Using MoS2/Fe3O4 as Ion-Electron Transduction Layer to Manufacture All-Solid-State Ion-Selective Electrode for Determination of Serum Potassium

As an essential electrolyte for the human body, the potassium ion (K+) plays many physiological roles in living cells, so the rapid and accurate determination of serum K+ is of great significance. In this work, we developed a solid-contact ion-selective electrode (SC-ISE) using MoS2/Fe3O4 composites as the ion-to-electron transducer to determine serum K+. The potential response measurement of MoS2/Fe3O4/K+-ISE shows a Nernst response by a slope of 55.2 ± 0.1 mV/decade and a low detection limit of 6.3 × 10−6 M. The proposed electrode exhibits outstanding resistance to the interference of O2, CO2, light, and water layer formation. Remarkably, it also presents a high performance in potential reproducibility and long-term stability.

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Determination of Iodide in Nutritional Beverage Products Using an Ion Selective Electrode

Journal of AOAC INTERNATIONAL ◽

10.1093/jaoac/61.6.1366 ◽

1978 ◽

Vol 61 (6) ◽

pp. 1366-1369 ◽

Cited By ~ 1

Author(s):

Preston Miles

Keyword(s):

Neutron Activation Analysis ◽

Standard Deviation ◽

Accurate Determination ◽

Ion Selective Electrode ◽

Selective Electrode ◽

Relative Standard ◽

Dry Ashing ◽

Nutritional Beverage ◽

Ppm Level

Abstract An ion selective electrode procedure is described for the precise, accurate determination of iodide at the sub-ppm level in a variety of nutritional beverages. The relative standard deviation of the analysis is 1-4%; recoveries range from 90 to 120%. Comparison with results from neutron activation analysis and the traditional Sandell-Kolthoff procedure shows that the ion selective electrode procedure is free of determinant error and that dry ashing of samples can lead to low results.

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Positive interference in lithium determinations from clot activator in collection container

Clinical Chemistry ◽

10.1093/clinchem/43.4.675 ◽

1997 ◽

Vol 43 (4) ◽

pp. 675-679 ◽

Cited By ~ 13

Author(s):

Maureen Sampson ◽

Mark Ruddel ◽

Suzanne Albright ◽

Ronald J Elin

Keyword(s):

Ion Selective Electrode ◽

Selective Electrode ◽

Becton Dickinson ◽

Silicone Surfactant ◽

Intermittent Exposure ◽

Li Ion ◽

Clot Activator ◽

Positive Interference

Abstract We describe positive interference with the ion-selective electrode determination of lithium (Lytening 2Z analyzer; Dade) when blood is collected in a 10-mL plain red-top plastic Vacutainer Plus Tube® (Becton Dickinson) containing a silica clot activator and silicone surfactant (prod. no. 36–7820). We evaluated both the original tube (blue-labeled) and a new tube formulated to contain less silicone surfactant (striped-labeled). We determined that the interference is from either the silica clot activator or the silicone surfactant used to fix the silica to the tube and is inversely related to the volume of blood in the tube. Long-term intermittent exposure of the Li ion-selective electrode to the silica clot activator or surfactant results in decreased Li values—in terms of both the positive interference by the silica clot activator or surfactant and the actual Li determinations. Moreover, this long-term interference with the Li ion-selective electrode for patients’ specimens is undetected by the Dade control material (QCLytes).

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Titration of sulphates and lead using lead ion selective electrode

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19810368 ◽

1981 ◽

Vol 46 (2) ◽

pp. 368-376 ◽

Cited By ~ 4

Author(s):

Josef Veselý

Keyword(s):

Ionic Strength ◽

Electrode Surface ◽

Salt Content ◽

Ion Selective Electrode ◽

Lead Ion ◽

Selective Electrode ◽

Limit Of Determination ◽

Total Salt Content ◽

Automatic Titration

Titration of sulphates with lead perchlorate employing lead ion selective electrode indication was studied using additions of various organic solvents at different pH' and ionic strength values. As the optimum emerged systems with 60-70% 1,4-dioxane, pH' 5.3-5.6. After dehydration with sodium hydroxide, dioxane must be freed from the electrode surface-oxidizing impurities by their reduction with sodium metal and subsequent distillation. The method was applied to determination of sulphates in mountain spring waters. Units of ppm can be determined; the limit of determination, however, depends considerably on the content of dioxane, total salt content in the sample, and speed of the semi-automatic titration. Lead can be determined with EDTA in concentrations down to c(Pb2+) = 5 . 10-6 mol l-1.

