BS EN ISO 7328-2000 Milk based edible ices and ice mixes De termination offat content- Gravimetric method ( Reference method).
5 Reagents
Use only reagents of recognized analytical grade, unless otherwise speifed, and ditliled or demineralized water or water of equivalent purity.
The reagents shall leave mo appreciable residue when the detrmination is arried out by the mothod specifid (see 9.22)
5.1 Ammonia slution, containing a mass facton of NH3 of apoximately 25 % (P20 = 910gM.
NOTE H ammonia solution of this concentration is not awailable, a more concentrated solution of knowm concentrabion may be used (5e0 9.42).
5.2 Ethanol (C2HOH), or ethanol denatured by methanol, containing a volume fraction of ethanol of at least 94 %(See A.5.)
5.3 Congo red solution
Dissove 1 g of Congo red in water in a 100 ml one mark volumetric flask (6.16) Dilute t0 the mark with water.
NOTE The use of this soluton, which alows the inertace betwee the solvent and aqueous layers 10 be see more clearly. Is optional (8ee 9.4.4). Other aqueous colour soluions may be used provided that they do not atect the result of the determination.
5.4 Diethyl ether (C2HgOCzH5). free from perodes (see A.3)。containing no more than 2 mgkg of antoxidants, and complying with the requirements tor the blank test (see 9.22, A.1 and A4).
NOTE The u50 of digtyl ther could lhad加hazardous Sualfons. Due to expected chanpes in satoty rgulationsn studies are ongoing to replace dietiyl ether by another reagent provided that i does not afet the end Tesut of the determinaton.
5.5 Light petroleum, with any boiling range between 30 °C and 60 °C or, as equivalent, pentane (CHj[CH2]sCHa) with a blling point of 36 C and complying with the requiroments for the blank tost (00 9.22, A.1 and A4).
NOTE The use of pentane ts rcommended because of its higher purity and constant qually.
5.6 Mixed solvent
Shortly belore use, mix equal volumes of dethyl ether (5 4) and ight petroleum (5.5).
6 Apparatus
WARNING一Since the determination involves the use of volatile flammable solvents, all electrical apparatus employed shall comply with legislation relating to the hazards in using such solvents.
Usual laboratory equipment and, in particular, the ollowing.
6.1 Analytical balance, capable of weighing to the nearest 1 mg. with a readability of0,1 mg.
6.2 Cntriluge, capable of holding the tat extracion lasks or tubes (6.6) and capable ofl spinning at a rlttonal frequency of 500 min-1 to 600 min-1 to produce a radial acceleration of 80g to 90 g at the outer end of the flasks or tubes.
NOTE The use of the entrunge is oponal but ecommended (see 94.7
6.3 illation or evaporation apparatus, tor ditling the solvents and ohanol from the bolling or conical fasks,
or evaporating from beakers and dishes (s00 9.4.14) at a temperature not exceeding 100 C.BS EN ISO 7328 pdf download.