Flow injection analysis: potentiometric sensors

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. 

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... 

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. 

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. 

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... 

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