Direct detection of ammonium ion by means of oxygen electrocatalysis at a copper-polyaniline composite on a screen-printed electrode

• We describe a composite material for use in electrochemical oxygen reduction. A screen-printed electrode (SPE) was consecutively modified with electrodeposited copper, a Nafion membrane and electropolymerized polyaniline (PANi) to give an electrocatalytic composite of type PANi/Nafion/Cu2O/SPE that displays good electrical conductivity at neutral pH values. It is found that the presence of ammonia causes complex formation with Cu(I), and this causes electroreduction of oxygen to result in an increased cathodic current. The finding was applied to the quantification of ammonium ions in the 1 to 1000 μM concentration range by amperometry at −0.45 V (vs. Ag/AgCl). This Faradaic phenomenon offers the advantage of direct voltammetric detection, one of the lowest known limits of detection (0.5 μM), and high sensitivity (250 mA∙M−1∙cm−2). It was applied to the determination of ammonium ion in human serum where it compared well with the photometric routine approach for clinical analysis using glutamate dehydrogenase. [Figure not available: see fulltext.]

Ämnesord

NATURVETENSKAP  -- Data- och informationsvetenskap (hsv//swe)

NATURAL SCIENCES  -- Computer and Information Sciences (hsv//eng)

MEDICIN OCH HÄLSOVETENSKAP  -- Medicinska och farmaceutiska grundvetenskaper -- Andra medicinska och farmaceutiska grundvetenskaper (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Basic Medicine -- Other Basic Medicine (hsv//eng)

Nyckelord

Amperometry

Conductive polymer

EDX

Electrochemical impedance spectroscopy

Nanocomposite

SEM

Serum analysis

XPS

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