ANALISIS NITRIT DAN NITRAT BEBAS DALAM SUSU FORMULA BAYI DENGAN MENGGUNAKAN METODE SPEKTROFOTOMETRI UV VIS

OKTAVIAN IRA W, Drs. Roto, M.Eng., Ph.D

2013 | Skripsi | KIMIA

Telah dilakukan analisis nitrit dan nitrat dalam susu formula bayi dengan metode spektrofotometri UV-Vis. Analisis diawali dengan menentukan beberapa parameter analitik, kemudian analisis nitrat dan nitrit di dalam susu. Preparasi sampel dilakukan dengan melarutkan susu formula dalam akuabides hangat (40 oC) kemudian disaring sebanyak 2 kali dan dianalisis. Sampel ditambahkan larutan brusin dan asam sulfat sehingga berwarna kuning. Analisis awal diperoleh data mengenai konsentrasi nitrat dalam susu formula. Analisis selanjutnya dengan pemberian H2O2 pada larutan sampel, dari analisis ini diperoleh data mengenai konsentrasi total nitrat dan nitrit. Konsentrasi nitrit diperoleh dari selisih antara analisis sebelum dan setelah penambahan H2O2. Metode validasi dilakukan dengan penambahan larutan standar ke dalam sampel. Hasil validasi data diperoleh persen perolehan kembali antara 90,7-95,7% pada penambahan NaNO3 dengan konsentrasi antara 0–20 ppm. Pengukuran limit deteksi nitrat dilakukan dengan dua metode yaitu dengan larutan blangko dan standar deviasi. Batas deteksi dengan metode standar deviasi memberikan hasil sebesar 1,809 ppm dan batas deteksi dengan metode larutan blangko sebesar 1,650 ppm. Konsentrasi nitrit dan nitrat di dalam susu formula lebih besar dibandingkan susu segar. Semakin lama penyimpanan susu, konsentrasi nitrit di dalam susu semakin bertambah. Susu formula yang disimpan tidak terlalu rapat menyebabkan kadar nitrat dan nitritnya juga besar, karena oksigen di dalam udara dapat bereaksi dengan nitrit.

Analysis of free nitrite and nitrate in baby formula by spectrophotometry UV-Vis have been carried out. The first step was determining the analytical parameters. The second and third steps were determining nitrate and nitrite content. The milk powder was suspendend in warm distilled water (40 oC) then filtered twice to obtained the supernatant for analysis. The brucine solution was added to supernatant to make a yellow solution to determine nitrate content. The nitrite ion was oxidized with hydrogen peroxide before further analysis. The nitrite content is the difference between the one with and without addition of hydrogen peroxide. The validation was determined by standard addition method. The results showed that percent recovery was laid between 90.7–95.7% for 0–20 ppm nitrate. The limit of detection (LOD) was determined by two methods, which were by blank solution and by standard of deviation methods. The LOD from standard of deviation was 1.809 ppm and that of blank solution was 1.650 ppm. Fresh milk had lower nitrite and nitrat content than that of baby formula. It was found that the longer the storage time, the higher the concentration of nitrite. Baby formula, which were stored in open container, contained the nitrite and nitrate higher than that stored in closed container. The oxygen in the air could react with nitrite faster.

Kata Kunci : nitrit, nitrat, susu, susu formula