Ömer IŞILDAK | Gaziosmanpasa University (original) (raw)
Papers by Ömer IŞILDAK
Journal of The Chinese Chemical Society, Jun 16, 2023
BackgroundIonophores in the composition of potentiometric ion‐selective electrodes interact direc... more BackgroundIonophores in the composition of potentiometric ion‐selective electrodes interact directly with the analyte ion and enable the determination of ionic species in various samples.ObjectivesIn this study, a novel ion‐selective electrode based on 5‐bromosalicylaldehyde thiosemicarbazone was developed for the selective determination of Cr3+ ions.MethodsThe optimum electrode composition contained ionophore, poly (vinyl chloride) (PVC), bis (2‐ethylhexyl) sebacate (BEHS) and potassium tetrakis (p‐chlorophenyl) borate (KTpClPB) in ratios of 4.0: 61.0: 34.0: 1.0 (mg), respectively. Potential measurements were performed using a computer‐controlled multi‐channel potentiometric measurement system.ResultsThe developed Cr (III)‐selective electrode exhibited a low detection limit of 3.96 × 10−6 M over a wide concentration range of 1.0 × 10−5 – 1.0 × 10−1 M (R2: 0.9979). The electrode exhibited good selectivity towards Cr3+ ions among metal ions with different charges. The chromium (III)‐selective electrode, which exhibited highly reproducible results in three different concentration ranges, also had a very fast response time of 5 s.ConclusionsThe developed Cr (III)‐selective electrode were successfully performed in various beverage samples. As a result, the proposed electrode can be an alternative to other analytical methods in the analysis of Cr3+ ions.
DergiPark (Istanbul University), Dec 31, 2021
In this study, a novel all-solid-state contact poly(vinylchloride) (PVC) membrane potassium selec... more In this study, a novel all-solid-state contact poly(vinylchloride) (PVC) membrane potassium selective sensor with a pyrazole derivative molecule as an ionophore has been developed. The potassium selective sensor has a composition of PVC, ionophore, anion excluder (potassium tetrakis (p-chlorophenyl)borat (KTpClPB)) and plasticizer (bis(2ethylhexyl)adipate (DEHA)) in the ratio of 32.0:4.0:1.0:63.0 (mg). The potassium selective sensor works in a linear concentration range of 1.0×10-5 to 1.0×10-1 M with a low detection limit of 6.02 × 10 −6 M The developed potassium selective sensor works in pH range of 6.0-10.0 and has good repeatability, selectivity and a short response time of 10 seconds. Finally, the developed potassium selective sensor was successfully used in the determination of potassium in tap water and a drug sample. Bu çalışmada, pirazol türevi bir molekülünün iyonofor olarak kullanıldığı yeni tümüyle katı hal kontak poli(vinilklorür) (PVC) membran potasyum sensörü geliştirildi. Potasyum seçici sensör PVC, iyonofor, potasyum tetrakis (p-klorofenil)borat (KTpClPB)) ve plastikleştirici (bis (2-etilheksil)adipat (DEHA))'ın 32.0:4.0:1.0:63.0 (mg)'lık bileşimine sahiptir. Geliştirilen potasyum seçici sensör, 6.02×10-6 M'lık düşük algılama limiti ile 1.0×10-5-1.0×10-1 M konsantrasyon aralığında doğrusal olarak çalışmaktadır. Geliştirilen potasyum seçici sensör pH 6.0-10.0 aralığında çalışmaktadır, iyi tekrarlanabilirlik, iyi seçicilik ve 10 saniyelik kısa cevap zamanına sahiptir. Son olarak, geliştirilen potasyum seçici sensör musluk suyu ve ilaç örneğinde potasyum tayininde başarıyla kullanılmıştır.
Social Science Research Network, 2022
International Journal of Environmental Analytical Chemistry, Feb 4, 2021
Ion-selective electrodes or sensors are preferred by researchers in the determination of various ... more Ion-selective electrodes or sensors are preferred by researchers in the determination of various ions since they provide very high selectivity and wide concentration range in environmental, industr...
