Browsing by Author "Bhavana Arora"

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Application of polymer-modified hanging mercury drop electrode in the indirect determination of certain β-lactam antibiotics by differential pulse, ion-exchange voltammetry
(Wiley-VCH Verlag, 2003) Bhim Bali Prasad; Bhavana Arora
A selective and sensitive polymer-modified electrode was developed for β-lactam antibiotics (cefaclor, amoxycillin and ampicillin) present in formulated and blood plasma samples for the quantitative analysis in aqueous environment. The detection was made using an ion-exchange voltammetric technique, in differential pulse mode, on poly(N-chloranil N,N,N′,N′ -tetramethylethylene diammonium dichloride)-modified hanging mercury drop electrode of a three-electrode system (PAR Model 303A) attached with a Polarographic Analyzer/Stripping Voltammeter (PAR Model 264A). Antibiotics, which are electroinactive compounds, were essentially converted to their electroactive oxazolone analogues through acid treatment under drastic conditions (0.1 mol L-1 HCl, ∼85 °C, 2 h). These analytes in the form of their respective oxazolones were indirectly analyzed by oxazolone entrapment in the polymeric film through ion-exchange process at modified electrode surface (accumulation potential -0.20 V (vs. Ag/AgCl), accumulation time 120 s, pH 7.4, KH2PO4-NaOH buffer (ionic strength 0. 1 mol L-1), scan rate 10 mV s-1, pulse amplitude 25 mV). The limit of detection of cefaclor-derived oxazolone was found to be 2.12 nmol L-1 (0.82 ppb, S/N 3, RSD 3.21%) in terms of cefaclor (a representative β-lactam) concentration.
Imprinted polymer-modified hanging mercury drop electrode for differential pulse adsorptive stripping voltammetric analysis of a diquat herbicide
(Wiley-VCH Verlag, 2003) Bhim Bali Prasad; Bhavana Arora
An imprinted polymer modified hanging mercury drop electrode (HMDE) in Model 303A system in conjunction with a PAR Model 264A Polarographic Analyzer/Stripping Voltammeter has been used for the selective analysis of a diquat herbicide viz., 5,6-dihydropyrazino[1,2,3,4-[lmn]-1,10-phenanthrolinium dichlorides in differential pulse cathodic stripping voltammetry mode. Complex aqueous samples (drinking water and agricultural soil suspension), spiked with a diquat herbicide, were directly analyzed by the adsorptive accumulation of the analyte over the working electrode (accumulation potential -0.8 V (vs. Ag/AgCl), accumulation time 120 s, pH 7.0, supporting electrolyte 0.1 M KCl, scan rate 10 mV s-1, pulse amplitude 25 mV). The limit of detection for diquat herbicide was found to be 0.34 nmolL-1 (0.1 ppb, RSD 2%, S/N=2).
Trace analysis of 1,10-phenanthroline based herbicide in water and soil samples
(2002) Bhim Bali Prasad; Bhavana Arora
A sensitive analytical procedure for diquat herbicide viz. 5,6-dihydropyrazino[1,2,3,4-lmn]-1,10-phenanthrolinium dichlorides in drinking water and soil samples, using differential pulse adsorptive stripping voltammetry (DPAdSV) has been developed. This involved the adsorptive accumulation of a diquat herbicide onto a hanging mercury drop electrode [accumulation potential -0.8 V vs Ag/AgCl, accumulation time 60 s, pH 7.0, ionic strength 0.1 M] for DPAdSV measurement. The detection limit for diquat herbicide was as low as 0.034 μmol L-1 level (S/N 2, RSD 2.9%) at an accumulation time of 60 s.