Palm Kernel Oil
Elaeis guineensis seed oil [8023-79-8].
» Palm Kernel Oil is the refined fixed oil obtained from the kernel of the fruit of the oil palm Elaeis guineensis Jacq. (Fam. Arecaceae). It may contain suitable antioxidants.
Packaging and storage Preserve in well-closed containers. Do not store above 45.
Labeling Label it to indicate the name and quantity of any added antioxidants.
A: It meets the requirements of the test for Fatty acid composition.
B: It meets the requirements of the test for Melting range.
Melting range 741: between 27 and 29.
Acid value 401: not more than 2.0.
Peroxide value 401: not more than 10.0.
Unsaponifiable matter 401: not more than 1.5%.
Fatty acid composition Palm Kernel Oil exhibits the following composition profile of fatty acids, as determined in the section Fatty Acid Composition under Fats and Fixed Oils 401:
Water, Method I 921: not more than 0.1%, 50 mL of chloroform being used instead of 35 to 40 mL of methanol as the solvent.
Limit of lead [noteFor this test, use reagent-grade chemicals with as low a lead content as is practicable, as well as high-purity water and gases. Before use in this analysis, rinse all glassware and plasticware twice with diluted nitric acid and twice with diluted hydrochloric acid, and then rinse them thoroughly with Purified Water.]
Hydrogen peroxidenitric acid solution Dissolve equal volumes of 10% hydrogen peroxide and diluted nitric acid. [noteUse caution.]
Lead nitrate stock solution Dissolve 159.8 mg of lead nitrate in 100 mL of Hydrogen peroxidenitric acid solution. Dilute with Hydrogen peroxidenitric acid solution to 1000 mL, and mix. Prepare and store this solution in glass containers that are free from lead salts. Each mL of this solution contains the equivalent of 100 µg of lead.
Standard lead solution On the day of use, dilute 10.0 mL of Lead nitrate stock solution with Hydrogen peroxidenitric acid solution to 100.0 mL and mix. Each mL of Standard lead solution contains the equivalent of 10 µg of lead.
Butanolnitric acid solution Slowly add 50 mL of nitric acid to approximately 500 mL of butanol contained in a 1000-mL volumetric flask. Dilute with butanol to volume, and mix.
Standard solutions Into five separate 100-mL volumetric flasks, pipet 0.2, 0.5, 1, 2, and 5 mL, respectively, of Standard lead solution, dilute with Butanolnitric acid solution to volume, and mix. The Standard solutions contain, respectively, 0.02, 0.05, 0.1, 0.2, and 0.5 µg of lead per mL.
Test solution [CautionPerform this procedure in a fume hood, and wear safety glasses. ] Transfer 1.0 g of Oil, accurately weighed, into a large test tube. Add 1 mL of nitric acid. Place the test tube in a rack in a boiling water bath. As soon as the rusty tint is gone, add 1 mL of 30 percent hydrogen peroxide dropwise to avoid a vigorous reaction, and wait for bubbles to form. Stir with an acid-washed plastic spatula if necessary. Remove the test tube from the water bath, and allow it to cool. Transfer the solution into a 10-mL volumetric flask, dilute with Butanolnitric acid solution to volume, and mix.
Tungsten solution Transfer 0.1 g of tungstic acid and 5 g of sodium hydroxide pellets into a 50-mL plastic bottle. Add 5.0 mL of water, and mix. Heat the mixture in a hot water bath until complete solution is achieved. Cool, and store at room temperature.
Procedure Place the graphite tube in the furnace. Inject a 20-µL aliquot of the Tungsten solution into the graphite tube, using an argon flow rate of 300 mL per minute. Maintain the drying temperature at 110 for 20 seconds, the ashing temperature at 700 to 900 for 20 seconds, and with the argon flow stopped, the atomization temperature at 2700 for 10 seconds; repeat this procedure once more using a second 20-µL aliquot of the Tungsten solution. Clean the quartz windows. [noteThe sample injection technique is the most crucial step in controlling the precision of the analysis; the volume of each of the Standard solutions and the Test solution must remain constant. Rinse the microliter pipet tip three times with either the Standard solutions or the Test solution before injection. Use a fresh pipet tip for each injection, and start the atomization process immediately after injecting the Standard solutions and the Test solution. Between injections, flush the graphite tube of any residual lead by purging at a high temperature as recommended by the manufacturer.]
Concomitantly determine the absorbances of the five Standard solutions and the Test solution, at the lead emission line at 283.3 nm, with a suitable graphite furnace atomic absorption spectrophotometer (see Spectrophotometry and Light-scattering 851) equipped with a lead hollow-cathode lamp by atomizing the equal volumes (20 µL) of the solutions with an argon flow rate of 300 mL per minute. Maintain the drying temperature of the furnace at 110 for 30 seconds after a 20-second ramp time and a 10-second hold time; the ashing temperature at 700 for 42 seconds after a 20-second ramp time and a 22-second hold time; and the atomization temperature at 2300 for 7 seconds with the argon flow stopped. Plot the absorbance of each of the Standard solutions, compensated for background correction, versus its content of lead, in µg per mL, and draw the best straight line fitting the five points. From this plot, determine the concentration, C, in µg per mL, of lead in the Test solution. Calculate the quantity, in µg per g, of lead in the Oil taken by the formula:
10C / W
in which W is the weight, in g, of the Oil taken to prepare the Test solution: not more than 0.1 µg of lead per g is found.