Flow injection analysis: potentiometric

It is seen by examination of Table 1.11(b) that a wide variety of techniques have been employed including spectrophotometry (four determinants), combustion and wet digestion methods and inductively coupled plasma atomic emission spectrometry (three determinants each), atomic absorption spectrometry, potentiometric methods, molecular absorption spectrometry and gas chromatography (two determinants each), and flow-injection analysis and neutron activation analysis (one determinant each). Between them these techniques are capable of determining boron, halogens, total and particulate carbon, nitrogen, phosphorus, sulphur, silicon, selenium, arsenic antimony and bismuth in soils. 

Ohura H, Imato T, Yamasaki S. 1999. Simultaneous potentiometric determination of C103"C102 and C103 HCIO by flow injection analysis using Fe(III)-Fe(II) potential buffer. Talanta 49 1003-1015. 

Potentiometric electrodes of all types In flow-injection analysis (FIA) glass, ion-selective, amperometric electrodes, etc., can all theoretically be used in a detector cell to quantify some chemical substance. 

E. H. Hansen, Flow Injection Analysis New Analytical Methods Based on the Use of Potentiometric and Spectrophotometric Flow-Through Detectors. Anal. Proc., 18 (1981) 261. 

T. E. Hu, Potentiometric Stripping as a Detector for Flow Injection Analysis of Metal Ions. Diss. Abstr. Int. B, 42 (1981) 1874. 

K. Kina, Potentiometric Determinations by Means of Flow Injection Analysis [in Japanese]. Dojin, 25 (1982) 7. 

G. B. Marshall and D. Midgley, Potentiometric Determination of Sulphite by Use of Mercury(I) Chloride-Mercury(II) Sulphide Electrodes in Flow Injection Analysis and in Air-Gap Electrodes. Analyst, 108 (1983) 701. 

H. A. Mottola, C.-M. Wolff, A. lob, and R. Gnanasekaran, Potentiometric and Amperometric Detection in Flow Injection Analysis. In Modern Trends in Analytical Chemistry (Proc. of Two Scientific Symps., Mdtrafured, Hungary, 1982. I. Electrochemical Detection in Flow Analysis ) (E. Pungor, I. Bizas and G. E. Veress, Eds.). Anal. Chem. Symp. Series, 18 (1984) 49. 

J. F. Coetzee and C. Gunaratna, Potentiometric Gas Sensor for the Determination of Free Chlorine in Static or Flow Injection Analysis Systems. Anal. Chem., 58 (1986) 650. 

H. Ohura, T. Imato, S. Yamasaki, and N. Ishibashi, Potentiometric Flow Injection Analysis of Trace Bromate Based on Its Redox-Reaction with the... 

D. E. Davey, D. E. Mulcahy, and G. R. O Connell, Rapid Determination of Fluoride in Potable Waters by Potentiometric Flow Injection Analysis. Anal. Lett., 19 (1986) 1387. 

Potentiometry is the most common method of electrochemical detection used in flow injection analysis. This methodology creates more favorable conditions for potentiometric measurements when compared to batch procedures. In FIA measurements, it is easier to avoid incidental contamination or that resulting from leakage of the solution from the reference electrode. Moreover, deactivation of the sensing surface of the indicator electrode due to adsorption, precipitation, or corrosion is minimized greatly as a consequence of the short contact time with the sample... 

The common spectrophotometric method for creatinine detection is based on the Jaffe reaction between creatinine and picric acid in alkaline solution to form a red-yellow complex. However, substances of endogenous and exogenous origin usually cause interference. In spite of these problems, the colorimetric method of Jaffe is still used today for the determination of creatinine in biological samples.A batchwise kinetic procedure and flow injection analysis have shown the possibility to determine creatinine in human urine samples by this reaction, free from any systematic error.Enzymatic methods have been reported to increase specificity/selectivity but still suffer from interferences. To avoid these problems, new analytical methods were developed. Several electtoanalytical techniques, based on potentiometric or amperometric detection, are available. Potentiometric methods using several sensors and biosensors were known for the... 

Voltammetry [71], electrophoresis [67], and potentiometric stripping analysis have been proposed. The latter method associated with flow injection analysis allows very fast determinations but the problems related to desensitizing of the electrodes by the proteins are not completely resolved [82]. 

A.S. Tauliq, AM.S. Abulkibash, Differential electrolytic potentiometric detector in flow injection analysis for cyanide determination, J. Flow Injection Anal. 24 (2007) 9 12. 

S.S.M. Hassan, H.E.M. Sayom, S.S. Al-Mehrezi, A novel planar miniaturized potentiometric sensor for flow injection analysis of nitrates in wastewaters, fertilizers and pharmaceuticals. Anal. Chim. Acta 581 (2007) 13-18. 