ChemistrySelect, Jan 18, 2022
A poly(vinyl chloride) (PVC) membrane potentiometric sensor was developed for the determination o... more A poly(vinyl chloride) (PVC) membrane potentiometric sensor was developed for the determination of anti‐epileptic drug levetiracetam. For this purpose, levetiracetam‐tetraphenylborate (LEV‐TPB) ion‐pair was synthesized and the synthesized ion‐pair was used as ionophore in PVC membrane structures. The membrane composed of 3.0 % (w/w) LEV‐TPB ion‐pair, 32.0 % (w/w) PVC, and 65.0 % (w/w) o‐nitrophenyloctylether (o‐NPOE) was determined as the membrane with the best potentiometric properties. The developed sensor exhibited a linear response in the concentration range from 1.0×10−5 to 1.0×10−1 mol L−1 and had a detection limit of 6.31×10−6 mol L−1. For this sensor, pH working range and response time were determined as 6.0–8.0 and ≈25 s, respectively. The sensor displayed a good selectivity for levetiracetam in the presence of a number of common ionic species and some anti‐epileptic drug. The proposed levetiracetam‐selective sensor was successfully applied for the determination of levetiracetam in pharmaceutical drug samples which is used in the treatment of epilepsy.
Organic communications, Sep 19, 2021
Potentiometric methods are a type of electrochemical analysis which are used widely in many appli... more Potentiometric methods are a type of electrochemical analysis which are used widely in many applications due to their multiple advantages such as wide concentration range, low detection limit, high selectivity, and sensitivity. Potentiometric sensors have many advantages over the other analytical methods and have been successfully applied in different real sample analyzes. Crown ethers are a group of macrocyclic compounds and have been used as ionophores by researchers due to their favorable chemical structures. In this review, we provide a description on crown ethers used as ionophores in potentiometric sensors.
Critical Reviews in Analytical Chemistry, Sep 29, 2020
Potentiometry is extensively studied by researchers as one of the electrochemical methods due to ... more Potentiometry is extensively studied by researchers as one of the electrochemical methods due to its multiple advantages. Until today, thousands of potentiometric sensors have been developed and applied successfully in many fields such as medicine, environmental monitoring, agriculture, industry and pharmaceutical sciences. Clinical drug analyses and determination of drugs in biological samples are highly important from a medical point of view. These analyses are carried out using various analytical devices including potentiometric sensors. These potentiometric sensors are superior to other devices in terms of several performance parameters, and thus present a good alternative for researchers. Using potentiometric sensors, very successful results in the identification of drug molecules in body fluids have been obtained and reported in the literature up to now. In this study, we review potentiometry-based sensors developed for the determination of drug molecules in various biological samples such as blood serum and urine, and touch upon their performance features in these applications.
Critical Reviews in Analytical Chemistry, Jan 13, 2020
Potentiometry is one of the most important electrochemical methods and potentiometric based senso... more Potentiometry is one of the most important electrochemical methods and potentiometric based sensors have been extensively studied by researchers for many years. The fact that potentiometric sensors have several advantages over other analytical devices is another reason for intensive research on the topic. In this area, hundreds of different sensors have been developed till today and introduced into the literature. The successful use of the developed sensors, particularly in real sample analysis, has made potentiometric sensors the center of attention. In this review, we highlight the studies which have been successfully applied to the developed drug samples and also to many real samples, with high recovery rates.
Hacettepe University Journal of the Faculty of Pharmacy, Apr 20, 2022
The Use of Valproic Acid in the Treatment of Epilepsy and Determination of Biological Matrices Re... more The Use of Valproic Acid in the Treatment of Epilepsy and Determination of Biological Matrices Review Article ÖZET Epilepsi kronik nörolojik bir hastalıktır ve tedavisi uzun süreli veya ömür boyu sürmektedir. Anti-epileptik ilaçlar epilepsi tedavisinde kullanılan önemli farmakolojik ajanlardır. Epilepsi tedavisinde kullanılmak üzere seçilen anti-epileptik ajan, mümkün olduğunca az yan etkiye sahip olmalı ve nöbet gelişimini engellemelidir. Valproik asit neredeyse tüm epileptik nöbetlerin tedavisinde oldukça etkili olan geniş spektrumlu bir ilaçtır. Güvenilir profili nedeniyle dünya genelinde oldukça yaygın olarak kullanılmaktadır. Tedavi boyunca insan kanındaki valproik asidin terapötik seviyesi izlenmelidir. Bu nedenle, çeşitli analitik yöntemler kullanılarak farklı biyolojik örneklerde valproik asit test prosedürleri önerilmiştir. Bu derlemede, biyolojik örneklerde valproik asidin tayinine yönelik bildirilen analitik metotlar ve bu metotların performans özelliklerine değinilmiştir.
