PENGUKURAN SIFAT POLARISASI BERBAGAI MINYAK NABATI MENGGUNAKAN LAMPU IR DAN LASER HE-NE

U Kaltsum, KS Firdaussi

Abstract


Penelitian ini bertujuan untuk menguji sifat polarisasi berbagai minyak nabati (minyak sawit, minyak kedelai, minyak zaitun, VCO, minyak curah, dan jelantah) dengan variasi keadaan baru dan kadaluwarsa, menggunakan lampu IR dan laser He-Ne. Pengujian dilakukan dengan menempatkan minyak nabati diantara polarisator dan analisator. Hasil penelitian pada kedua sumber cahaya menunjukkan pola yang hampir sama. Minyak zaitun dan VCO memiliki perubahan sudut polarisasi alami kecil, sedangkan minyak sawit, kedelai, jelantah, dan curah memiliki perubahan sudut polarisasi alami besar. Besarnya perubahan sudut polarisasi minyak kadaluwarsa lebih besar dibanding minyak baru. Perubahan sudut polarisasi sebanding dengan jumlah radikal bebas (ALB, peroksida) dan molekul asimetri (asam lemak jenuh, molekul rantai panjang). Meskipun pola yang dihasilkan oleh kedua sumber cahaya sama, namun lampu IR memberikan nilai perubahan sudut polarisasi yang lebih tinggi dari laser He-Ne. Hal ini dimungkinkan karena daya lampu IR lebih besar dari He-Ne, sehingga energi yang dihasilkan lampu IR lebih tinggi dan perubahan sudut polarisasinya lebih besar.

This research based on previous research that using IR lamp (250 watt) and He-Ne laser (1 mW) on a mixture of palm oil and animal oil. Both of light source were used again to measure polarization properties of various vegetable oils (palm oil, soybean oil, olive oil, VCO, rainfall oil and used cooking oil) with a variety of new and expired. The tools used were a set polarization, IR lamp, He-Ne laser, and power supply. The experiment was done by placing vegetable oil between the polarizer and analyzers. The result showed both of light sources had similar pattern; polarization changes of olive oil and the VCO were small, while polarization changes of palm oil, soybean oil, used cooking oil, and rainfall were high. Polarization change of expired oil was higher than new oil. The value of polarization change was proportional to free radicals (FFA, peroxide) and asymmetry molecular (saturated fatty acids, long chain molecules). Although the patterns resulted by two light sources were same, IR lamp provide polarization change higher than He-Ne laser. This might be due to the power of IR light was greater than the power of He-Ne laser.


Keywords


IR lamp; He-Ne laser; vegetable oil; polarization

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References


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