A new salicylate eledrode based on polymer membranes was used in a flow injection analysis system [66]. The electrode membrane contains 29.2-31.0% of PVC, 5.8-6.3% of tetraoctylammonium salicylate, 58.5-62.7% of o-nitrophenyloctylether and 6.5% of p-ferf-octylphenol. The tubular electrode was stored for approx. 6 months in a sodium salicylate solution. The electrode shows the slope of response curve close to theoretical — 56.0 0.6 mV decade in the range of 5 x 10" -10" mol L the response time is up to 5 s. The electrode can be used in a pH range of 6-9. The log K selectivity coefficients are 2-2.9 for acetates, 1.8-2.2 for chlorates, 0.7-1.0 for nitrates and 0.6-1.3 for acetosalicylates. The tubular salicylate electrode can be used for determination of acetylsalicylic add, after its previous analysis to salicylate, in multicomponent preparations and effervescent tablets (Anadin Extra, Aspirin, Dolviran, Alka-Seltzer). The results of potentiometric measurements are consistent with the method used in pharmacopoeia 100.7 to 103% of the compound was obtained, with standard deviation of RSD 0.6-1.8%. 

Andac, M., Eren, H. and Coldur, F. (2011) Determination of nitrate in leafy vegetables by flow injection analysis with potentiometric detection. J. Food Compos. Anal, 19, 457-462. 

Hassan, S. S. M., S. A. Marei, I. H. Badr, and H. A. Arida. 2001. Flow injection analysis of sulfite ion with a potentiometric titanium phosphate-epoxy based membrane sensor. Talanta 54 773-782. 

Martinovic, A., S. Cerjan-Stefenovic, and N. Radic. 2008. Flow injection analysis with two parallel detectors Potentiometric and spectrophotometric determination of thiols and ascorbic acid in mixture. /. Chem. Metrol. 2 1-12. 

Kolar, M. and D. Dobcnik. 1999. Preparation of iodide ion-selective electrode with chemically pretreated silver tube and its suitability in potentiometric flow injection analysis for the determination of vitamin C. Slovenski Kentijski Dnevi 1999 88-93. 

Direct, sensitive, selective, and rapid biosensors have been developed based on OPH, organophosphoms acid hydrolase (OPAA), and parathion hydrolase (PH). Schoning and co-workers developed a silicon-based capacitive field-effect pH sensor, which can detect 2 pM of paraoxon. " The same group prepared ampero-metric and potentiometric biosensor chips by thin-film techniques and integrated them in a flow-injection analysis (ElA) system, which can detect different OP pesticides at the low pM concentration range.Recently, mesoporous carbon and carbon black-modified electrodes have been used to develop an amperometric biosensor based on OPH. With increased sensitivity, the biosensor can detect as low as 0.12 pM (36 ppb) paraoxon. ... 

Teixeira MFS, CavaUieiro ETG, Bergamini ME, Mmaes PC, Bocchi N (2004) Use of carbon paste electrode modified with spinel-type manganese oxide as potentiometric sensor for lithium ions in flow injection analysis. Electroanalysis 16 633-639... 

This approach will not be practical for some time to come. The fundamental properties of surfactants (micelle formation, enrichment at interfaces) mean that the activity of a surfactant will usually differ from its absolute concentration (1). Just as serious is the technical problem that current surfactant-selective electrodes suffer from response which varies with their past and recent history they are also sensitive to the concentration of nonsurfactant ions. The result is that quantitative applications use electrodes not in direct measurements relating potential to concentration, but as indicators of the end point of a titration. In this latter application, it is not important that the electrode potential be exactly reproducible, but only that the potential change sharply as the surfactant concentration changes. For the titration of an anionic surfactant with a cationic surfactant, the electrode used for end point detection can be chosen to respond to either surfactant. Because of the drift in electrode potential, titrations must be conducted to an inflection in the titration curve rather than to a specific millivolt value. Details of the potentiometric titration methods can be found earlier in this chapter. The electrodes have also been demonstrated as detectors for flow injection analysis. 

An automated version of potentiometric titration can be used with flow injection analysis. In this application, termed pseudotitration (138), the mobile phase of the flow injection analysis system contains a constant concentration of the titrant, which can be either an anionic or cationic surfactant. The sample, containing either a cationic or anionic surfactant, is passed through an exponential dilution chamber prior to mixing with the mobile... 

Hassan SSM, Badr IHA, Abd-Rabboh HSM (2004) Potentiometric flow injection analysis of anionic surfactants in industrial products and wastes. Microchim Acta 144 263—269... 

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