BS EN 13131 pdf free download
BS EN 13131 pdf free download.Methods of test for petroleum and its products.
3 Principle The sample is diluted with an organic solvent, the solution aspirated into the flame of an atomic absorption spectrometer, and the absorbance of the characteristic radiation of nickel or vanadium is measured. An acetylene/air flame is used for nickel and a nitrous oxide/acetylene flame for vanadium. Calibration curves are obtained from measurements on calibration solutions of fuels with a known content of nickel and/or vanadium in the same solvent or from measurements on calibration solutions of organometallic compounds in the same solvent. 4 Reagents and materials Use only reagents of recognized analytical grade. 4.1 Xylene, isomer mixture. 4.2 Propan-2-ol. 4.3 Standard fuel oils, or organometallic standards in oil, with known contents of nickel and/or vanadium. 4.4 Base oil, free of nickel and vanadium.5 Apparatus Usual laboratory apparatus and glassware, together with the following. 5.1 Flame atomic absorption spectrometer, suitable for measurements at wavelengths of 352,5 nm (for nickel) and 318,4 nm (for vanadium), fitted with a gas burner with provisions for the aspiration of organic liquids into the flame, and with burner heads capable of burning air-acetylene and nitrous oxide-acetylene mixtures. NOTE For some spectrometers it may be better to use a wavelength of 232,0 nm for nickel. At this wavelength, there may be some nonlinearity. The precision data quoted in clause 10 for nickel is based on analyses using a wavelength of 352,5 nm. 5.2 Nickel hollow-cathode lamp 5.3 Vanadium hollow-cathode lamp 5.4 One-mark pipettes, conforming to ISO 648. 5.5 Flasks, of suitable capacity, conforming to ISO 4797. 6 Sampling Unless otherwise specified in the commodity specification, samples shall be taken as described in EN ISO 3170 or EN ISO 3171, and/or in accordance with the requirements of national standards or regulations for the sampling of the product under test.7 Procedure 7.1 Preparation of calibration solutions and the blank solution 7.1.1 Preparation of calibration solutions of nickel Prepare a set of calibration solutions with nickel contents of 0,5 mg/kg, 1 mg/kg, 2 mg/kg, 4 mg/kg and 7 mg/kg respectively. Either: a) heat standard fuels with known nickel contents (4.3) to 60 °C土5 °C and agitate vigorously i.e. by shaking by hand for at least 1 min. Dilute appropriately by mass with xylene (4.1). Prepare fresh solutions every day; or; b) dilute organometallic standards in oil (4.3) by mass with nickel free base oil (4.4) to obtain standards with nickel contents of 5 mg/kg, 10 mg/kg, 20 mg/kg, 40 mg/kg and 70 mg/kg. Further dilute 1+9 by mass with xylene (4.1). Prepare freshly every day. A stabilizer, supplied by the manufacturer of the organometallic standards in oil, may be used. In this case, the base oil diluted intermediate solutions are stable up to three months and need not be made freshly every day. If the sample contains more than 1 % (m/m) water, use as solvent a mixture of xylene (4.1) and propan-2-ol (isopropyI alcohol) (4.2) in the ratio of about 9:1, by mass or by volume instead of xylene only.NOTE A simple and efficient test to the presence of water can be executed by heating a few droplets of the sample in a test tube. In the presence of water, a clearly audible crackling noise will appear. 7.1.2 Preparation of calibration solutions of vanadium Prepare a set of calibration solutions with vanadium contents of 1 mg/kg, 2 mg/kg, 4 mg/kg, 10 mg/kg and 20 mg/kg respectively. Either: a) heat standard fuels with known vanadium contents (4.3) to 60。C土5。C and agitate vigorously i.e. by shaking by hand for at least 1 min. Dilute appropriately by mass with xylene (4.1). Prepare freshly every day; or; b) dilute organometallic standards in oil (4.3) by mass with vanadium free base oil (4.4) to obtain standards with vanadium contents of 10 mg/kg, 20 mg/kg, 40 mg/kg, 100 mg/kg and 200 mg/kg. Further dilute 1+9 by mass with xylene (4.1). Prepare freshly every day. BS EN 13131 pdf download.
