Nur Syakimah Ismail
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Preferred name
Nur Syakimah Ismail
Official Name
Nur Syakimah, Ismail
Alternative Name
Nur, Syakimah Ismail
Ismail, N. Syakimah
Ismail, Nur Syakimah Binti
Ismail, N. S.
Main Affiliation
Scopus Author ID
56402634600
Researcher ID
HKN-0608-2023

Research Output
Now showing 1 - 2 of 2
  • Publication
    Electrochemical detection of heavy metal ions using gold nanoparticles on carbon dots extracted from curry leaves
    ( 2024-06)
    Nur Syakimah Ismail
    ;
    Aidil Safiy Kamarul Ariffin
    ;
    Nurul Izzati Akmal Mohd Azman
    ;
    Nur Hamidah Abdul Halim
    ;
    Norhayati Sabani
    ;
    Nurjuliana Juhari
    ;
    Siti Aisyah Shamsudin
    Carbon dots (CDs) have attracted attention due to their versatility in electronic and optical properties based on precursor and type of synthesis process. Recently, many researchers have focused on using natural resources or wastes to form CDs. Four samples of CDs have been synthesized from curry leaves using a microwave-assisted approach at heating powers of 700 and 800 V with durations of 5 and 8 minutes. UV-Vis and FTIR spectra reveal the existence of carbon graphitic elements with carboxyl and hydroxyl functional groups on the surfaces of CDs. CVs of AuNPs/CDs/GS electrodes in ferricyanide disclosed that as-synthesized CDs produced using a lower heating power of 700 W exhibit pronounced electrocatalytic activity with sluggish electron transfer kinetics. Conversely, as-synthesized CDs created with a higher heating power of 800 W demonstrate reduced electrocatalytic activity but rapid electron transfer kinetics. Electrochemical detection of Pb2+ ions was observed through a sharp peak around -0.42 to -0.438 V, while detection of Hg2+ ions was observed through two anodic peaks around +0.334 to +0.408 V during a forward scan in acetate buffer (pH 4.5) on AuNPs/CDs/GS electrodes when tested individually. These distinct peaks also appeared in mixture solutions, with a slight reduction in peak current density that suggests the selectivity of the AuNPs/CDs/GS electrodes towards Pb2+ and Hg2+ ion detection. The optimum AuNPs/CDs/GS electrode for sensitive and selective detection of Pb2+ and Hg2+ was recorded using CDs D as a functional supporting matrix for AuNPs that was synthesized using a heating power of 800 W for 8 minutes.
  • Publication
    Optimization of gold nanoparticles electrodeposition duration on screen printed electrode to enhance electrochemiluminescence of nitrogen-doped carbon dots
    ( 2023-12)
    Nurul Izzati Akmal Mohd Azman
    ;
    Nur Syakimah Ismail
    ;
    Nur Hamidah Abdul Halim
    ;
    Nurjuliana Juhari
    ;
    Norhayati Sabani
    ;
    Toibah Abd Rahim
    ;
    Siti Aisyah Shamsudin
    ;
    Eiichi Tamiya
    In this work, the electrodeposition method was utilized to form gold nanoparticles on a carbon screen-printed electrode (SPE) using chronoamperometry at -0.4 V with various durations from 50 to 200 seconds. Scanning Electron Microscopy (SEM) images have proven that the electrodeposition method is capable of uniformly forming AuNPs on SPE (AuNPs- SPE). Apart from that, electrodeposition durations have increased the size of AuNPs by up to 66% based on average size measurements using ImageJ software. It can be observed that long electrodeposition durations permit the agglomeration of AuNPs on the electrode surface. The effect of electrodeposition duration on electrocatalytic performance in potassium ferricyanide and electrochemiluminescence (ECL) intensity of nitrogen-doped carbon dots (NCDs) was evaluated. Cyclic voltammetry (CV) of ferricyanide demonstrates that as the electrodeposition duration increases, AuNPs-SPE shows better electrochemical performance than bare SPE. ECL of NCDs displays that 100 s electrodeposition durations give the highest ECL intensity of 184% compared to bare SPE and have been chosen as the optimum parameter. The ECL mechanisms of bare SPE and AuNPs-SPE reveal that AuNPs- SPE has greater electrochemical and ECL performance than bare SPE, as evidenced by the CV of AuNPs-SPE having a faster reduction current, which rises to 87.2% ECL intensity and 510 mV faster ECL occurrence. These phenomena confirmed that the electrodeposition of AuNPs has improved the conductivity of SPE.
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