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Abstrak :
Nanozeolite synthesis was carried out through seeding method, in which the seed was Y zeolite (member of faujasite, FAU, family) using tetraethyl orto silicate (TEOS) as silica source, and aluminium isopropoxide Al[(CH3)2CHO)]3 as aluminum source, and tetramethylammoniumhydroxide (TMAOH) as template, under hydrothermal condition. The seeds then were grown on glassy carbon (GC) sheet, that prior being used was modified, using layer by layer (LbL) technique, with three layers of polyelectrolytes: Poly(diallyldimethylammoniumchloride), PDDA; Poly-4-sodium-styrenesulfonate, PSS; and PDDA again. The seeded GC sheet then was immersed into colloidal suspension with molar composition as follow: 14Na2O: Al2O3: 10SiO2: 798H2O: 3Na2SO4 and the pH of the suspension was kept at 9,0 before was treated hydrothermally for 20 hours at 100oC. The variation on number of seed layers on GC (1, 2 and 3 layers), observed by SEM, showed that homogenous structure and crystal size was obtained with 1 layer of seeds applied on the surface of glassy carbon. When more layers of seeds applied, the agregation and intergrowth of zeolite crystals in the thin film of zeolite became more visible. XRD pattern of the as-prepared thin film zeolite indicates that the zeolite has nanoparticle structure. Furthermore, the pattern of glassy carbon predominated the XRD pattern and covered the pattern of Y-zeolite. On the other hand, XRD of as prepared bulk Y-zeolite shows structure of FAU framework.

Abstrak :
Pengembangan Strip Test Immunokromatografi untuk Pendeteksi Melamine Secara Selektif dan Kuantitatif. Strip test berbasis imunokromatografi berdasarkan reaksi pembentukan kompleks antigen-antibodi (melamin-antimelamin) dikembangkan untuk mendeteksi melamin secara kuantitatif. Nanopartikel emas (AuNP) digunakan sebagai label pada antibodi untuk membentuk antibodi berlabel AuNP yang kemudian berfungsi sebagai biosensor. Kuantifikasi melamin diperoleh dengan menentukan konsentrasi AuNP menggunakan teknik anodic stripping voltammetry. Boron-doped diamond digunakan sebagai elektroda kerja. Dengan volume sampel 100 μL dan waktu imunoreaksi 7 menit, strip test menghasilkan kurva linier pada kisaran konsentrasi 0?0,6 mg/L dengan batas deteksi 0.1 mg/L dan RSD ~5%. Selain itu hasil negatif diperoleh ketika strip test diaplikasikan pada sampel yang mengandung asam sianurat dan urea, hal tersebut mengindikasikan bahwa strip test yang dikembangkan dapat digunakan sebagai pendeteksi melamin secara selektif dan kuantitatif.

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An immunochromatographic strip test based on the complex reaction of antigen-antibody (melamine-antimelamine) was developed for quantitative detection of melamine. Gold nanoparticles (AuNP) were used to form AuNP-labeled antibody, which then acted as a biosensor. Melamine quantification was performed by the determination of AuNP using anodic stripping voltammetry technique with a boron-doped diamond as the working electrode. With sample volume of 100 μL and immunoreaction time of 7 min, the developed immunochromatographic strip test produced a linear calibration curve for melamine concentration range of 0?0.6 mg/L, with detection limit of 0.1 mg/L and RSD of ~5%. Furthermore, negative results were obtained for samples containing cyanuric acid and urea, indicating that the developed immunochromatographic strip test has potential for selective and quantitative detection of melamine.