Bulletin of Materials Science, Jun 27, 2022
ChemistrySelect, Sep 1, 2022
In this study, a novel PVC‐based membrane containing (E)‐2‐(1‐(4‐(3‐(4‐chlorophenyl)ureido)phenyl... more In this study, a novel PVC‐based membrane containing (E)‐2‐(1‐(4‐(3‐(4‐chlorophenyl)ureido)phenyl)ethylidene)hydrazine carbothioamide (5) as an electroactive component (ionophore) along with potassium tetrakis (p‐chlorophenyl) borate (KTpClPB) and bis(2‐ethylhexyl)adipate (DEHA) in the ratio 4.0 : 32.0 : 1.0 : 63.0 (ionophore:PVC:KTpClPB:DEHA) (w/w) was used to develop a lead(II)‐selective potentiometric sensor. The sensor exhibited a Nernstian response over a wide concentration range from 1.0×10−5 to 1.0×10−1 mol L−1 with a slope of 28.0±2.0 mV/decade, and a detection limit of 1.65×10−6 mol L−1. It displayed very good selectivity towards Pb(II) ions over other cationic species. The lead(II)‐selective sensor showed a fast response time of 5 s, good repeatability, and it worked in the broad pH range of 5.0–11.0. The sensor could be used as an indicator electrode in the quantification of Pb(II) by potentiometric titration against ethylenediaminetetraacetic acid (EDTA). In addition, this sensor was applied for the direct determination of Pb(II) in different water samples including spring water, purification water, commercial water, waste water and in a waste battery sample.
Journal of Chemical Sciences, Jan 25, 2020
In this study, all-solid-state contact PVC membrane silver(I)-selective sensor has been prepared ... more In this study, all-solid-state contact PVC membrane silver(I)-selective sensor has been prepared and 5,10,15,20-tetra(4-pyridyl)-21H,23H-porphine used as ionophore. Optimum membrane composition; 3.5% ionophore, 59.6% Bis(2-ethylhexyl) sebacate (BEHS), 1.0% potassium tetrakis (p-chlorophenyl) borate (KTpClPB) and 35.9% polyvinyl chloride (PVC). The developed silver(I)-selective sensor exhibited a linear response (E =-51,57 (-log[Ag ? ]) ? 1690,6 and R 2 = 0,9986) in the varying concentration range of 1.0 9 10-1 to 1.0 9 10-5 mol L-1 silver ions. The limit of detection of the sensor was calculated as 1.9 9 10-6 mol L-1. The silver(I)-selective sensor exhibited good selectivity towards some alkali, alkali earth and heavy metal ions. The sensor can be used in the pH range from 4.0 to 10.0. The sensor has been shown to have good reusability and response time less than 8 s. The sensor was used as an indicator electrode in titrations of silver nitrate with sodium chloride solution and was successfully applied for the determination of the different water samples.
Journal of inclusion phenomena and macrocyclic chemistry, Jul 27, 2020
Porphyrins are a group of macrocyclic compounds which are widely used in many applications in the... more Porphyrins are a group of macrocyclic compounds which are widely used in many applications in the literature due to their multiple functions. One of their application areas is in the development of sensors which transform changes in physical and chemical parameters into electrical signals. Novel chemical sensors selective and sensitive for many anions and cations have been fabricated with the advancements in the technology. Real sample applications of these sensors can be successfully performed. In recent years, potentiometric methods have drawn researchers' attention and they have been highly studied because of their superiority over other analytical devices. Ionophores which are used in the development of potentiometric sensors and ion-selective electrodes are the most important components of these systems. Therefore, porphyrin molecules, which have favorable chemical structures, can be directly used as an active component (ionophore) in the structure of potentiometric sensors. In this review, we investigated porphyrin derivatives used as ionophore in the design of potentiometric sensors and we focused on newly developed potentiometric sensors based on porphyrin.
