CHEM/MBIO2360 Experiment 7. Iodine Number Determination of Triacylglycerols 2. Iodine number calculation of Olive Oil a) Volume of sodium thiosulfate = 9.9 mL – 0.0 mL = 9.9 mL = 0.0099L b) Moles of Sodium thiosulfate n = CV = (0.05 M)(0.0099L) = 4.95 × 10−4 mol mole of Control Volume of control = 36.4 mL – 11.0 mL = 25.4 mL = 0.0254 L n = CV = (0.05 M)(0.0254 L) = 1.27 × 10−3 mol c) Difference between control and sample in terms of mole of sodium thiosulfate = 1.27 × 10−3 mol - 4.95 × 10−4 mol = 7.75 × 10−4 mol d) Gram of Iodine4 = 7.75 × 10−4 mol × 126.90 e) π πππ = 0.0983 g of Iodine Iodine number 0.0983 π ππ πΌπππππ 0.1 π ππ πππππ = π₯ ππ ππππππ 100π ππ πππππ x = 98.3 g Iodine number of Oil sample = 98.3 Iodine number calculation of Butter a) Volume of sodium thiosulfate = 31.5 mL – 9.9 mL = 21.6 mL = 0.0216L b) Moles of Sodium thiosulfate n = CV = (0.05 M)(0.0216L) = 1.08 × 10−3 mol c) Difference between control and sample in terms of mole of sodium thiosulfate = 1.27 × 10−3 mol - 1.08 × 10−3 mol = 1.90 × 10−4 mol d) Gram of Iodine4 = 1.90 × 10−4 mol × 126.90 e) π πππ Iodine number 0.0241 π ππ πΌπππππ 0.1 π ππ πππππ = π₯ ππ ππππππ 100π ππ πππππ x = 24.1g Iodine number of Fat sample = 24.1 = 0.0241 g of Iodine Table 1. Iodine number of Olive oil(Oil) and butter(Fat) sample. Oila Fatb 3 Published Iodine Number 80-88 26-40 Experimented Iodine Number 98.3 24.1 a Sample consist 0.1g of Olive oil b sample consists 0.1g of butter. Solution contains cyclohexane, 1%(w/v) starch solution 10%(w/v) as titration indicator, KI solution and Wikis Reagent (1.6% (w/v) ICl in acetic acid) and titrated with 50.0 mM sodium thiosulfate. As we compared our experimental values to published values, they are close enough to be consider as ideal experimental results. However, since it cannot be in the exact value range, we can assume that some experimental error might affect to our result.3 Abundant lipids consist fatty acid chain and glycerol backbone. Fatty acid can be saturated and unsaturated by existence of double carbon-carbon bond.2 Saturated lipid has no double bond whether unsaturated lipid has various number of double bonds. This unsaturated double carbon-carbon bonds make the lipid as liquid in room temperature while saturated lipids keep as in solid. Reacting with iodine can represent the amount of double bond in fatty acid where can react with Iodine. So If the Iodine number is high, the number of double bond in fatty acid tail also high relatively. According to the results from this experiment, Oil sample has more iodine value than the Fat sample. Therefore, the Oil is more unsaturated with containing more double bonds than the Fat sample. As we compare that physical observation of our sample, Oil is more unsaturated lipid and has as liquid state at room temperature which also related with lower melting point. On the other hand, Fat sample was in solid which means it contains highly saturated fatty acid. Those fact contributes to fat lipid can have high melting point so it can keep solid state at room temperature. Therefore, Iodine values are consistent with our physical properties/state observation of samples lipid.1 Reference (1) Nichols, E.R. (2018) Biochemistry I: Biomolecules and an Introduction to Metabolic Energy Lab Manual. (2) Mark, B., McKenna, S. (2018) Biochemistry I Course Pack, Hayden-mcneil, Macmillan Learning, United States of America (3) Iodine value. (2018, November 14). Retrieved November 22, 2018, from https://en.wikipedia.org/wiki/Iodine_value (4) Molar mass of I2. (n.d.). Retrieved November 22, 2018, from https://www.webqc.org/molecular-weight-of-I2.html