Titration of sulphates and lead using lead ion selective electrode

1981 ◽  
Vol 46 (2) ◽  
pp. 368-376 ◽  
Author(s):  
Josef Veselý

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.

2015 ◽  
Vol 12 (1) ◽  
pp. 188-196
Author(s):  
Baghdad Science Journal

A new method for construction ion-selective electrode (ISE) by heating reaction of methyl orange with ammonium reineckate using PVC as plasticizer for determination methyl orange and determination Amitriptyline Hydrochloried drug by formation ion-pair on electrode surface . The characteristics of the electrode and it response as following : internal solution 10-4M , pH (2.5-5) ,temperature (20-30) and response time 2 sec. Calibration response for methyl orange over the concentrationrange 10-3 -10-9 M with R=0.9989 , RSD%=0.1052, D.O.L=0.315X10-9 MEre%=(-0.877- -2.76) , Rec%.=(97.230 -101.711) .


1979 ◽  
Vol 62 (2) ◽  
pp. 315-319
Author(s):  
Saad S M Hassan ◽  
Mohamed T Zaki ◽  
Mohamed H Eldesouki

Abstract Simple, rapid, and accurate methods have been developed for determining vitamin Bx in pharmaceutical preparations without prior separation of the vitamin. The methods are based on the desulfurization reaction with potassium plumbite and measurement of the unreacted lead (II) ions at 217 nm using atomic absorption spectroscopy (AAS), or by titration with EDTA at pH 4.5 with the lead ion selective electrode and Gran's plot. The results compare favorably with those obtained using the USP fluorometric method. Recoveries of pure vitamin Bx averaged 99.1%, with a standard deviation of 0.8%, and 99.0%, with a standard deviation of 0.7%, for the AAS and ion selective electrode procedures, respectively.


1971 ◽  
Vol 54 (4) ◽  
pp. 760-763
Author(s):  
William L Hoover ◽  
James R Melton ◽  
Peggy A Howard

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.


1990 ◽  
Vol 70 (3) ◽  
pp. 411-424 ◽  
Author(s):  
F. L. WANG ◽  
P. M. HUANG

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


2007 ◽  
Vol 4 (2) ◽  
pp. 90 ◽  
Author(s):  
Julien Rachou ◽  
Christian Gagnon ◽  
Sébastien Sauvé

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.


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