Poly -modified electrode, flow injection analysis

All potentials vs. screen-printed pseudo Ag/AgCl reference, except values marked with double-dagger (J), which are vs. screen-printed Ag/Pd, and 02 those marked with asterisk ( ), which are vs. Ag/3M AgCl double-junction reference electrode. Abbreviations LDH lactate dehydrogenase, LOD lactate oxidase, PVA-SbQ styrlpyridinium-modified poly(vinyl alcohol), FIA flow injection analysis. aLinear ranges using a dialysis system. 

Carballo, R., V.C. DaH Orto, A. Lo Balbo, and I. Rezzano (2003). Determination of sulfite by flow injection analysis using poly[Ni-(protoporphyrin DC)] chemically modified electrode. Sensor Actuators B Chem. 88,155-161. 

The second part describes the application of this automated potentiostat as an electrochemical detector for various electro-inactive anionic species nitrate (NOg ), nitrite (NOg"), sulfate (SO "), chloride (CD, etc. (1,2). The electrochemical detection involves the use of a conducting poly(3-methylthiophene) (P3MT) polymer modified platinum electrode in a flow injection analysis (FIA) mode. 

Flow Injection Analysis (FIA) with Poly(3-methylthiophene) Modified Electrodes... 

The same authors further improved the CNT-modified biosensors for detection of OP compounds based on a layer-by-layer immobilization of CNTs, polymer, and AChE on the surface of GC electrodes (Liu and Lin, 2006). AChE was sandwiched with poly(diallyldimethylammonium chloride) layers on the surface of CNTs. The OP biosensor developed in this way was used to detect paraoxon (Figure 62.7) at levels as low as 4 X 10 M with a 6 min response time in flow injection analysis. The high stability of the sensors was another merit of this biosensor no deterioration in the response was observed after 1 week of continuous... 

One of the first reported uses of a conducting polymer moditied electrode for the detection of anions by flow ipjection analysis (FIA) utilized poly(pyrrole) 13). Low detection limits were achieved. However, poly(pyrrole) is irreversibly oxidized in the presence of oxygen at potentials of around +1.0 volts. Poly(3-methylthiophene) does not exhibit this behavior. Therefore, poly(3-methylthiophene appeared to be a good candidate as an electrochemical detector for anionic species by FIA with electrochemical detection at an poly(3-methylthiophene) modified electrode. Also P3MT does not need to be undoped (cyded between the negative and positive detection potentials) between successive injections as many other polymer systems must. 

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