BS EN 14107 Fat and oil derivatives - Fatty Acid Methyl Esters (FAME) - Determination of phosphorous content by inductively coupled plasma (ICP) emission spectrometry
5 Reagents
Use only reagents of recognized analytical grade, unless otherwise specified.
5.1 Recommendation for washing glassware: in order to avoid phosphorus pollution due to the phosphates contained in the detergents used for washing the glassware, rinse the latter at least twice with an approximate 5 mol/l solution of hydrochloric acid. Next rinse with distilled water then dry.
5.2 Xylene (mixture of isomers).
WARNING Inflammable and noxious.
5.3 Stock oil 75 (viscosity 75 mm2/s).
5.4 Stabilizer, optional, to stabilise the stock solution.
5.5 Phosphorus organic standard, 1000 mg/kg.
NOTE Other suitable commercially available standard can also be used.
5.6 Phosphorus, intermediate dilution solution for preparation of the set of calibration solutions:
100 mg/l phosphorus solution containing 0.6 % of stabilizer (5.4): weigh to within 0.001 g approximately 5 g of the phosphorus solution (5.5) in a 50 ml volumetric flask. Add approximately 0,3 g of stabilizer (5.4), dilute to the mark with xylene and homogenise the solution. The exact titre of this solution will be calculated and subsequently used for the standards. This solution may be kept during one month, if the stabilizer (5.4) is used.
In case stabilizer is not used, the intermediate dilution solution of phosphorus cannot be kept.
NOTE The volumetric flasks can be replaced by disposable non calibrated flasks; in this case, the dilutions of the samples are prepared and expressed in mass/mass instead of mass/volume.
6 Apparatus
6.1 An inductively coupled plasma emission spectrometer equipped with the following elements:
6.1.1 A quartz torch.
6.1.2 A nebulizer (device which transforms the solution into an aerosol).
6.1.3 A peristaltic pump is necessary. The pumping speed shall be between 0.5 ml/min and 3 ml/min inclusive. Viton flow rate tubes are recommended in order to withstand the xylene.
6.2 Balance, with an accuracy of 0.1 mg.
6.3 Glassware: 25 ml and 50 ml volumetric flasks.
6.4 Graduated pipettes, of 1 ml and 5 ml capacity or Variable volume automatic pipettes fitted with disposable polypropylene tips.
7 Sampling
It is important that 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 European Standard. A recommended sampling method is given in EN ISO 5555.
8 Preparation of test portion
Prepare the test portion in accordance with EN ISO 661. The test portion shall not be heated and/or filtered.