Journal of Hazardous Materials, Jul 31, 2006
Adsorption equilibrium of stearic acid onto natural bentonite with Turkish origin was studied at ... more Adsorption equilibrium of stearic acid onto natural bentonite with Turkish origin was studied at the temperatures of 298, 308 and 318 K. SEM and XRD analysis show that the bentonite used as adsorbent is composed of microcrystal and porous structure. The specific surface area was determined by BET method as 38.6 m 2 /g. The adsorption of stearic acid onto bentonite was conformed to the Langmiur and Freundlich isotherms. The equilibrium parameter, R L revealed that the bentonite is a good adsorbent for stearic acid. The sorption capacity of bentonite studied decreases with increasing temperature. However, it is concluded that the adsorption capacity of bentonite for the stearic acid under the same experimental conditions is in comparable level in terms of that of the rice husk ash given in literature. Thermodynamic parameters, G • ads , was calculated to be between −21.8 and −22.8 kJ mol −1. H • ads and S • ads were found to be −9.2 kJ mol −1 and 42.4 J mol −1 K −1 , respectively. These parameters obtained as a function of temperature indicate that the adsorption of stearic acid onto bentonite was a spontaneous and an exothermic process. An FT-IR study on the adsorbed material was used to verify the interaction of the stearic molecule with bentonite after adsorption process.
Journal of the Indian Chemical Society, May 1, 2022
Journal of Analytical Chemistry, Dec 1, 2009
... 11. Buck, CF, Mayewski, PA, Spencer, MJ, Whitlow, S., Twickler, MS, and Barrett, D., J. Chrom... more ... 11. Buck, CF, Mayewski, PA, Spencer, MJ, Whitlow, S., Twickler, MS, and Barrett, D., J. Chromatogr. A, 1992, vol. 594, p. 225. 12. Isildak, I. and Covington, AK, Electroanal., 1993, vol. 5, p. 815. 13. Hong, US, Kwon, HK, Nam, H., Cha, GS, Kwon, KH, and Peang, KJ, Anal. Chim. ...
![Research paper thumbnail of Development of calcium-selective potentiometric electrode using 10,19- Bis[(octadecylcarbamoyl)methoxyacetyl]-1,4,7,13,16-pentaoxa-10,19- diazacycloheneicosane compound as ionophore](https://attachments.academia-assets.com/113092151/thumbnails/1.jpg)
](International journal of chemistry and technology, Dec 28, 2018
This work deals with the development of micro-size potentiometric calcium-selective electrode. A ... more This work deals with the development of micro-size potentiometric calcium-selective electrode. A simple and rapid potentiometric method of determining calcium concentration, based on 10,19-Bis[(octadecylcarbamoyl) methoxyacetyl]-1,4,7,13,16-pentaoxa-10,19-diazacycloheneicosane, is described. For this aim, calcium-selective polyvinylchloride (PVC) membrane was prepared by coating on the surface of solid-contact. Calcium-selective PVC membrane electrode does not contain internal reference electrode and solution. The potentiometric performance of calcium-selective PVC membrane electrode (selectivity constant, liner working range, detection limit, response time, pH working range, repeatability, lifetime, and time dependent potential decay) was determined using computer controlled measurement system in static conditions. The results showed that the calcium-selective electrode exhibited good reproducibility in calcium determination.
Journal of The Chinese Chemical Society, Jun 7, 2022
A novel poly(vinyl chloride; PVC) membrane‐based Cu(II)–selective sensor has been developed using... more A novel poly(vinyl chloride; PVC) membrane‐based Cu(II)–selective sensor has been developed using synthesized 5,10,15,20‐tetrakis(4‐methoxycarbonylphenyl)porphyrin as an ionophore. The Cu(II)–selective sensor exhibits a Nernstian response for Cu(II) ion over a wide concentration range of 1.0 × 10−5 to 1.0 × 10−1 mol L−1 with the slope of 27.0 ± 2.5 mV/decade, and a lower limit of detection of 1.88 × 10−6 mol L−1. The novel sensor shows good repeatability and high selectivity for Cu(II) ions over other mono‐, bi‐ and trivalent cations. The sensor potential response remains unaffected by pH in the range of 4.4–10.6 and exhibits a fast response time of less than 10s. Finally the developed Cu(II)–selective sensor has been successfully used as an indicator electrode in the potentiometric titration of Cu2+ against ethylenediaminetetraacetic acid and also in the determination of Cu(II) ion concentration in different water and beverage samples.
