BS EN ISO 6321:2021 pdf download.Animal and vegetable fats and oils — Determination of melting point in open capillary tubes — Slip point.
5 Apparatus Usual laboratory apparatus and, in particular, the following.
5.1 Capillary tubes, having uniform walls and which are open at both ends, of internal diameter 0,9 mm to 1,2 mm, external diameter 1,2 mm to 1,6 mm, wall thickness 0,15 mm to 0,30 mm and length 50 mm to 70 mm 1) . Before use, clean the tubes thoroughly by washing them successively with a mixture of chromic acid, water and acetone or an alternative suitable cleaning solution, for example, hydrogen peroxide can be used. Dry the capillary tubes in an oven. However, it is recommended that new tubes are used.
5.2 Thermometer, graduated in divisions of 0,1 °C, calibrated over the range of melting points expected.
5.3 Stirrer, electrical.
5.4 Cooling bath, filled with brine or other non-freezing liquid, thermostatically maintained at a temperature of −10 °C to −12 °C, or filled with a mixture of flaked ice and salt (in the proportions 2 to 1 by mass) at a temperature of −10 °C to −12 °C.
5.5 Heating apparatus, consisting of the following elements: a) water jacket, made of glass, provided with inlet and outlet tubes, and having the shape and dimensions shown in Figure 1; b) water heater, capable of delivering a slow stream of water, the temperature of which can be controlled to increase at a rate of between 0,5 °C/min and 4 °C/min, through the water jacket [5.5 a)]. An example of a suitable heating apparatus is shown in Figure 2. Other types of heating apparatus, such as a water bath with magnetic stirrer, capable of being controlled to produce the specified temperature rise [5.5 b)], may also be used.
6 Sampling It is important the laboratory receive a sample which is truly representative and has not been damaged or changed during transport or storage. Sampling is not part of the method specified in this document. A recommended sampling method is given in ISO 5555 [1] .
7 Preparation of test sample Prepare the test sample in accordance with ISO 661.
8 Procedure
8.1 Preparation of the capillary tubes for method A Melt a portion of the test sample as rapidly as possible to at least 5 °C, but not more than 10 °C, above the temperature at which it is completely melted. Dip two capillary tubes (5.1) into the melted test sample until columns of fat 10 mm ± 2 mm long are obtained. Immediately after filling the tubes, wipe them quickly with absorbent tissue to remove any fat adhering to the outer surfaces of the tubes. Immediately place the filled capillary tubes for a few seconds against a beaker filled with ice so that the fat solidifies. Place the tubes in the cooling bath (5.4) for 5 min. Continue in accordance with 8.3.
8.2 Preparation of the capillary tubes for method B Melt a portion of the test sample as rapidly as possible to at least 5 °C, but not more than 10 °C, above the temperature at which it is completely melted. Cool the melted test sample, with occasional stirring, until its temperature is 32 °C to 34 °C and then stir continuously with the stirrer (5.3), allowing the fat to cool until the first signs of cloudiness appear. Continue stirring by hand until the fat has a pasty consistency and then transfer the fat to a 100 ml beaker at 17 °C ± 2 °C. Store the fat at this temperature for a minimum of 24 h.BS EN ISO 6321 pdf download.