Pembuatan dan Karakterisasi Membran Elektroda Selektif Ion Menggunakan Ionofor 7,16-DI-(2-METHYLQUINOLINE)-1,4,10,13-TETRAOXA-7,16-Diazacyclooctadecane (DQDC) untuk Penentuan Merkuri Secara Potensiometri

Abstract

Ionophore of 7,16-Di-(2-Methylquinoline)-1,4,10,13-Tetraoxa-7,16-Diaza cyclooctadecane (DQDC from material of 1,4,10,13-Tetraoxa-7,16-Diazacyclooctadecane (DC) with 2- Chloromethylquinoline (C10H8ClN) have successfully been created by addition method. The result of FTIR analysis showed that ionophore contain carbonyl functional group as indicate ionophore DQDC presence. The measurement of DQDC ionophore’s melting point were about 800±C. Ionophore DQDC as the material of membrane to the mercury sensor were made through the sputtering method, Furthermore the membrane is formed into ion selective electrode of mercury (ISE-Hg) on flexible small pipe PVC covered with tungsten electrode. The average range of flux and rejection coefficient of membran was (0,0087 0,0001) L/m2± hours and (82,91 7,30)% with the shape of pore surrounded (38,40 ± 0,01) μm, the stability of the membrane was 94% for 30 days. Then ISE-Hg was arranged together with allowing electrode (Ag/AgCl) as the completely for potentiometric to detect the existence of mercury in liquid. The result of measure throught injection (Hg(NO3)2± on the solution was recorded by recorder, and the electrode gave Nernstian respon is about 25,820,1 mV per decade concentration of Hg2+ with range linearity lies between 5 x 10-9 until 1 x 10-6 M Hg2+±. It showed that membrane can stored the electric charge that inversely proportional to frequency. The average range of membran capacity is (0,60-1,0 0,001) nF, while the membrane impedance (10,0-20,0 ± 0,01) kΩ and the conductivity (0,037 ± 0,01) kmho, and also with the result of loss coefficient decreased by the increasing of frequency and the average result of measurement ((0,32 ± 0,01). The result of UV-VIS analysis showed the thickness of the membrane 7,48 μm and the gap energy of is 4,095 eV, it’s mean that membrane is as an insulator. The result of SEM stated that on the membran still having the pore that have diameter around 38,57 μm and have not been evenly distibuted, beside that the result of XRD showed the shape of membran crystal is Orthorhombic with a = 5.0832 Å; b = 6.7615Å; c = 4.5194 Å and the average of grain size around 4,67 Å.

Ionofor 7,16-Di-(2-Methylquinoline)-1,4,10,13-Tetraoxa-7,16-Diazacycloocta decane (DQDC) dari bahan 1,4,10,13-tetraoxa-7,16 diazacyclooctadecana (DC) dengan 2-chloromethylquinoline (C10H8ClN) telah berhasil di buat melalui metoda addisi. Hasil analisis FTIR menunjukkan bahwa terdapat gugus fungsi karbonil sebagai penunjuk terbentuk ionofor DQDC. Pengukuran melting point ionofor DQDC ini berada disekitar 800±C. Ionofor DQDC sebagai bahan membran untuk sensor merkuri dibuat melalui metoda sputtering, selanjutnya membran dibentuk menjadi elektroda selektif ion merkuri (ESI-Hg) pada pipa kecil bening dilengkapi dengan elektoda tungsten. Nilai fluks rata-rata dan koefisien rijeksi membran (0,0087 0,0001) L/m2± jam dan (82,91 7,30)% dengan ukuran pori sekitar (38,40 ±0,01) μm, stabilitas membran 94% selama 30 hari. ESI-Hg kemudian disusun bersama elektroda referensi Ag/AgCl sebagai kelengkapan alat potensiometri untuk mendeteksi keberadaan merkuri di dalam cairan. Hasil pengukuran melalui injeksi (HgNO3)2 pada ±larutan direkam pada rekorder, menghasilkan respon Nernstian sebesar 25,820,1 mV/dekade untuk Hg2+ dengan konsentrasi 5 x 10-9 sampai 1 x 10-6 M Hg2+±. Hasil pengukuran menunjukkan bahwa membran dapat menyimpan muatan listrik yang besarnya berbanding terbalik dengan frekuensi. Nilai rata-rata kapasitas membran adalah (0,60-1,0 0,001) nF, sementara impedansi membran (10,0-20,0 ± 0,01) kΩ dan konduktansinya (0,037 ± 0,01) kmho, demikian juga dengan hasil loss coefficient menurun dengan bertambahnya frekuensi dan rata-rata hasil pengukuran adalah (0,32 ± 0,01). Hasil analisis UV-Vis menunjukkan bahwa ketebalan membran 7,48μm dan energi gap sebesar 4,095 eV artinya bahwa membran bersifat sebagai isolator. Hasil SEM menyatakan bahwa pada membran masih terdapat rongga berdiameter rata-rata 38,57 μm dan belum merata, selain itu hasil XRD menunjukkan bahwa bentuk kristal membran adalah ortorhombik dengan a = 5.0832 Å; b = 6.7615 Å ; c = 4.5194 Å dan ukuran rata-rata partikel (grain size) sebesar 4,67 Å.