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Optimalization of Poly(neutral red) Coated-wire Electrode for Determination of Citrate in Soft Drinks

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ABSTRACT

This report presents an optimization of potentiometric measurements with citrate-selective electropolymerized poly(neutral red) electrodes. The optimal background electrolyte for these measurements is a TRIS buffer with nitrate at pH 8.5. The electrodes described here exhibit stable and reproducible near-Nernstian response to citrates with a low detection limit of 6 × 10-6 M. Electrodes polymerized from sulfuric acid and acetonitrile are compared in detail. Simple and sensitive method for quantification of citrate in real-life samples by potentiometry with poly(neutral red) electrodes are presented. Data from potentiometric measurements of citrate are compared with capillary electrophoresis.

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Potential dependence of both types of PNR electrodes on the age of the electrode for three citrate concentrations: 0.001 (○), 0.01 (▹) and 0.1 M (*).
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f6-sensors-08-00594: Potential dependence of both types of PNR electrodes on the age of the electrode for three citrate concentrations: 0.001 (○), 0.01 (▹) and 0.1 M (*).

Mentions: During long-term stability experiments, the electrodes had only a low drift, except for the first few measurements, where the potential drifted several tens of milivolts (Fig. 6). The potential stability of the polymeric films is often determined by changes in the composition of the polymeric film after preparation. The oligomers that were incorporated into the polymeric film are gradually washed out during the conditioning of electrodes [28]. In addition, the polymer rearranges its structure on the support metal during conditioning [25]. On the 11th day the potential became stable, although a small drift was observed. Nevertheless, the electrode parameters of PNR electrodes such as their slope and concentration range remain unchanged during this period. The drift can be effectively eliminated by calibrating the ISE just before measuring the sample [29].


Optimalization of Poly(neutral red) Coated-wire Electrode for Determination of Citrate in Soft Drinks
Potential dependence of both types of PNR electrodes on the age of the electrode for three citrate concentrations: 0.001 (○), 0.01 (▹) and 0.1 M (*).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3672997&req=5

f6-sensors-08-00594: Potential dependence of both types of PNR electrodes on the age of the electrode for three citrate concentrations: 0.001 (○), 0.01 (▹) and 0.1 M (*).
Mentions: During long-term stability experiments, the electrodes had only a low drift, except for the first few measurements, where the potential drifted several tens of milivolts (Fig. 6). The potential stability of the polymeric films is often determined by changes in the composition of the polymeric film after preparation. The oligomers that were incorporated into the polymeric film are gradually washed out during the conditioning of electrodes [28]. In addition, the polymer rearranges its structure on the support metal during conditioning [25]. On the 11th day the potential became stable, although a small drift was observed. Nevertheless, the electrode parameters of PNR electrodes such as their slope and concentration range remain unchanged during this period. The drift can be effectively eliminated by calibrating the ISE just before measuring the sample [29].

View Article: PubMed Central - PubMed

ABSTRACT

This report presents an optimization of potentiometric measurements with citrate-selective electropolymerized poly(neutral red) electrodes. The optimal background electrolyte for these measurements is a TRIS buffer with nitrate at pH 8.5. The electrodes described here exhibit stable and reproducible near-Nernstian response to citrates with a low detection limit of 6 × 10-6 M. Electrodes polymerized from sulfuric acid and acetonitrile are compared in detail. Simple and sensitive method for quantification of citrate in real-life samples by potentiometry with poly(neutral red) electrodes are presented. Data from potentiometric measurements of citrate are compared with capillary electrophoresis.

No MeSH data available.


Related in: MedlinePlus