Determination of Iodide in Feeds and Plants by Ion-Selective Electrode Analysis

1971 ◽  
Vol 54 (4) ◽  
pp. 760-763
Author(s):  
William L Hoover ◽  
James R Melton ◽  
Peggy A Howard
Keyword(s):  
Ionic Strength ◽  
Solid State ◽  
Necessary Conditions ◽  
Ion Selective Electrode ◽  
Phosphate Solution ◽  
Selective Electrode ◽  
Aoac Method ◽  
Low Levels ◽  
High Concentrations

Abstract A method for determining low levels of iodide in feeds and plants is proposed. The samples are mixed with a 10% phosphate solution to maintain relatively constant ionic strength and pH and analyzed with a solid-state iodide electrode. Ashing is not required and there are no significant interferences by ions commonly found in feeds. The method is accurate in determining iodide content ranging from 10.0 ppm to high concentrations. Necessary conditions for storing and cleaning the electrodes are described. The proposed method is rapid and results compare favorably with AOAC method 7.091.

Titration of sulphates and lead using lead ion selective electrode

1981 ◽  
Vol 46 (2) ◽  
pp. 368-376 ◽  
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.

scholarly journals Application of Sparging to the Automated Ion Selective Electrode Determination of Kjeldahl Nitrogen

1980 ◽  
Vol 63 (4) ◽  
pp. 931-936
Author(s):  
Ram B Roy ◽  
John Jansen ◽  
Michael Sahn
Keyword(s):  
Ion Selective Electrode ◽  
Selective Electrode ◽  
Ammonia Sensing ◽  
Automated Method ◽  
Significant Difference ◽  
Naoh Solution ◽  
Kjeldahl Digestion ◽  
Aoac Method ◽  
Kjeldahl Nitrogen

Abstract An automated method has been developed for the determination of total Kjeldahl nitrogen. Sample digests are mixed with a NaOH solution and allowed to make contact with air flowing at 1000 mL/min. The mixture enters the inlet of a heating bath maintained at 75°C. On exit, ammonia gas separates from a sparging vessel and is trapped as ammonium sulfate in a dilute H2SO4 solution. An aliquot of the acid solution is resampled and made alkaline to generate ammonia, which is measured by an ammonia sensing probe. A comparison of this procedure with AOAC method 7.025 shows that the procedure is accurate and that there is no statistically significant difference between them. This procedure introduces a new approach to eliminate the interfering species present in sample digests after Kjeldahl digestion for automated ion selective electrode measurements of ammonia. Thirty samples/h can be analyzed by this method.

Collaborative Study of Ion Selective Electrode Method for the Direct Determination of Fluoride in Feeds

1975 ◽  
Vol 58 (3) ◽  
pp. 477-481 ◽  
Author(s):  
Laszlo Torma
Keyword(s):  
Standard Deviation ◽  
Collaborative Study ◽  
Direct Determination ◽  
Ion Selective Electrode ◽  
Official Method ◽  
Selective Electrode ◽  
Standard Curve ◽  
Electrode Method ◽  
Aoac Method

Abstract A rapid and precise method for the determination of fluoride in feeds employs HC1 extraction of the sample. Acetate buffer and sodium citrate are added to control pH and ionic strength. The amount of fluoride is calculated from a standard curve after measuring the potentials of standard and sample solutions. Eight collaborators participated in the study of the method. Statistical values on 3 pairs of samples were calculated. The standard deviation, precision, coefficient of variation, and bias, respectively, were: Pair 1, 0.005071, 0.001763, 3.09, 0.0034; Pair 2, 0.037122, 0.006475, 1.82, 0.0258; Pair 3, 0.034587, 0.013021, 2.63, 0.0227. The results from the proposed method agreed favorably with the values obtained by using the official final action AOAC method, 7.089. The average and standard deviation, respectively, for individual samples by the proposed method were: Sample 3, 0.049, 0.0029; Sample 4, 0.059, 0.0021; Sample 5, 0.334, 0.0114; Sample 6, 0.341, 0.0101; Sample 7, 0.511, 0.0219; Sample 8, 0.492, 0.0237. By the official method the values were: Sample 3, 0.049, 0.0041; Sample 4, 0.058, 0.0029; Sample 5, 0.334, 0.0055; Sample 6, 0.331, 0.0082; Sample 7, 0.517, 0.0183; Sample 8, 0.499, 0.0175. The ion selective electrode method has been adopted as official first action.