Chemical Papers, Jul 17, 2023
Journal of The Chinese Chemical Society, Jun 16, 2023
BackgroundIonophores in the composition of potentiometric ion‐selective electrodes interact direc... more BackgroundIonophores in the composition of potentiometric ion‐selective electrodes interact directly with the analyte ion and enable the determination of ionic species in various samples.ObjectivesIn this study, a novel ion‐selective electrode based on 5‐bromosalicylaldehyde thiosemicarbazone was developed for the selective determination of Cr3+ ions.MethodsThe optimum electrode composition contained ionophore, poly (vinyl chloride) (PVC), bis (2‐ethylhexyl) sebacate (BEHS) and potassium tetrakis (p‐chlorophenyl) borate (KTpClPB) in ratios of 4.0: 61.0: 34.0: 1.0 (mg), respectively. Potential measurements were performed using a computer‐controlled multi‐channel potentiometric measurement system.ResultsThe developed Cr (III)‐selective electrode exhibited a low detection limit of 3.96 × 10−6 M over a wide concentration range of 1.0 × 10−5 – 1.0 × 10−1 M (R2: 0.9979). The electrode exhibited good selectivity towards Cr3+ ions among metal ions with different charges. The chromium (III)‐selective electrode, which exhibited highly reproducible results in three different concentration ranges, also had a very fast response time of 5 s.ConclusionsThe developed Cr (III)‐selective electrode were successfully performed in various beverage samples. As a result, the proposed electrode can be an alternative to other analytical methods in the analysis of Cr3+ ions.
DergiPark (Istanbul University), Dec 31, 2021
In this study, a novel all-solid-state contact poly(vinylchloride) (PVC) membrane potassium selec... more In this study, a novel all-solid-state contact poly(vinylchloride) (PVC) membrane potassium selective sensor with a pyrazole derivative molecule as an ionophore has been developed. The potassium selective sensor has a composition of PVC, ionophore, anion excluder (potassium tetrakis (p-chlorophenyl)borat (KTpClPB)) and plasticizer (bis(2ethylhexyl)adipate (DEHA)) in the ratio of 32.0:4.0:1.0:63.0 (mg). The potassium selective sensor works in a linear concentration range of 1.0×10-5 to 1.0×10-1 M with a low detection limit of 6.02 × 10 −6 M The developed potassium selective sensor works in pH range of 6.0-10.0 and has good repeatability, selectivity and a short response time of 10 seconds. Finally, the developed potassium selective sensor was successfully used in the determination of potassium in tap water and a drug sample. Bu çalışmada, pirazol türevi bir molekülünün iyonofor olarak kullanıldığı yeni tümüyle katı hal kontak poli(vinilklorür) (PVC) membran potasyum sensörü geliştirildi. Potasyum seçici sensör PVC, iyonofor, potasyum tetrakis (p-klorofenil)borat (KTpClPB)) ve plastikleştirici (bis (2-etilheksil)adipat (DEHA))'ın 32.0:4.0:1.0:63.0 (mg)'lık bileşimine sahiptir. Geliştirilen potasyum seçici sensör, 6.02×10-6 M'lık düşük algılama limiti ile 1.0×10-5-1.0×10-1 M konsantrasyon aralığında doğrusal olarak çalışmaktadır. Geliştirilen potasyum seçici sensör pH 6.0-10.0 aralığında çalışmaktadır, iyi tekrarlanabilirlik, iyi seçicilik ve 10 saniyelik kısa cevap zamanına sahiptir. Son olarak, geliştirilen potasyum seçici sensör musluk suyu ve ilaç örneğinde potasyum tayininde başarıyla kullanılmıştır.
Social Science Research Network, 2022
International Journal of Environmental Analytical Chemistry, Feb 4, 2021
Ion-selective electrodes or sensors are preferred by researchers in the determination of various ... more Ion-selective electrodes or sensors are preferred by researchers in the determination of various ions since they provide very high selectivity and wide concentration range in environmental, industr...
