scholarly journals Simultaneously determination of bisphenol A and uric acid by zinc/aluminum-layered double hydroxide-2-(2,4- dichlorophenoxy) propionate paste electrode

Author(s):  
Nurul Syahida Mat Rais ◽  
Sensors ◽  
2019 ◽  
Vol 19 (4) ◽  
pp. 941 ◽  
Author(s):  
Rahadian Zainul ◽  
Nurashikin Abd Azis ◽  
Illyas Md Isa ◽  
Norhayati Hashim ◽  
Mohamad Syahrizal Ahmad ◽  
...  

This paper presents the application of zinc/aluminium-layered double hydroxide-quinclorac (Zn/Al-LDH-QC) as a modifier of multiwalled carbon nanotubes (MWCNT) paste electrode for the determination of bisphenol A (BPA). The Zn/Al-LDH-QC/MWCNT morphology was examined by a transmission electron microscope and a scanning electron microscope. Electrochemical impedance spectroscopy was utilized to investigate the electrode interfacial properties. The electrochemical responses of the modified electrode towards BPA were thoroughly evaluated by using square-wave voltammetry technique. The electrode demonstrated three linear plots of BPA concentrations from 3.0 × 10−8–7.0 × 10−7 M (R2 = 0.9876), 1.0 × 10−6–1.0 × 10−5 M (R2 = 0.9836) and 3.0 × 10−5–3.0 × 10−4 M (R2 = 0.9827) with a limit of detection of 4.4 × 10−9 M. The electrode also demonstrated good reproducibility and stability up to one month. The presence of several metal ions and organic did not affect the electrochemical response of BPA. The electrode is also applicable for BPA determination in baby bottle and mineral water samples with a range of recovery between 98.22% and 101.02%.


2021 ◽  
Author(s):  
TCHEUMI Herve Leclerc ◽  
KAMENI WENDJI Aude Peggy ◽  
TONLE KENFACK Ignas ◽  
NGAMENI Emmanuel

Abstract Environmental pollution by usage of pesticides as fenuron increases health risk, due to carcinogenic and teratogenic properties of these compounds. There are needs to develop a rapid and cheaper detection methods for quantification of fenuron. In this work, an inorganic-organic composite material was obtained by intercalation of sodium dioctylsulfosuccinate (DSS) within the interlayer space of a Nickel-Aluminum Layered Double Hydroxide (NiAl-LDH). The structure of the pristine LDH and the intercalated-LDH was confirmed using Fourier transform infrared spectroscopy, X-ray diffraction and thermal analysis. The modified LDH was used to elaborate an amperometric sensor for fenuron herbicide by differential pulse voltammetry (DPV) via a carbon paste electrode (CPE). The electrochemical procedure for fenuron analysis was based on the immersion of the working electrode in the electrolytic solution containing appropriate amount of herbicide, followed by voltammetry detection without any preconcentration step. The peak current obtained on the CPE modified by the organo-LDH was 2-fold higher in comparison with the pristine LDH/CPE. The observed increase in the signal of fenuron was attributed to the high organophilic character of this composite material induced by the modification using DSS. The effects of some experimental parameters (pH of medium and percentage of the modifier in the paste) on the stripping response were investigated in order to optimize the sensitivity of the organo-LDH modified electrode. Linear calibration curves were obtained in the fenuron concentration ranging from 0.5 to 1 μmol.L -1 and 1 to 5 μmol.L -1 . The limit of detection (LOD) calculated on the basis of a signal-to-noice ratio of 3 was 1.8×10 -9 mol.L -1 (low concentration range) and the limit of quantification (LOQ) was 6×10 -9 mol.L -1 . The interference effect of various inorganic ions likely to influence the stripping determination of the fenuron was also examined, and the applicability of the method was verified by the determination of fenuron in a river sample collected down-town Yaoundé.


2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Herve Leclerc Tcheumi ◽  
Aude Peggy Kameni Wendji ◽  
Ignas Kenfack Tonle ◽  
Emmanuel Ngameni

In this work, a Layered Double Hydroxide (NiAl-LDH) was obtained by coprecipitation method and used to elaborate an electrochemical sensor for the determination of isoproturon, which is a hazardous pollutant, widely used in agriculture, and its residue is distributed into aqueous environment through run-off and leaching from the soil. Various physicochemical techniques such as FT-IR spectroscopy, X-ray diffraction, and thermal analysis were used to characterize this material. The anionic exchange capacity of NiAl-LDH on carbon paste modified electrode was investigated toward [Fe(CN)6]3- using cyclic voltammetry. Used as electrode modifier of carbon paste electrode for isoproturon detection, a remarkable increase in isoproturon signal on modified carbon paste electrode by LDH was observed. The peak current obtained after 3 min of preconcentration in 25 μM ISO on NiAl-LDH/CPE was 2.6 times higher than that exhibited by the same analyte on the unmodified CPE, thereby opening the way to the development of a sensitive method for the detection of ISO. Other parameters that can affect the stripping response (preconcentration time, pH of detection medium, and LDH loading within the paste) were investigated to optimize the proposed sensor. After optimization, a linear calibration curve was obtained in the concentration range from 2 × 10−8 to 1.8 × 10−7 M, leading to a detection limit of 1 × 10−9 M (S/N = 3). The relative standard deviation for 5 identical measurements was 2.7%. The interfering effect of some compounds and ions was examined on the stripping response of ISO. The applicability of the method was verified by the determination of ISO in spiked water sample.


2021 ◽  
Author(s):  
Younes Bahadori ◽  
Habib Razmi

A novel electrochemical sensor based on the Cu-Al layered double hydroxide (Cu-Al LDH) by chicken feet yellow membrane (CFYM) on graphenized pencil graphite electrode (GPGE) was designed. The present modified...


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