AOCS OFFICIAL METHOD CD 3D-63 PDF

Methods. Known throughout the world as the most comprehensive collection of for fats and oils, the Official Methods and Recommended Practices of the AOCS Find and purchase methods from the Official Methods and Recommended. cation of the AOCS Cd 3d method, through a statistical . Methods. AOCS Cd 3d Official Method [8]. The acid number in oils and fats is determined. ufacturing, Kyoto, Japan) according to the AOCS Official. Method Cd 3d [23]. All AV analysis results were expressed as mg KOH/g oil.

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An ultrasonic bath was used to degasify solvents and solutions.

Considering the above observations, the green method developed in this work can be proposed for the routine determination of the acid number of oils and fats. It was observed in the present work, that after about 10 titrations, it is advisable to keep the electrode immersed in a 0. April 4, Published online: In order to verify the accuracy of the potentiometric procedure developed with respect to the AOCS Cd 3d and to the two other applied methods, a statistical weighted linear regression procedure was used.

Rapid preventive rehydration 1 min is enough to maintain the membrane of the electrode in good conditions. Distilled water was mehhod from a glass distiller.

The acid number is calculated using equation 1. The electrodes were calibrated as usual with aqueous buffer solutions of pH 7. The solutions of the bases were stored in alkaline resistant bottles. How to cite this article. C is the concentration of the titrant solution mol L -1and m is the mass of the sample g. The acid number is calculated using equation 1 where A is the titrant solution volume mL used in the titration of the sample, B is the titrant solution volume mL used in titration of the blank.

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aocs official method cd 3d pdf – PDF Files

The acid number of the 75 mL of solvent blank value must be obtained by a similar titration. Solutions of sodium hydroxide and of potassium hydroxide were prepared by dissolving adequate masses of the bases in water. Potentiometrically titrate with 0. No evidence for systematic differences was observed. Therefore, the present work has as objective to apply potentiometric detection to the titrimetric method aiming at low cost, operational simplicity and, especially, as environmentally friendly procedure.

AOCS Cd 3d official method 28 The acid number of oils and fats is determined through the titration of the sample with a standardized 0. The green potentiometric method for the determination of the acid number of oils and fats herein proposed furnishes similar but more accurate and precise results to those obtained by the AOCS Cd 3d and by the ABNT-NBR methods that use organic solvents, such as toluene, and as titrant a KOH solution in isopropyl alcohol.

A Metrohm Solvotrode, 3.

aocs official method cd 3d-63 pdf

According to this method, a quantity of the sample, which varies with its acidity, is dissolved in mL of a solvent that is a 1: This can be attributed to the fact that it is more difficult to determine the end point of the titration with the official method than in the other cases.

The potentiometric titration curves obtained for the oils and for swine lard are quite similar to those seen in Figure 1and therefore, the end point is easily determined. Reagents, solutions and solvents. Despite the fact that the potentiometric methods can be more easily applied, in comparison to the visual method, as they do not depend on the color of the sample, in presence of organic solvents, the glass membrane of the electrode is dehydrated, a fact that results in instability of the measured electric potential.

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High aocss mean loss of money as the rating of the product decreases. Nova32AOCS Cd 3d official method Conclusion The green potentiometric method for the determination of the acid number of oils and fats herein proposed furnishes similar but more accurate and precise results to those obtained by the AOCS Cd 3d and by the Pfficial methods that use organic solvents, such as toluene, and as titrant a KOH solution in isopropyl alcohol.

This situation not only reduces the time of the analysis, but also minimizes the possible effect of dehydration of the electrode as it remains for a shorter period in contact with the 1: Analytical procedures Green potentiometric method Weight with at mtehod 0. It should be noted that this method was originally proposed for the determination of the acid number of mineral oils and of biodiesel. Weigh the sample directly into a mL tall form beaker.

A green potentiometric method for determination of the acid number of oils and fats

Soy, corn, canola, sunflower, linseed and castor oils and swine lard used in the present study were purchased at local markets. Nova28Recently a green visual titrimetric method was presented for the determination of the acid number of oils and fats, using as titrant an aqueous 0.

The sample is dissolved in a water-ethanol mixture 1: For linseed, no statistical concordance was observed. The potentiometric method herein proposed was performed point-by-point and also using an automatic titrator in order to obtain the acid number of the solvents. The membrane must be frequently rehydrated or the electrode can be irreversibly damaged.

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