as blood substitutes. To determine whether this is also a relevant factor in retinal toxicity, we analyzed eight PFO batches associated with adverse ocular events. Methods: (A) The amount of reactive and underflurinated impurities was analyzed by fluoride-selective potentiometry and expressed as H-value. (B) Cytotoxicity of these batches was determined by an ISO 10993-5-compliant extractive test and compared to published data generated with a direct-contact method. (C) A toxic PFO batch (061014) was purified to remove reactive and underfluorinated impurities. (A) and (B) -measurements were repeated after that. (D) The dose dependence of the H-value and cytotoxicity was determined in a dilution experiment. Results: (A) The batches revealed H-values ranging from 1.400 ppm to 4.500 ppm. (B) All batches induced cell growth inhibition; seven must be classified as cytotoxic. Findings from ISO-conform extractive and direct-contact methods showed no difference. (C) After all reactive and underfluorinated impurities in batch 061014 were removed, the H-value dropped to <10 ppm and cytotoxicity disappeared. (D) Cytotoxicity increases gradually as the H-value rises. Conclusions: The clinical relevance of the H-value as a safety parameter for PFO endotamponades could be proven. The H-value is a measure for reactive and underfluorinated impurities that cause toxicity of PFCLs and should be incorporated in each endotamponade specification with a limit of 10 ppm to prove the effectiveness of the ultra-purification required and ensure a safe product. Despite the fact that an (ISO)-standard literally is a "standard" only, which cannot cover all imaginable possibilities, the incorporation of the H-value determination into the relevant ISO standard has been initiated. If a thorough risk assessment results in risks that cannot be detected and/or managed by the effective standard, additional investigations have to be performed.


Assuntos
Fibroblastos/efeitos dos fármacos , Fluoretos/análise , Fluorcarbonetos/toxicidade , Eletrodos Íon-Seletivos , Potenciometria/métodos , Retina/efeitos dos fármacos , Doenças Retinianas/prevenção & controle , Animais , Substitutos Sanguíneos/toxicidade , Tamponamento Interno , Fibroblastos/patologia , Camundongos , Doenças Retinianas/induzido quimicamente
18.
Clin Lab ; 64(9): 1457-1467, 2018 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-30274000

RESUMO

BACKGROUND: Chloride is the main anion in human body. A simple and accurate method for serum chloride measurement was developed using ion chromatography (IC) in China. METHODS: In the measurement, serum samples were diluted 500 times with water, filtered and injected into ion chromatography column. A mixed eluent (2 mmol/L CO32- + 12 mmol/L OH-) was used and peak area signal was collected. Five calibrators made from Standard Reference Material (SRM) 919b were used in the bracketing method. The IC method was applied as the comparative method and six ion selective electrode (ISE) measurement systems were evaluated using 60 individual patient serums. RESULTS: The IC method was proven to be accurate. The precision was 0.18% - 0.30%, the recovery was 99.66% - 100.60%, the bias was 0.19% to -0.06%, and the related expanded uncertainty was 0.775% (k = 2). The precisions of the ISE systems were smaller than the 0.9% tolerable CV except for the Beckman DXC (0.91% - 1.16%). In comparison, the results of linear regression analysis showed that the correlation coefficients were 0.9876 to 0.9979. For all systems, the range of mean biases was -5.96 - 1.48 mmol/L (-5.57% - 1.36%); the expected biases at the medical decision levels were -4.97% - 0.84% at 90 mmol/L and -6.02% - 1.76% at 120 mmol/L. All biases of the Beckman AU met the requirement of within ± 1.5%. CONCLUSIONS: The IC measurement method is proven to be of high precision and trueness, and the quality of routine ISE measurement of serum chloride still needs significant improvement. The establishment of the IC method can improve the measurement quality and promote its standardization process in China.


Assuntos
Cloretos/sangue , Cromatografia Líquida/métodos , Eletrodos Íon-Seletivos , Viés , Calibragem , China , Cromatografia Líquida/normas , Desenho de Equipamento , Humanos , Eletrodos Íon-Seletivos/normas , Variações Dependentes do Observador , Padrões de Referência , Reprodutibilidade dos Testes
19.
Artigo em Chinês | MEDLINE | ID: mdl-30248752

RESUMO

Objective: To optimize the ion selective electrode method of measuring urinary fluorine in WS/T 30-1996. Methods: The volume of 5 mol/L NaOH solution was fixed to confect the TISAB buffer solution. The samples were prepared by mixing 5 ml urine and equal volume of TISAB solution. Fluorine electrode and calomel electrode was used to test. When the potential value changed less than ±0.5 mV in one minute, it could be recorded. The standard curve method was selected as a quantitive method. Results: The linear range of this method was 0.07~50.0 mg/L, E=238.96-57.50lgC, r=0.999 8. The LOD and LOQ were 0.02 mg/L and 0.07 mg/L (with 5 ml urine) , respectively. The RSD of intra -and inter-batch precision were 0.80%~2.82% and 2.17%~2.86%, respectively. The recovery rate was 102%~107%. The urine sample could be preserved stably for 14 days at room temperature, and for 30 days at 4 ℃ and -20 ℃. Conclusion: In this method, the preparation process of TISAB buffer solution was simplified, and the linear range was expanded. It could meet the needs of occupational population detection.


Assuntos
Flúor/urina , Eletrodos Íon-Seletivos , Humanos
20.
PLoS One ; 13(9): e0203862, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30252859

RESUMO

Small-holding farmers in the developing world suffer from sub-optimal crop yields because they lack a soil diagnostic system that is affordable, usable, and actionable. This paper details the fabrication and characterization of an integrated point-of-use soil-testing system, comprised of disposable ion-selective electrode strips and a handheld electrochemical reader. Together, the strips and reader transduce soil ion concentrations into to an alphanumeric output that can be communicated via text message to a central service provider offering immediate, customized fertilizer advisory. The solid-state ion-selective electrode (SS-ISE) strips employ a two-electrode design with screen-printable carbon nanotube ink serving as the electrical contacts for the working and reference electrodes. The working electrode comprises a plasticizer-free butyl acrylate ion-selective membrane (ISM), doped with an ion-selective ionophore and lipophilic salt. Meanwhile, the reference electrode includes a screen-printed silver-silver chloride ink and a polyvinyl-butyral membrane, which is doped with sodium chloride for stable reference potentials. As a proof of concept, potassium-selective electrodes are studied, given potassium's essential role in plant growth and reproduction. The ISE-based system is reproducibly manufactured to yield a Nernstian response with a sub-micromolar detection limit (pK+ of 5.18 ± 0.08) and near-Nernstian sensitivity (61 mV/decade) in the presence of a 0.02 M strontium chloride extraction solution. Analysis of soil samples using the printed electrodes and reader yielded a correlation coefficient of 𝑅2 = 0.89 with respect to values measured via inductively coupled plasma atomic emission spectroscopy (ICP-AES). The reliable performance of this system is encouraging toward its deployment for soil nutrient management in resource-limited environments.


Assuntos
Potenciometria/instrumentação , Solo/química , Eletrodos , Equipamentos e Provisões , Eletrodos Íon-Seletivos , Limite de Detecção , Potenciometria/métodos
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