Studi Pengaruh Modifikasi Nanofiber Polivinil Asetat/Asam Galat sebagai Lapisan Aktif pada Performa Quartz Crystal Microbalance (QCM) untuk Deteksi Gas Metilamina

Khoirun Nafisah, Prof. Drs. Roto, M.Eng., Ph.D.; Prof. Drs. Dwi Siswanta, M.Eng., Ph.D.

2026 | Skripsi | KIMIA

Metilamina (CH3NH2) merupakan senyawa amina volatil, beracun, berbau menyengat, serta banyak diproduksi dalam aktivitas industri modern. Metilamina umumnya digunakan sebagai indikator kesegaran produk perikanan sehingga diperlukan sistem deteksi yang sensitif, cepat, dan real-time. Penelitian ini dilakukan untuk mengevaluasi pengaruh modifikasi nanofiber PVAc/asam galat sebagai lapisan aktif sensor QCM untuk mendeteksi gas metilamina. 

Deposisi nanofiber PVAc/asam galat dilakukan menggunakan metode electrospinning dengan variasi konsentrasi asam galat sebesar 2%, 4%, dan 6%. Kinerja sensor dievaluasi melalui pengujian parameter performa sensor. Karakterisasi lapisan aktif nanofiber dilakukan menggunakan Fourier-transform infrared (FTIR) dan Scanning Electron Microscopy (SEM). 

Hasil FTIR menunjukkan keberadaan gugus fungsi khas PVAc dan asam galat. Citra SEM menunjukkan bahwa modifikasi dengan asam galat memengaruhi morfologi dan diameter nanofiber. Hasil penelitian membuktikan bahwa modifikasi PVAc/asam galat meningkatkan performa deteksi sensor terhadap metilamina dibandingkan PVAc murni. Sensor PVAc/GA 6% menghasilkan sensitivitas tertinggi sebesar 0,69013 Hz ppm-1 namun nilai LOD terbaik diperoleh sensor PVAc/GA 2% sebesar 3,54 ppm. Hal ini menunjukkan adanya trade-off antara sensitivitas dan presisi sensor akibat penambahan asam galat. Meskipun demikian, hasil penelitian juga menunjukkan bahwa sensor selektif terhadap metilamina dibandingkan berbagai gas interferen yang diuji. 

Methylamine (CH3NH2) is a volatile, corrosive amine compound with a pungent odor that is widely produced in modern industrial processes. Methylamine is commonly used as an indicator of the freshness of fishery products, requiring a sensitive, rapid, and real-time detection system. This study was conducted to evaluate the effect PVAc/gallic acid nanofiber modification as an active layer on a QCM sensor for detecting methylamine gas. 

Deposition of the PVAc/gallic acid nanofibers was performed using the electrospinning method with variations in gallic acid concentration of 2%, 4%, and 6%. Sensor performance was evaluated through testing of sensor performance parameters. Characterization of the nanofiber active layer was performed using Fourier-transform infrared (FTIR) and Scanning Electron Microscopy (SEM). 

FTIR results indicated the presence of characteristic functional groups of PVAc and gallic acid. SEM images showed that the modification with gallic acid affected the morphology and diameter of nanofibers. The research results demonstrate that the modification of PVAc/gallic acid enhances the sensor's detection performance for methylamine compared to pure PVAc. The PVAc/GA 6% sensor exhibited the highest sensitivity of 0.69013 Hz ppm-1 whereas the best LOD value was achieved by the PVAc/GA 2% sensor at 3.54 ppm. This indicates a trade-off between sensor sensitivity and precision due to the addition of gallic acid. Nevertheless, the results also demonstrate that the sensor is selective towards methylamine compared to various tested interfering gases. 

Kata Kunci : asam galat, metilamina, nanofiber, PVAc, sensor QCM