BS ISO 13546:2021 pdf download – Copper concentrates — Determination of mercury content — Cold vapour atomic absorption spectrometric method 5.13 Hydroxylamine hydrochloride solution, 20 g/l. Add 2 g of hydroxylamine hydrochloride (5.3) to 100 ml of deionized water. 5.14 Mercury trapping solution. Add 10 g of potassium permanganate (5.2) to 100 ml of water and mix well. This reagent is used to oxidize mercury vapour to its Hg 2+ state and trap it in solution. 5.15 Nitric acid solution, diluted (1+9). 5.16 Mercury standard solution A, 100 µg/ml. Weigh 0,1354 g of mercury (II) chloride (5.4) into a 250 ml beaker and dissolve in 100 ml of nitric acid (5.5). Quantitatively transfer to a 1-l volumetric flask with water. Mix and store in a labelled glass container. Alternatively, use a suitable high-quality commercial standard solution. 5.17 Mercury standard solution B, 10 µg/ml. Pipette 10 ml of mercury standard solution A (5.16) into a 100-ml volumetric flask containing 10 ml nitric acid (5.5). Dilute to volume with water. Mix and store in a labelled volumetric flask. Prepare the solution monthly. 5.18 Mercury standard solution C, 0,1 µg/ml. Pipette 10 ml of mercury standard solution B (5.17) into a 1-l volumetric flask containing 100 ml of nitric acid (5.5). Dilute to volume with water. Mix and store in a labelled volumetric flask. The solution should be freshly prepared. 6 Apparatus All laboratory glassware and equipment shall be free of mercury contamination. Use ordinary laboratory apparatus, including pipettes and volumetric flasks conforming with the specifications of ISO 648 and ISO 1042, respectively, and the following: 6.1 Analytical balance, sensitive to 0,1 mg. 6.2 Magnetic stirrers. 6.3 Laboratory glassware, of class A conforming with ISO 385, ISO 648, ISO 1042 and used in accordance with ISO 4787. 6.4 Atomic absorption spectrometer, equipped with a mercury hollow cathode lamp or electrodeless discharge lamp or a continuum radiation source. WARNING — Follow the manufacturer’s instructions to avoid possible explosion hazards when igniting and extinguishing the air-acetylene flame and possible burning from the hot electric furnace. Wear tinted safety glasses whenever the atomic absorption spectrometer is in operation. Good ventilation is necessary to prevent poisoning by mercury hydride. The atomic absorption spectrometer used in this method shall meet the following criteria: a) Minimum sensitivity: the absorbance of the highest concentration calibration solution (see 8.7) is at least 0,5 µg/ml. b) Graph linearity: the slope of the...
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