Malaysian Journal of Analytical Sciences Vol 25 No 6 (2021): 1122 - 1137

 

 

 

 

SYNTHESIS OF HYBRID CARBON QUANTUM DOTS FROM Tamarindus indica AND Mangifera indica LEAVES FOR THE DETECTION OF MERCURY (Hg²⁺) ION IN PURIFIED WATER AND SIMULATED SEAWATER

 

(Sintesis Titik Kuantum Karbon Hibrid dari Daun Tamarindus indica dan Mangifera indica bagi Pengesanan Ion Merkuri (Hg²⁺) dalam Sampel Air Tulen dan Simulasi Air Laut)

 

Rejie C. Magnaye*, Riszel B. De Castro, Kenneth B. Gomez, Rex Gregor M. Laylo, Aljon Joseph G. Maderazo

 

Chemical and Food Engineering Department

College of Engineering, Architecture and Fine Arts

Batangas State University,

Golden Country Homes Subdivision, Alangilan, Batangas City, Philippines

 

*Corresponding author:  rejie.magnaye@g.batstate-u.edu.ph

 

 

Received:  16 July 2021; Accepted: 28 October 2021; Published:  27 December 2021

 

 

Abstract

Mercury (Hg²⁺) ion is considered as one of the most lethal heavy-metal contaminants accounting for its extreme persistence, bioaccumulation, and toxicity. The objective of this study is to synthesize hybrid carbon quantum dots (h-CQDs) for the detection of Hg²⁺ ion in purified water and simulated seawater using ratiometric fluorescence assay between blue carbon quantum dots(b-CQDs) produced from Tamarindus indica leaves and green carbon quantum dots(g-CQDs) produced from Mangifera indica leaves. The optical properties of the produced CQDs were determined using UV-Vis spectrophotometer which explained the quenching of g-CQDs’ photoluminescence and stability of b-CQDs upon addition of Hg²⁺. The research also includes the effect of volume ratio and time of microwave irradiation in the photoluminescence intensity ratio of h-CQDs and the influence of increasing Hg²⁺ concentration in both purified water and simulated seawater. The mathematical correlation between PL intensity ratio and concentration was found to be a rational equation for both purified and simulated seawater. Using simulated seawater, the result showed in the model has no significant difference with the detected concentrations using atomic absorption spectroscopy. Furthermore, the generated model exhibits dynamic range between 394 ppb and 23.85 ppm.

 

Keywords:  quantum dots, g-CQDs, b-CQDS, mercury detection, carbon quantum dots

 

Abstrak

Ion merkuri (Hg²⁺) dianggap sebagai satu pencemar logam berat maut berdasarkan sifatnya yang kekal, bioakumulasi, dan ketoksikan. Objektif kajian ini ialah menyediakan sintesis titik kuantum karbon hibrid (h-CQDs) bagi pengesanan ion Hg²⁺ dalam air tulen dan simulasi air laut mengunakan ujian pendaflour ratiometrik di antara titik kuantum karbon biru (b-CQDs) di hasil dari daun Tamarindus indica dan titik kuantum karbon hijau (h-CQDs) dari daun Mangifera indica. Sifat optikal yang terhasil bagi CQDs telah ditentukan melalui spektrofotometer UV-Vis menjelaskan pelindapan fotoluminesens g-CQDs dan kestabilan b-CQDs dengan penambahan Hg²⁺. Kajian juga termasuk melihat kesan nisbah isipadu dan masa bagi penyinaran gelombang mikro dalam nisbah keamatan fotoluminesens h-CQDs dan pengaruh peningkatan kepekatan Hg²⁺ bagi kedua-dua air tulen dan simulasi air laut. Korelasi matematik di antara nisbah keamatan PL dan kepekatan telah di ketahui menjadi persamaan sepadan bagi kedua-dua air tulen dan simulasi air laut. Mengunakan simulasi air laut, hasil menunjukkan model memberikan perbezaan tidak signifikan bagi kepekatan yang dikesan melalui analisis spektroskopi serapan atom. Selanjutnya, model yang dihasilkan memberi julat dinamik antara 394 ppb dan 23.85 ppm.

 

Kata kunci:  titik kuantum, g-CQDs, b-CQDS, pengesanan merkuri, titik kuantum karbon

 

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