ISO 662:2016 download.Animal and vegetable fats and oils – Determination of moisture and volatile matter content.
1 Scope
ISO 662 specifies two methods For the determination, by drying, of the moisture and volatile matter content of animal or vegetable fats and oils:
— method A, using a sand bath or hotplate;
— method B, using a drying oven,
Method A Is applicable to all fats and oils.
Method B is applicable only to non-drying fats and oils with an acid value less than 4. Under no circumstances are buric oils be analysed by this method.
Milk and nitik products (or fat obtained from milk and milk products) are excluded from the Scope of this International Standard.
2 Normative reference
The following documents, in whole or in part, are normatively relerenced in ISO 662 and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the btest edition of the referenced document (including any amendments) applies.
ISO 661. Animal and vegetable fats and oils — Preparation of test wmple
3 Terms and definitions
For the purposes of this document, the following terms and delinitions apply.
moisture and volatile matter content
loss in mass undergone by the product on heating at 103°C ± 2 °C under the conditions specified in ISO 662
Note I to entry: It is expressed as a percentage by mass
4 PrincIple
Heating a test portion at 103°C ± 2°C until moisture and volatile substances are completely eliminated. and determination of the loss in mass.
S Sampling
Sampling is not part of the method specified in this International Standard. A recommended sampling method is given In ISO 5555.
it Is Important that the laboratory receives a sample which is truly representative and has not been damaged or changed during transport or storage.
6 Preparation of test sample
Prepare the test sample in accordance with ISO 661.
7 Method A
7.1 Apparatus
Usual laboratory apparatus and, in particular, the following.
7.1.1 Analytical balance, capable olweighing to the nearest 0,001 g,
7.12 DIsh, made of porcelain or glass. 80 mm to 90 mm In diameter, about 30 mm deep, with a flat bottom.
7,13 Thermometer, graduated from about 80 °C to at least 110 ℃. about 100 mm long, with a reinforced tip and with an expansion chamber at its upper end.
7.1.4 Sand bath or electric hotplate.
7.1.5 Desiccator, containing an efficient desiccant,
7.2 Procedure
72.1 Test portion
Weigh, to the nearest 0,001 g. approximately 20 g of the test sample (CLanse6) into the dish (7.12) which has been previously dried and then weighed together with the thermometer (7.1.3).
7.2,2 Determination
Heat the dish containing the test portion (7.2.1) on the sand bath or electric hotplate (7.1.4). allowing the temperature to rise at a rate of about 10 ℃/mb up to 90 ℃. and stirring constantly with the thermometer.
Reduce the rate of heating, observing the rate at which bubbles rise from the bottom of the dish, and allow the temperature to rise to 103 ℃ * 2 C. Do not heat above 105 “C. Continue to stir, scraping the bottom of the dish until all evolution of bubbles has ceased,
To ensure the removal of all moisture, repeat the heating to 103 °C ± 2 C several times, cooling to 95 “C between the heating periods. Then allow the dish and thermometer to cool in the desiccator (7.1.5) to room temperature and weigh to the nearest 0,001 g. Repeat this operation until the difference between the results of two successive weighings does not exceed 2 mg.
7.2.3 Number of determinations
Carry out two determinations on test portions taken from the same test sample (CLause).
8 Method B
8.1 Apparatus
Usual laboratory apparatus and, In particular, the following.
8.1.1 Analytical balance, capable of weighing to the nearest 0,001 g.
8.1.2 Glass vessel, approximately 50 mm in diameter and 30mm tall, with a flat bottom.
8.1.3 Electric drying oven, capable of being maintained at 103 Ct 2 °C.
8.1.4 Desiccator. containing an efficient desiccant.
8.2 Procedure
8.2.1 Test portion
Weigh, to the nearest 0,001 it. approximately 5 g or 10 g of the test sample (Clause 6), according w the expected moisture and volatile matter content, into the vessel t8LZ) which has been previously dried and then weighed.
8.2.2 Determination
Keep the vessel containing the test portion W2d) for 1 h In the drying oven (8.1.3). set at 103 °C. Allow to cool to roam temperature in the desiccator (8.1.4) and then weigh to the nearest 0,00 1 g. Repeat the operations of heating, cooling and weighing, but use successive periods in the oven of 30 mm each, until the loss in mass between two successive weighings does not exceed 2 mg or 4 mg, according to the mass of the test portion.
NOTE An increase of mass of the test portion after repeated heating indLcates that autoxidatlon of the tat or oil has occurred. In this case, take for calculation of the result the smallest mass recorded or, preferably, use method A
8.2,3 Number of determinations
Carry out two determinations on test portions taken from the same test sample (C1aue6).
9 Expression of results
The moisture and volatile matter content, w, expressed as a percentage by mass, is equal to rn-rn
x100’,f (1)
m1 — m0
where
m is the mass, in grams, of the dish and the thermometer (72,1). or of the glass vessel (8.2.1):
rn is the mass, in grams, of the dish, thermometer and test portion (72.1), or of the vessel and Lest portion (8.2.1) before heating:
m2 Is the mass, in grams, of the dish, thermometer and residue (2.22), or of the vessel and resi’ due (822) after heating.
Take as the result the arithmetic mean of the two determinations, provided that the requirement for repeatability (see 1Q2) is satisfied.
Report the result to the second decimal place.
10 PrecisIon
10.1 Interlaboratory test
Details ofan Interlaboratory test on the precision of the method are summarized In AnzuutA. The values derived from this interlaboratory test may not be applicable to concentration ranges and matrices other than those given.
10.2 Repeatability
The absolute difference between two independent single test results, obtained using the same method on identical test material in the same laboratory by the same operator using the same equipment within a short interval of time, will in not more than 5 % or cases be greater than 0,03 g of moisture and volatile matter per 100 g of sample For a moisture and volatile matter content of about 0,3 %.
10.3 ReproducibIlity
The absolute difference between two single test results, obtained using the same method on identical test material in different laboratories with different operators using different equipment, will in not more than 5 % of cases be greater than 0.15 g of moisture and vobtile matter per 100 g of sample for a moisture and volatile matter content of about 0.3 %.
11 Test report
The test report shall specify the following:
— all information necessary for the complete identification of the sample:
— the sampling method used, if known;
— the test method used, with a reference to ISO 662, I.e. ISO 662;
— all operating details not specified in ISO 662, or regarded as optional, together with details of any incidents which may have influenced the test result(s);
— the test result(s) obtained;
— If the repeatability has been checked, the final quoted result obtained.