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Cathodic Electrochemical Detection of Nitrophenols at a Bismuth Film Electrode for Use in Flow Analysis
Author(s) -
Hutton Emily A.,
Ogorevc Božidar,
Smyth Malcolm R.
Publication year - 2004
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/elan.200402979
Subject(s) - amperometry , bismuth , detection limit , supporting electrolyte , analytical chemistry (journal) , electrode , chemistry , voltammetry , electrochemistry , cyclic voltammetry , glassy carbon , electrolyte , chromatography , buffer solution , organic chemistry
The bismuth film electrode (BiFE) is presented for use in both batch voltammetric and flow injection (FI) amperometric detection of some nitrophenols (2‐nitrophenol, 2‐NP; 4‐nitrophenol, 4‐NP; 2,4‐dinitrophenol, 2,4‐DNP). The bismuth film was deposited ex situ (batch measurements) and in‐line (FI) onto a glassy carbon substrate electrode. Batch analysis of the nitrophenols was carried out in 0.04 M Britton Robinson (BR) buffer pH 4, while for FI measurements, a carrier/electrolyte solution composed of 0.1 M BR buffer pH 4 mixed with methanol (20+80, v/v%) was employed to resemble media used in preconcentration/clean‐up and flow separation sample pretreatment procedures. Under batch conditions, the voltammetric behavior of the nitrophenols was examined for dependence on medium pH in the range of 2 to 10. Employing the square‐wave voltammetry mode, the limits of detection were 0.4 μg L −1 , 1.4 μg L −1 , and 3.3 μg L −1 for 2‐NP, 4‐NP, and 2,4‐DNP, respectively. Under flow conditions, a simple in‐line electrochemical bismuth film renewal procedure was tested and shown to provide very good inter‐ and intra‐electrode reproducibility of the current signals at low μg L −1 analyte concentrations. The limits of detection for 2‐NP, 4‐NP and 2,4‐DNP obtained using FI and amperometric detection at −1.0 V (vs. Ag/AgCl) were 0.3 μg L −1 , 0.6 μg L −1 and 0.7 μg L −1 , respectively, with linear ranges extending up to 20 μg L −1 . The attractive performance of the BiFE under flow analysis conditions offers great promise with respect to its detection capability and to its use for a prolonged period of time with no need for inconvenient removal of the electrode from the system for mechanical surface treatment.