Selective Determination of Nicorandil with a Single Planar Solid‐State Potentiometric Ion Selective Electrode

2021 ◽  
Author(s):  
Emad Hussien ◽  
maha hegazy ◽  
Laila Abdel Fattah ◽  
Hisham Abdellatef ◽  
Mai Abd El-Aziz ◽  
...  
Keyword(s):  
Solid State ◽  
Ion Selective Electrode ◽  
Selective Electrode ◽  
Selective Determination

ION-SELECTIVE ELECTRODE DETERMINATION OF SOLUTION K IN SOIL SUSPENSIONS AND ITS SIGNIFICANCE IN KINETIC STUDIES

1990 ◽  
Vol 70 (3) ◽  
pp. 411-424 ◽  
Author(s):  
F. L. WANG ◽  
P. M. HUANG
Keyword(s):  
Ionic Strength ◽  
Response Time ◽  
Soil Particle ◽  
Ion Selective Electrode ◽  
Pvc Membrane ◽  
Calibration System ◽  
Selective Electrode ◽  
Soil Particles ◽  
K Concentration

The feasibility of using a K ion-selective electrode (K-ISE) to monitor changes in solution K concentration in soil suspensions with time, under shaking conditions, was investigated and its significance in kinetics studies of K adsorption was discussed. Factors that affect the efficiency of the K-ISE method include the response time of the electrode, influence of suspended soil particles, shaking speed, and ionic strength of the system. The response time of the K-ISE decreased with increasing K concentration. Moreover, for a system with a solution K concentration greater than 10 mg K L−1, errors resulting from response delays were negligible when, under shaking conditions, observation time intervals were greater than 30 s. The influence of suspended soil particles on the K-ISE method was negligible for soil suspensions with a solution/soil ratio of 50:1 (vol/wt). Shaking significantly influenced K-ISE determination of solution K concentration. The degree of the influence of shaking on the determination of solution K appeared to be related to ionic factors of the systems. Shaking had much less influence on the soil suspensions, the filtrates and mixed CaCl2-KCl solutions than on pure KCl solutions. Satisfactory results were obtained by taking into account the response time, suspended soil particle and shaking speed factors and by adjusting the ionic strength of the calibration system (KCl standard solution series). Key words: Potassium ion-selective PVC membrane electrode, batch technique, kinetics, calibration system, electrode response time, suspended soil particle, shaking speed, ionic strength

scholarly journals Use of an ion-selective electrode for free copper measurements in low salinity and low ionic strength matrices

2007 ◽  
Vol 4 (2) ◽  
pp. 90 ◽  
Author(s):  
Julien Rachou ◽  
Christian Gagnon ◽  
Sébastien Sauvé
Keyword(s):  
Ionic Strength ◽  
Ion Selective Electrode ◽  
Metal Species ◽  
Analytical Determination ◽  
Operational Parameters ◽  
Selective Electrode ◽  
Time Saving ◽  
Low Salinity ◽  
Low Ionic Strength

Environmental context. The toxicity of metals in the environment is controlled by several parameters including total metal concentration, pH and organic and inorganic ligands (type and concentration). The characterisation of different metal pools in natural matrices (e.g. seawater, soil) is important for the evaluation of their toxic impact. The copper ion-selective electrode (Cu-ISE) is a method of choice for the analytical determination of the speciation (i.e. chemical forms) of divalent copper in natural matrices. This paper clarifies several operational parameters in the hope of decreasing variability of results and increasing the application domain of the Cu-ISE. Abstract. The determination of free copper concentrations in natural matrices is critical for the evaluation of copper toxicity. The ISE is one of the few analytical means for determining the direct speciation of free metal species. We have refined the method for low salinity and low ionic strength solutions for application with soil water extracts or fresh waters. Moreover, we have detailed and standardised a method for using a Cu-ISE with an autotitrator. The standardisation shows a good response and allows significant time saving (under 2 h for the calibration). The results obtained using the ISE are compared with those predicted in the presence of different organic ligands or even the lower free Cu2+ activities resulting from the formation of Cu hydroxyl species. The method was validated for the determination of Cu speciation at environmentally relevant free Cu2+ activity, i.e. ranging between 10−14 to 10−4 M. The chemical equilibrium calculations were made using the MINEQL+ software and the results agree well for pH values between 3 and 10. In terms of precision, the standard deviations of the measured values never exceed 0.1 units, and in terms of accuracy, the measured values were very close to the nominal values, within a range of 0.1. Outside the optimal pH range, the electrode yields higher activity than expected.

Known Addition Procedure for Determining Fluoride in Feeds with an Ion-Specific Electrode

1974 ◽  
Vol 57 (3) ◽  
pp. 508-510 ◽  
Author(s):  
James R Melton ◽  
William L Hoover ◽  
Jo Lynn Ayers
Keyword(s):  
Ionic Strength ◽  
Solid State ◽  
Hydrochloric Acid ◽  
Addition Method ◽  
Citrate Buffer ◽  
Aoac Method ◽  
Low Levels ◽  
Fluoride Electrode ◽  
Feed Samples

Abstract A know addition method for determining low levels of fluoride in feeds with a solid-state fluoride electrode is described. The feed samples are reacted with hydrochloric acid, and a concentrated citrate buffer is added to maintain ionic strength and pH. The amount of fluoride in the sample is calculated from the change in potential after the addition of fluoride standard. Any interferences by ions commonly found in feeds are minimized by the known addition technique. The described method is rapid and precise, and results compare favorably with those from the AOAC method for fluoride, 25.029-25.035.

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