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Selective determination of thiamine (vitamin B1) in pharmaceutical preparations by direct potentiometric argentometric titration with use of the silver—silver sulphide ion-selective electrode

Talanta ◽

10.1016/0039-9140(89)80184-5 ◽

1989 ◽

Vol 36 (10) ◽

pp. 1011-1015 ◽

Cited By ~ 15

Author(s):

Saad S.M. Hassan ◽

Eman Elnemma

Keyword(s):

Vitamin B1 ◽

Pharmaceutical Preparations ◽

Ion Selective Electrode ◽

Selective Electrode ◽

Selective Determination ◽

Silver Sulphide ◽

Silver Silver

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Iodide Ion-Selective Electrode and Its Application to the Determination of Organic Compounds

Journal of the Chinese Chemical Society ◽

10.1002/jccs.198200027 ◽

1982 ◽

Vol 29 (3) ◽

pp. 163-167 ◽

Cited By ~ 4

Author(s):

Fu-Chung Chang ◽

Wen-Lin Chang

Keyword(s):

Organic Compounds ◽

Ion Selective Electrode ◽

Selective Electrode ◽

Iodide Ion

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Visualizing the Bohr effect in hemoglobin: neutron structure of equine cyanomethemoglobin in the R state and comparison with human deoxyhemoglobin in the T state

Acta Crystallographica Section D Structural Biology ◽

10.1107/s2059798316009049 ◽

2016 ◽

Vol 72 (7) ◽

pp. 892-903 ◽

Cited By ~ 5

Author(s):

Steven Dajnowicz ◽

Sean Seaver ◽

B. Leif Hanson ◽

S. Zoë Fisher ◽

Paul Langan ◽

...

Keyword(s):

Structural Changes ◽

Accurate Determination ◽

Bohr Effect ◽

Salt Bridges ◽

Histidine Residues ◽

Regions Of Stability ◽

The Individual ◽

T State

Neutron crystallography provides direct visual evidence of the atomic positions of deuterium-exchanged H atoms, enabling the accurate determination of the protonation/deuteration state of hydrated biomolecules. Comparison of two neutron structures of hemoglobins, human deoxyhemoglobin (T state) and equine cyanomethemoglobin (R state), offers a direct observation of histidine residues that are likely to contribute to the Bohr effect. Previous studies have shown that the T-state N-terminal and C-terminal salt bridges appear to have a partial instead of a primary overall contribution. Four conserved histidine residues [αHis72(EF1), αHis103(G10), αHis89(FG1), αHis112(G19) and βHis97(FG4)] can become protonated/deuterated from the R to the T state, while two histidine residues [αHis20(B1) and βHis117(G19)] can lose a proton/deuteron. αHis103(G10), located in the α1:β1dimer interface, appears to be a Bohr group that undergoes structural changes: in the R state it is singly protonated/deuterated and hydrogen-bonded through a water network to βAsn108(G10) and in the T state it is doubly protonated/deuterated with the network uncoupled. The very long-term H/D exchange of the amide protons identifies regions that are accessible to exchange as well as regions that are impermeable to exchange. The liganded relaxed state (R state) has comparable levels of exchange (17.1% non-exchanged) compared with the deoxy tense state (T state; 11.8% non-exchanged). Interestingly, the regions of non-exchanged protons shift from the tetramer interfaces in the T-state interface (α1:β2and α2:β1) to the cores of the individual monomers and to the dimer interfaces (α1:β1and α2:β2) in the R state. The comparison of regions of stability in the two states allows a visualization of the conservation of fold energy necessary for ligand binding and release.

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