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.

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.

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.

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

Chemosensors ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 155
Author(s):  
Yan Su ◽  
Ting Liu ◽  
Caiqiao Song ◽  
Aiqiao Fan ◽  
Nan Zhu ◽  
...  
Keyword(s):  
High Performance ◽  
Accurate Determination ◽  
Water Layer ◽  
Ion Selective Electrode ◽  
Potential Response ◽  
Selective Electrode ◽  
Response Measurement ◽  
Long Term Stability

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.

Automated Fluoride Ion Determination

1977 ◽  
Vol 14 (1-6) ◽  
pp. 269-274 ◽  
Author(s):  
David C. Cowell
Keyword(s):  
Continuous Flow ◽  
Ion Concentration ◽  
Fluoride Ion ◽  
Selective Electrode ◽  
Automated Method ◽  
Electrode Response ◽  
Kinetics Of ◽  
Fluoride Ion Selective Electrode ◽  
Flow Techniques

An automated method is described, using standard continuous flow techniques, for the determination of urine fluoride ion concentration using a fluoride ion selective electrode. It is shown that the kinetics of the electrode response to changes in fluoride ion can be used for the accurate measurement of fluoride ion concentration in urine, and that equilibration of the electrode response is not a prerequisite for the measurement of fluoride ion. Recovery experiments are in the range 83 to 90%; in-batch precision is between 0·9 and 1·6% and carryover 2·5% or less.

Determination of urea in 10-?l blood serum samples with a urease reactor / ion-selective electrode cell

1983 ◽  
Vol 81 (1-2) ◽  
pp. 135-147 ◽  
Author(s):  
U. Thanei-Wyss ◽  
W. E. Morf ◽  
P. Lienemann ◽  
Z. Stefanac ◽  
I. Mostert ◽  
...  
Keyword(s):  
Blood Serum ◽  
Ion Selective Electrode ◽  
Selective Electrode ◽  
Serum Samples ◽  
Electrode Cell
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