ChemistrySelect, Jan 18, 2022
A poly(vinyl chloride) (PVC) membrane potentiometric sensor was developed for the determination o... more A poly(vinyl chloride) (PVC) membrane potentiometric sensor was developed for the determination of anti‐epileptic drug levetiracetam. For this purpose, levetiracetam‐tetraphenylborate (LEV‐TPB) ion‐pair was synthesized and the synthesized ion‐pair was used as ionophore in PVC membrane structures. The membrane composed of 3.0 % (w/w) LEV‐TPB ion‐pair, 32.0 % (w/w) PVC, and 65.0 % (w/w) o‐nitrophenyloctylether (o‐NPOE) was determined as the membrane with the best potentiometric properties. The developed sensor exhibited a linear response in the concentration range from 1.0×10−5 to 1.0×10−1 mol L−1 and had a detection limit of 6.31×10−6 mol L−1. For this sensor, pH working range and response time were determined as 6.0–8.0 and ≈25 s, respectively. The sensor displayed a good selectivity for levetiracetam in the presence of a number of common ionic species and some anti‐epileptic drug. The proposed levetiracetam‐selective sensor was successfully applied for the determination of levetiracetam in pharmaceutical drug samples which is used in the treatment of epilepsy.
Organic communications, Sep 19, 2021
Potentiometric methods are a type of electrochemical analysis which are used widely in many appli... more Potentiometric methods are a type of electrochemical analysis which are used widely in many applications due to their multiple advantages such as wide concentration range, low detection limit, high selectivity, and sensitivity. Potentiometric sensors have many advantages over the other analytical methods and have been successfully applied in different real sample analyzes. Crown ethers are a group of macrocyclic compounds and have been used as ionophores by researchers due to their favorable chemical structures. In this review, we provide a description on crown ethers used as ionophores in potentiometric sensors.
Critical Reviews in Analytical Chemistry, Sep 29, 2020
Potentiometry is extensively studied by researchers as one of the electrochemical methods due to ... more Potentiometry is extensively studied by researchers as one of the electrochemical methods due to its multiple advantages. Until today, thousands of potentiometric sensors have been developed and applied successfully in many fields such as medicine, environmental monitoring, agriculture, industry and pharmaceutical sciences. Clinical drug analyses and determination of drugs in biological samples are highly important from a medical point of view. These analyses are carried out using various analytical devices including potentiometric sensors. These potentiometric sensors are superior to other devices in terms of several performance parameters, and thus present a good alternative for researchers. Using potentiometric sensors, very successful results in the identification of drug molecules in body fluids have been obtained and reported in the literature up to now. In this study, we review potentiometry-based sensors developed for the determination of drug molecules in various biological samples such as blood serum and urine, and touch upon their performance features in these applications.
Critical Reviews in Analytical Chemistry, Jan 13, 2020
Potentiometry is one of the most important electrochemical methods and potentiometric based senso... more Potentiometry is one of the most important electrochemical methods and potentiometric based sensors have been extensively studied by researchers for many years. The fact that potentiometric sensors have several advantages over other analytical devices is another reason for intensive research on the topic. In this area, hundreds of different sensors have been developed till today and introduced into the literature. The successful use of the developed sensors, particularly in real sample analysis, has made potentiometric sensors the center of attention. In this review, we highlight the studies which have been successfully applied to the developed drug samples and also to many real samples, with high recovery rates.
Hacettepe University Journal of the Faculty of Pharmacy, Apr 20, 2022
The Use of Valproic Acid in the Treatment of Epilepsy and Determination of Biological Matrices Re... more The Use of Valproic Acid in the Treatment of Epilepsy and Determination of Biological Matrices Review Article ÖZET Epilepsi kronik nörolojik bir hastalıktır ve tedavisi uzun süreli veya ömür boyu sürmektedir. Anti-epileptik ilaçlar epilepsi tedavisinde kullanılan önemli farmakolojik ajanlardır. Epilepsi tedavisinde kullanılmak üzere seçilen anti-epileptik ajan, mümkün olduğunca az yan etkiye sahip olmalı ve nöbet gelişimini engellemelidir. Valproik asit neredeyse tüm epileptik nöbetlerin tedavisinde oldukça etkili olan geniş spektrumlu bir ilaçtır. Güvenilir profili nedeniyle dünya genelinde oldukça yaygın olarak kullanılmaktadır. Tedavi boyunca insan kanındaki valproik asidin terapötik seviyesi izlenmelidir. Bu nedenle, çeşitli analitik yöntemler kullanılarak farklı biyolojik örneklerde valproik asit test prosedürleri önerilmiştir. Bu derlemede, biyolojik örneklerde valproik asidin tayinine yönelik bildirilen analitik metotlar ve bu metotların performans özelliklerine değinilmiştir.
