Electronic Theses and Dissertation

Pada penelitian ini telah berhasil dibuat elektroda selektif ion (ISE) untuk ion Al3+ menggunakan minyak jarak (Ricinus communis. L) berbasis membran poliuretan (PU) dengan bahan aktif 1,10-fenantrolin. Penelitian ini bertujuan untuk mempelajari pengaruh ion asing dan pengaruh Total Ionic Strength Adjustment Buffer (TISAB) terhadap respon ESI Al3+. Pengaruh ion asing diukur dengan menentukan koefisien selektivitas (Kij) menggunakan metode larutan terpisah. Larutan yang diukur yaitu ion utama Al3+ dan ion asing Na+, K+, Li+ , Pb2+, Ca2+, Co2+, Cu2+, Ni2+, Cr3+, dan Fe3+ dengan rentang konsentrasi 1x10-9 – 1x10-4 M. Hasil penelitian menunjukkan keberadaan ion asing tidak mempengaruhi kinerja ESI Al3+ dengan perolehan nilai Kij < 1. Urutan selektivitas ESI Al3+ yaitu Fe3+ > Cr3+ > Pb2+ > Cu2+ > Ni2+ > Co2+ > Ca2+ > Li+ > Na+ > K+. Pengaruh konsentrasi larutan TISAB diuji terhadap linieritas, rentang linier, LOD, dan LOQ. Hasil menunjukkan nilai sensitivitas yang tinggi pada konsentrasi TISAB 1x10-1, 1x10-2, 1x10-3, 1x10-4, dan 1x10-5 berturut-turut yaitu 18,50 ± 0,71, 18,52 ± 1,4, 18,18 ± 0,05, 18,89 ± 0,5 dan 19,15 ± 0,27. Respon ESI Al3+ yang diukur tanpa larutan TISAB mempunyai rentang linier yang lebih pendek yaitu 10-4 – 10-9 M, setelah dilakukan penambahan larutan TISAB rentang linier menjadi lebih lebar yaitu 10-4 – 10-10 M. Nilai LOD dan LOQ yang lebih rendah dengan penambahan TISAB, serta koefisien determinasi ≈ 1 yang berarti bahwa ESI Al3+ memiliki linieritas yang baik terhadap ion Al3+. Maka hasil dari penelitian ini diperoleh konsentrasi larutan TISAB terbaik adalah 1x10-5. Serta didapatkan nilai kij ESI Al3+ berbasis membran PU pada berbagai konsentrasi ion asing Na+, K+, Li+, Pb2+, Ca2+, Co2+, Cu2+, Ni2+, Cr3+, dan Fe3+.

In this research, an ion selective electrode (ISE) for Al3+ ions has been successfully developed using castor oil (Ricinus communis L) based on a polyurethane (PU) membrane with the active material 1,10-phenanthroline. The aim of this study was to investigate the influence of foreign ions and the Total Ionic Strength Adjustment Buffer (TISAB) on the response of the Al3+ ISE. The impact of foreign ions was evaluated by determining the selectivity coefficients (Kij) using the separate solution method. The measured solutions included the main ion Al3+ and the foreign ions Na+, K+, Li+ , Pb2+, Ca2+, Co2+, Cu2+, Ni2+, Cr3+, and Fe3+ over a concentration range of 1x10-9 – 1x10-4 M. The research results indicated that the presence of foreign ions did not affect the performance of the Al3+ ISE, as evidenced by Kij values < 1. The selectivity order of the Al3+ ISE was found to be Fe3+ > Cr3+ > Pb2+ > Cu2+ > Ni2+ > Co2+ > Ca2+ > Li+ > Na+ > K+. The influence of TISAB concentration on linearity, limit of detection (LOD), and limit of quantification (LOQ) were tested. The results showed high sensitivity at TISAB concentrations of 1x10-1, 1x10-2, 1x10-3, 1x10-4, and 1x10-5 were 18,50 ± 0,71, 18,52 ± 1,4, 18,18 ± 0,05, 18,89 ± 0,5, and 19,15 ± 0,27, respectively. The response of the Al3+ ISE measured without TISAB solution exhibited a shorter linear range of 10-4 – 10-9 M. After the addition of TISAB solution, the linear range extended to 10-4 – 10-10 M. Lower LOD and LOQ values were achieved with the addition of TISAB, and the coefficient of determination (≈ 1) indicated that the Al3+ ISE based on PU membrane exhibited good linearity towards Al3+ ions. Therefore, the optimal TISAB concentration obtained from this study was 1x10-5. Additionally, the Kij values of the PU membrane-based Al3+ ISE were determined at various concentrations of foreign ions including Na+, K+, Li+, Pb2+, Ca2+, Co2+, Cu2+, Ni2+, Cr3+, dan Fe3+.