Sintesis Nanopartikel Perak Tertiolasi dalam Matriks Kitosan sebagai Sensor untuk Deteksi Ion Merkuri

Yulirohyami, Prof. Drs. Mudasir, M.Eng., Ph.D.; Prof. Drs. Dwi Siswanta, M. Eng., Ph.D.; Prof. Dr. Is Fatimah, S.Si., M.Si.

2026 | Disertasi | S3 Ilmu Kimia

Sintesis nanopartikel perak tertiolasi dalam matriks kitosan (AgNPs-SH@Cts) sebagai sensor merkuri dikembangkan melalui pendekatan kimia hijau berbantuan ultrasonik. Penelitian ini bertujuan mengatasi keterbatasan stabilitas AgNPs akibat agregasi dan oksidasi serta mengevaluasi pengaruh ligan ditizon, sistein, dan glutation terhadap karakteristik fisikokimia, sensitivitas, selektivitas, dan stabilitas sensor elektrokimia untuk ion Hg2+, sekaligus menentukan sistem modifikasi yang sesuai untuk analisis merkuri pada sampel air.

AgNPs disintesis menggunakan ekstrak Hydrocotyle umbellata dan Centella asiatica pada variasi waktu dan temperatur sonikasi, ditandai oleh puncak LSPR 400–500 nm. Citra TEM menunjukkan partikel berbentuk bulat dengan diameter rata-rata 7,39; 5,43; dan 4,49 nm untuk AgNPs yang distabilkan ditizon, sistein, dan glutation dalam matriks kitosan. Keberhasilan sintesis dikonfirmasi melalui FTIR, XRD, analisis morfologi, serta EDX yang menunjukkan keberadaan Ag, S, dan N.

Sensor difabrikasi pada screen-printed electrodes (SPEs) dengan metode penetesan. Pengujian cyclic voltammetry menggunakan [Fe(CN)6]3–/4– 0,005 M menunjukkan peningkatan kinerja yang berkorelasi dengan luas permukaan aktif elektrokimia. Tiolasi meningkatkan Ipa sebesar 423%–515?n mengubah Ipc sebesar 331%–502%.

SPEs-AgNPs-SH@Cts menunjukkan stabilitas pada sepuluh pengulangan dan selektivitas tinggi terhadap Hg2+ di hadapan berbagai ion pengganggu. Sensor memberikan linearitas rata-rata 0,9979, sensitivitas 1,20±0,03–2,12±0,07 µA/ppb, dan limit deteksi 0,15–0,20 ppb. Analisis sampel air menghasilkan RSD 2,27%–8,12?n perolehan kembali (82,93±0,02–102,35±0,09)%. Sensor dapat digunakan kembali serta mendukung analisis secara cepat, sederhana, akurat, dan ramah lingkungan.

Thiolated silver nanoparticles embedded in a chitosan matrix (AgNPs-SH@Cts) were developed as an electrochemical sensor for mercury detection using an ultrasound-assisted green synthesis approach. This study aimed to improve the stability of AgNPs against aggregation and oxidation and to evaluate the effects of dithizone, cysteine, and glutathione on their physicochemical characteristics and sensing performance toward Hg2+.

AgNPs were synthesized using Hydrocotyle umbellata and Centella asiatica extracts under varied sonication times and temperatures, as indicated by localized surface plasmon resonance peaks at 400–500 nm. TEM images showed spherical particles with average diameters of 7.39, 5.43, and 4.49 nm for AgNPs stabilized with dithizone, cysteine, and glutathione, respectively. Successful synthesis was confirmed by FTIR, XRD, morphological characterization, and EDX analysis, which identified Ag, S, and N.

The sensors were fabricated on screen-printed electrodes (SPEs) using a drop-casting method. Cyclic voltammetry using 0.005 M [Fe(CN)6]3–/4– demonstrated enhanced electrochemical performance associated with an increased electrochemically active surface area. Thiolation increased the anodic peak current by 423%–515% and altered the cathodic peak current by 331%–502%.

The modified SPEs exhibited good stability over ten repeated measurements and high selectivity toward Hg2+ in the presence of various interfering ions. The sensors showed an average linearity of 0.9979, sensitivities of 1.20±0.03–2.12±0.07 µA/ppb, and detection limits of 0.15–0.20 ppb. Water sample analysis yielded relative standard deviations of 2.27%–8.12% and recoveries of (82.93±0.02–102.35±0.09)%. The sensor is reusable and supports rapid, simple, accurate, and environmentally friendly analysis.

Kata Kunci : nanopartikel perak tertiolasi, kitosan, screen-printed electrode, sensor elektrokimia, ion merkuri, square-wave anodic stripping voltammetry