BS ISO 19051 pdf free download

BS ISO 19051-2015 pdf free download.Rubber, raw natural, and rubber latex, natural 一 Determination of nitrogen content by Micro Dumas combustion method.
6 Calibration
The instrument shall be calibrated in accordance with the schedule given in Annex A.
7 Sampling and preparation of test piece
7.1 For the determination of nitrogen in raw solid rubber, take the laboratory sample in accordance with the method specified in Iso 1795 and prepare the test piece from the laboratory sample. The test piece is to be cut into small thin pieces using suitable tools such as scissors or knife.
7.2 For the determination of nitrogen in raw latex, take the laboratory sample in accordance with
ISO 123.
To prepare the dried latex test piece, take an accurately weighed clean and dry aluminium foil dish. Measure 10 ml from the laboratory sample and put it in the aluminium foil dish. Put the aluminium foil dish in a 110 °C vacuum oven and heat for 15 mm until completely dry. Remove the aluminium foil dish from the oven and cool in a desiccator. If the dried sample becomes excessively sticky, sample can be dried at 70 °C ± 2 °C.
A dried latex test piece can also be prepared in accordance with ISO 124:2013, 6.2.
7.3 Weigh the test piece within the range of 0,50 mg to 1,50 mg using the analytical microbalance nearest to 1,00 rng ± 0,01 mg.
7.4 Allow all the weighed test pieces and the analytical microbalance to equilibrate to room temperature for at least 30 mm.
7.5 Use a pair of tweezers to place an empty tin capsule on balance and tare the weight.
7.6 Remove the tin capsule using a pair of tweezers and place on metal sample prep block.
7.7 Fill capsule with the desired test piece (generally 050 mg to 150 mg) and ensure that the test piece is fully encapsulated.
7.8 Tap the encapsulated test piece on a clean surface to remove any remnants on the outside of the encapsulated test piece.
7.9 Place the encapsulated test piece on the balance and record the weight.
7.10 Put the encapsulated test piece in numbered sample tray.
8 Procedure
8.1 General
Turn on the power to the instrument as per instruction of the instrument manufacturer.
8.2 Equipment check
8.2.1 Blank run
a) It is used to establish the instrumental readings for carbon, hydrogen, nitrogen, and sulfur, so as to apply the required correction during the actual test run. It also indicates the stability of the system.
b) Run the empty tin capsules as per manufacturer’s instruction.
8.2.2 K-Factor run
a) It is the sensitivity factor which is required to convert the electrical signal from the detector to weight percent results.
b) Run analytical standards of known composition, mentioned under the reagent list as per manufacturer’s instruction.BS ISO 19051 pdf download.