Bulletin of Materials Science, Jun 27, 2022
ChemistrySelect, Sep 1, 2022
In this study, a novel PVC‐based membrane containing (E)‐2‐(1‐(4‐(3‐(4‐chlorophenyl)ureido)phenyl... more In this study, a novel PVC‐based membrane containing (E)‐2‐(1‐(4‐(3‐(4‐chlorophenyl)ureido)phenyl)ethylidene)hydrazine carbothioamide (5) as an electroactive component (ionophore) along with potassium tetrakis (p‐chlorophenyl) borate (KTpClPB) and bis(2‐ethylhexyl)adipate (DEHA) in the ratio 4.0 : 32.0 : 1.0 : 63.0 (ionophore:PVC:KTpClPB:DEHA) (w/w) was used to develop a lead(II)‐selective potentiometric sensor. The sensor exhibited a Nernstian response over a wide concentration range from 1.0×10−5 to 1.0×10−1 mol L−1 with a slope of 28.0±2.0 mV/decade, and a detection limit of 1.65×10−6 mol L−1. It displayed very good selectivity towards Pb(II) ions over other cationic species. The lead(II)‐selective sensor showed a fast response time of 5 s, good repeatability, and it worked in the broad pH range of 5.0–11.0. The sensor could be used as an indicator electrode in the quantification of Pb(II) by potentiometric titration against ethylenediaminetetraacetic acid (EDTA). In addition, this sensor was applied for the direct determination of Pb(II) in different water samples including spring water, purification water, commercial water, waste water and in a waste battery sample.
Journal of Chemical Sciences, Jan 25, 2020
In this study, all-solid-state contact PVC membrane silver(I)-selective sensor has been prepared ... more In this study, all-solid-state contact PVC membrane silver(I)-selective sensor has been prepared and 5,10,15,20-tetra(4-pyridyl)-21H,23H-porphine used as ionophore. Optimum membrane composition; 3.5% ionophore, 59.6% Bis(2-ethylhexyl) sebacate (BEHS), 1.0% potassium tetrakis (p-chlorophenyl) borate (KTpClPB) and 35.9% polyvinyl chloride (PVC). The developed silver(I)-selective sensor exhibited a linear response (E =-51,57 (-log[Ag ? ]) ? 1690,6 and R 2 = 0,9986) in the varying concentration range of 1.0 9 10-1 to 1.0 9 10-5 mol L-1 silver ions. The limit of detection of the sensor was calculated as 1.9 9 10-6 mol L-1. The silver(I)-selective sensor exhibited good selectivity towards some alkali, alkali earth and heavy metal ions. The sensor can be used in the pH range from 4.0 to 10.0. The sensor has been shown to have good reusability and response time less than 8 s. The sensor was used as an indicator electrode in titrations of silver nitrate with sodium chloride solution and was successfully applied for the determination of the different water samples.
Journal of inclusion phenomena and macrocyclic chemistry, Jul 27, 2020
Porphyrins are a group of macrocyclic compounds which are widely used in many applications in the... more Porphyrins are a group of macrocyclic compounds which are widely used in many applications in the literature due to their multiple functions. One of their application areas is in the development of sensors which transform changes in physical and chemical parameters into electrical signals. Novel chemical sensors selective and sensitive for many anions and cations have been fabricated with the advancements in the technology. Real sample applications of these sensors can be successfully performed. In recent years, potentiometric methods have drawn researchers' attention and they have been highly studied because of their superiority over other analytical devices. Ionophores which are used in the development of potentiometric sensors and ion-selective electrodes are the most important components of these systems. Therefore, porphyrin molecules, which have favorable chemical structures, can be directly used as an active component (ionophore) in the structure of potentiometric sensors. In this review, we investigated porphyrin derivatives used as ionophore in the design of potentiometric sensors and we focused on newly developed potentiometric sensors based on porphyrin.
