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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.

No MeSH data available.


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Dependence of PNR electrode potential on concentration of inorganic anions.
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f2-sensors-08-00594: Dependence of PNR electrode potential on concentration of inorganic anions.

Mentions: The choice of appropriate environment is essential for measurements with sensitive electropolymerized electrodes [18]. First, the PNR electrodes were tested with inorganic ions in distilled water to choose the ion that best maintained constant ionic strength. The lipophilicity of the selected anions decreases in the sequence SCN- > I- > NO3- > Cl- > SO42- > H2PO4- [21]. PNR electrodes prepared from both an aqueous and organic solution of neutral red gave practically no response to any of the hydrophilic anions (Fig. 2). The electrodes are only sensitive to high concentrations of lipophilic ions such as SCN- and I-. As a result, the chlorides and nitrates of alkali metals are suitable for adjusting ionic strength, because they do not affect the signal of the PNR electrode.


Optimalization of Poly(neutral red) Coated-wire Electrode for Determination of Citrate in Soft Drinks
Dependence of PNR electrode potential on concentration of inorganic anions.
© Copyright Policy
Related In: Results  -  Collection

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

f2-sensors-08-00594: Dependence of PNR electrode potential on concentration of inorganic anions.
Mentions: The choice of appropriate environment is essential for measurements with sensitive electropolymerized electrodes [18]. First, the PNR electrodes were tested with inorganic ions in distilled water to choose the ion that best maintained constant ionic strength. The lipophilicity of the selected anions decreases in the sequence SCN- > I- > NO3- > Cl- > SO42- > H2PO4- [21]. PNR electrodes prepared from both an aqueous and organic solution of neutral red gave practically no response to any of the hydrophilic anions (Fig. 2). The electrodes are only sensitive to high concentrations of lipophilic ions such as SCN- and I-. As a result, the chlorides and nitrates of alkali metals are suitable for adjusting ionic strength, because they do not affect the signal of the PNR electrode.

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