Jika timah digunakan sebagai bahan pembungkus untuk makanan dan minuman, akan ada Sn yang terlarut dalam jumlah yang sangat kecil yaitu sekitar 0.06 ppm dalam makanan atau minuman tersebut. Penelitian ini bertujuan untuk menentukan kadar timah menggunakan metode spekrofotometri DRS UV-Vis berdasarkan reduksi dengan metilen biru oleh Sn dalam medium admisel γ- Al2O3/HDTMA-Br. Gamma-alumina diperoleh melalui kalsinasi (NH4)Al(SO4)2.12H2O pada suhu 900 °C selama 6 jam. Admisel γ- Al2O3/HDTMA-Br dipreparasi melalui adsorpsi surfaktan HDTMA-Br pada γ- alumina pada CAC (Critical Admicelle Concentration) optimum, nilai ini diperoleh dari kurva isoterm adsorpsi HDTMA-Br pada γ-alumina. Hasil penelitian menunjukkan pembentukan admisel γ-Al2O3/HDTMA-Br terjadi pada pada pH 10 dan konsentrasi HDTMA-Br 800 μM. Struktur kristal γ-Al2O3 dikarakterisasi melalui metode x-ray diffraction dan pembentukan admisel γ- Al2O3/HDTMA-Br dikarakterisasi dengan FT-IR. Penentuan kadar Sn2+ dengan metode ini berdasarkan pada reduksi metilen biru oleh SnCl2 dalam larutan HCl. Pengurangan warna metilen biru sebanding dengan konsentrasi Sn2+ dalam larutan¸ dengan asumsi bahwa semua Sn2+ dalam larutan teroksidasi oleh metilen biru dalam media admisel. Dalam penelitian ini, konsentrasi SnCl2 minimum yang mereduksi metilen biru adalah Sn 5.3 x 10-7 M.

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In case of tin (Sn) is used in the packaging material for food or beverage, a very small quantity of Sn will be dissolved in the food or drink around 0.06 ppm. This study is aimed to determine the Sn concentration using DRS UVVis Spectrophotometry method based on the reduction of methylene blue adsorption in γ-Al2O3/HDTMA-Br admicelle medium. γ-alumina was obtained calcination of (NH4)Al(SO4)2.12H2O at a temperature of 900 °C for 6 hours. γ-Al2O3/HDTMABr admicelle was prepared by adsorption of HDTMA-Br surfactant in γ-alumina at the optimum CAC (Critical Admicelle Concentration) value¸ which was obtained from the adsorption isotherm curve of HDTMA-Br surfactant on γ- alumina. The results showed that the formation of γ-Al2O3/HDTMA-Br admicelle optimum occurred at pH 10 and HDTMA-Br concentration of 800 μM. The crystal structure of γ-Al2O3 was characterized by x-ray diffraction method and the formation of γ-Al2O3/HDTMA-Br admicelle was characterized by FT-IR. The determination of Sn2+ was conducted based on the reduction of methylene blue by SnCl2 in HCl solution. The decolorization of methylene blue is equivalent with the Sn2+ concentration in solution¸ assumed that all Sn2+ in solution were oxidized by methylene blue in admicelle medium. In this study, the minimum concentration of SnCl2 was found Sn 5.3x 10-7 M.