Ion selective electrodes, potentiometry, and potentiometric titrations

Buck, Richard P.

doi:10.1021/ac60313a011

Cited by 92 publications

(32 citation statements)

References 824 publications

(145 reference statements)

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“…Although the electrode does not display a full Nernstian behavior, it is stated in the literature that the electrodes with these slope values can conveniently be employed in analytical studies. [40][41][42] Also, those electrodes giving a slope value of 55 mV or more at 25˚C are accepted to be Nernstian in the literature. The reason why the calibration curve deviates from the linearity in regions lower than pH 2 and higher than pH 12 can be explained as follows.…”

Section: Working Range and Slope Of The Electrodementioning

confidence: 99%

Hydrogen Ion-Selective Poly(vinyl chloride) Membrane Electrode Based on a Calix[4]arene

et al. 2003

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IntroductionFor more than 60 years, pH-glass electrodes have been widely used, and pH measurements in various samples are still made using these electrodes. They are very popular due to their high selectivity and dynamic pH range. However, in spite of the distinctive potential characteristic of pH-glass electrodes and their use in routine pH measurements for so many years, they have certain limitations, such as high resistance, brittleness, instability in hydrofluoric acid and fluoride-containing media. They also create problems in the construction of microelectrodes for biological applications and in vivo measurements. That is why studies related to the construction of nonglass pH electrodes have been gaining momentum. The construction of PVC pH electrodes based on neutral carriers will solve most of these problems. The facts that PVC electrodes have low electrical resistance and that they are easy to construct have increased interest in the implementation of these electrodes in place of glass membranes. These electrodes are of great practical importance, since they are solid and unbreakable. For example, there have been numerous studies about the use of pH-sensitive liquid membrane electrodes in clinical studies. 1 Le Blanc et al. prepared a liquid-membrane electrode with p-octadecyloxy-m-chlorophenylhydrazonemesoxalonitrile (OCPH) as a proton carrier. 2 Simon et al. developed different PVC membrane pH electrodes based upon tri-n-dodecylamine, which gave good response characteristics. [3][4][5][6][7][8] Wu and Yu prepared a pH-sensitive electrode using methyldioctadecylamine (MDODA) as a neutral carrier.9 Later, some authors continued similar research, and other compounds have been investigated as ionophores for hydrogen ions, many of which can be used for a very wide range of pH values. [10][11][12][13][14][15][16][17][18][19][20][21][22][23] Calixarenes are metacylclophanes comprising phenolic and methylene units. They are very popular as attractive and excellent ionophores because they provide a platform for the attachment of convergent binding groups to create host molecules, mainly for the attraction of simple cations, anions and small molecules. [24][25][26][27][28][29][30][31] McKervey et al. first recognized that calixarenes with cations-complexing groups attached to the lower rim may possess the molecular requirements for the type of ionophore used in ion-selective electrodes (ISEs). 32,33 For example, the tetraesters of calix[4]arenes have been proved to be excellent ionophores for sodium in liquid membrane and PVC membrane electrodes. These types of electrodes based on such compounds were shown to be capable of measuring sodium in blood. 34,35 Some calixarenetetraesters are now commonly used in commercial blood electrolyte analyzers for sodium determination. The purpose of this study was to develop a hydrogen ionselective electrode using a macrocyclic compound of calix[4]arene as a neutral carrier and to determine its lifetime, response time, optimum working range and other response characteristics....

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Section: Working Range and Slope Of The Electrodementioning

confidence: 99%

Hydrogen Ion-Selective Poly(vinyl chloride) Membrane Electrode Based on a Calix[4]arene

et al. 2003

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“…In practice, slopes of between 55 and 59 mV decade -1 are referred to as Nernstian for analytical purposes. 30 This range was found to be in compatible with a commercial electrode. The limit of detection, as determined from the intersection of two extrapolated segments of the calibration graph, was 3.1 × 10 -7 M. 31 …”

Section: Influence Of Membrane Compositionmentioning

confidence: 68%

Thiocyanate Ion-selective PVC Membrane Electrode Based on N,N′-Ethylene-bis(4-methylsalicylidineiminato)nickel(II)

et al. 2006

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Experimental ReagentsReagent-grade high relative molecular weight PVC, trioctylmethyl ammonium chloride (TOMAC) and dioctyl phthalate (DOP) were used as received from Aldrich. Potassium or sodium salts of all anions, tetrahydrofuran (THF); all other chemicals were of highest purity available from Merck, and were used without further purification, except for THF, N′-ethylene-bis(4-methylsalicylidineiminato)nickel(II) [Ni(EBMSI)] complex as a carrier for a thiocyanate-selective electrode is reported. The influences of the membrane composition, pH and possible interfering anions were investigated based on the response properties of the electrode. The electrode exhibited a good Nernstian slope of -58.9 ± 0.7 mV decade -1 , over a wide pH range of 3.5 -8.5 and a linear range of 1.0 × 10 -6 -1.0 × 10 -1 M for thiocyanate. The detection limit of electrode was 3.1 × 10 -7 M SCN -. The selectivity coefficients determined by a fixed interference method (FIM) indicate that a good discriminating ability towards the SCN -ion compared to other anions. The proposed sensor had a fast response time of about 5 -15 s and could be used for at least 3 months without any considerable divergence in the potential. It was applied as an indicator electrode in the titration of thiocyanate with Ag + and in the potentiometric determination of thiocyanate in saliva and urine samples.

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“…It is well understood that, the sensitivity and selectivity of the ion-selective electrodes depend not only on the nature of the ion carrier used, but also significantly on the membrane composition and the properties of solvent mediators and additives used [31][32][33][34][35][36] . Thus, the influences of the membrane composition, nature of solvent mediator and additive on the response characteristics of the SCN − sensor were investigated, and the results are shown in Table 1.…”

Section: Influence Of Membrane Compositionmentioning

confidence: 99%

Highly Thiocyanate‐Selective Membrane Electrode Based on the Bis(Benzoylacetone) propylenediimine Copper(II)Complex

et al. 2007

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A potentiometric thiocyanate-selective sensor based on copper(II) bis(benzoylacetone)propylenediimine complex as a new neutral carrier for a thiocyanate-selective electrode is reported. The response mechanism is discussed in view of the UV spectroscopy technique. The sensor displays a near Nernestian slope of -57.4 ± 0.5 mV per decade. The working concentration range of the electrode is 8.0×10 -7 -1.0×10 -1 M with a detection limit of 7.4×10 -7 M. The response time of the sensor in the all concentration ranges is very short (5-10 s). The response of the sensor is independent of pH, in the pH range of 1.7-11.5. The best performance was obtained with a membrane composition of 32.69% PVC, 57.34% dibutyl phthalate, 6.82% complex and 3.15% methyltrioctylammonium chloride (MTOAC) as additive. The proposed electrode is more selective than other proposed methods for determination of thiocyanate ion over a wide variety of common inorganic and organic anions and it was successfully applied to direct determination of thiocyanate in the presence of other anions in biological, water and waste water samples.

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Ion selective electrodes, potentiometry, and potentiometric titrations

Cited by 92 publications

References 824 publications

Hydrogen Ion-Selective Poly(vinyl chloride) Membrane Electrode Based on a Calix[4]arene

Hydrogen Ion-Selective Poly(vinyl chloride) Membrane Electrode Based on a Calix[4]arene

Thiocyanate Ion-selective PVC Membrane Electrode Based on N,N′-Ethylene-bis(4-methylsalicylidineiminato)nickel(II)

Highly Thiocyanate‐Selective Membrane Electrode Based on the Bis(Benzoylacetone) propylenediimine Copper(II)Complex

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