Journal of Hazardous Materials, Jul 31, 2006
Adsorption equilibrium of stearic acid onto natural bentonite with Turkish origin was studied at ... more Adsorption equilibrium of stearic acid onto natural bentonite with Turkish origin was studied at the temperatures of 298, 308 and 318 K. SEM and XRD analysis show that the bentonite used as adsorbent is composed of microcrystal and porous structure. The specific surface area was determined by BET method as 38.6 m 2 /g. The adsorption of stearic acid onto bentonite was conformed to the Langmiur and Freundlich isotherms. The equilibrium parameter, R L revealed that the bentonite is a good adsorbent for stearic acid. The sorption capacity of bentonite studied decreases with increasing temperature. However, it is concluded that the adsorption capacity of bentonite for the stearic acid under the same experimental conditions is in comparable level in terms of that of the rice husk ash given in literature. Thermodynamic parameters, G • ads , was calculated to be between −21.8 and −22.8 kJ mol −1. H • ads and S • ads were found to be −9.2 kJ mol −1 and 42.4 J mol −1 K −1 , respectively. These parameters obtained as a function of temperature indicate that the adsorption of stearic acid onto bentonite was a spontaneous and an exothermic process. An FT-IR study on the adsorbed material was used to verify the interaction of the stearic molecule with bentonite after adsorption process.
Journal of the Indian Chemical Society, May 1, 2022
Journal of Analytical Chemistry, Dec 1, 2009
... 11. Buck, CF, Mayewski, PA, Spencer, MJ, Whitlow, S., Twickler, MS, and Barrett, D., J. Chrom... more ... 11. Buck, CF, Mayewski, PA, Spencer, MJ, Whitlow, S., Twickler, MS, and Barrett, D., J. Chromatogr. A, 1992, vol. 594, p. 225. 12. Isildak, I. and Covington, AK, Electroanal., 1993, vol. 5, p. 815. 13. Hong, US, Kwon, HK, Nam, H., Cha, GS, Kwon, KH, and Peang, KJ, Anal. Chim. ...
International journal of chemistry and technology, Dec 28, 2018
This work deals with the development of micro-size potentiometric calcium-selective electrode. A ... more This work deals with the development of micro-size potentiometric calcium-selective electrode. A simple and rapid potentiometric method of determining calcium concentration, based on 10,19-Bis[(octadecylcarbamoyl) methoxyacetyl]-1,4,7,13,16-pentaoxa-10,19-diazacycloheneicosane, is described. For this aim, calcium-selective polyvinylchloride (PVC) membrane was prepared by coating on the surface of solid-contact. Calcium-selective PVC membrane electrode does not contain internal reference electrode and solution. The potentiometric performance of calcium-selective PVC membrane electrode (selectivity constant, liner working range, detection limit, response time, pH working range, repeatability, lifetime, and time dependent potential decay) was determined using computer controlled measurement system in static conditions. The results showed that the calcium-selective electrode exhibited good reproducibility in calcium determination.
Journal of The Chinese Chemical Society, Jun 7, 2022
A novel poly(vinyl chloride; PVC) membrane‐based Cu(II)–selective sensor has been developed using... more A novel poly(vinyl chloride; PVC) membrane‐based Cu(II)–selective sensor has been developed using synthesized 5,10,15,20‐tetrakis(4‐methoxycarbonylphenyl)porphyrin as an ionophore. The Cu(II)–selective sensor exhibits a Nernstian response for Cu(II) ion over a wide concentration range of 1.0 × 10−5 to 1.0 × 10−1 mol L−1 with the slope of 27.0 ± 2.5 mV/decade, and a lower limit of detection of 1.88 × 10−6 mol L−1. The novel sensor shows good repeatability and high selectivity for Cu(II) ions over other mono‐, bi‐ and trivalent cations. The sensor potential response remains unaffected by pH in the range of 4.4–10.6 and exhibits a fast response time of less than 10s. Finally the developed Cu(II)–selective sensor has been successfully used as an indicator electrode in the potentiometric titration of Cu2+ against ethylenediaminetetraacetic acid and also in the determination of Cu(II) ion concentration in different water and beverage samples.
Chemical Papers, Jul 17, 2023