Development of poly(3-aminophenylboronic acid) modified graphite rod electrode suitable for fluoride determination

• 3-aminophenylboronic acid was electrochemically polymerized on the graphite rod electrode.
• The polymeric layer formed over carbon surface was sensitive towards fluoride ions.
• The electrode was applied for the determination of fluoride in toothpaste containing some interfering ions.

Poly(3-aminophenylboronic acid), (PAPBA) film was formed on the graphite rod surface by potential cycling. The PAPBA-modified graphite rod (PAPBA/GR) electrode prepared in this way was used for potentiometric fluoride determination. The linear calibration range was from 5×10−4 to 5×10−2 M with the slope of the linear part of the calibration curve of 42.5 mV/log C. No interference effect of the most common ions such as sodium, potassium, chloride, nitrate, iodide, calcium, zinc, aluminum, sulfate and sorbitol was observed during electrochemical determination of fluoride. On the other hand, the PAPBA/GR electrode showed not only good sensitivity and selectivity, but also relatively rapid response to changes of analyte concentrations in the range of 20 s. The sensor was successfully applied for fluoride determination in real sample – toothpaste.

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