ISO 6851:2001 pdf download
ISO 6851:2001 pdf download.Photography -Processing waste 一Determination of total amino nitrogen(microdiffusion Kjeldahl method).
5.3 Safety precautions
ALL PIPETTE OPERATIONS SHALL BE PERFORMED WITH A PIPETTE BULB OR PLUNGER PIPETTE. THIS
IS A CRITICAL SAFETY WARNING!
Safety glasses shall be worn for all laboratory work.
6 Materials and reagents
6.1 General
6.1.1 Handling and labelling
Reagents shall be handled in conformity with health and safety precautions as shown on containers, or as given in other sources of such information. Proper labelling of prepared reagents includes the chemical name, date of preparation, expiration date, restandardization date, name of preparer, and adequate health and safety precautions. The discharge of reagents shall conform to applicable environmental regulations.
6.1.2 Purity
Reagents used in the test procedures shall be certified reagent-grade chemicals and shall meet appropriate standards, or be chemicals of a purity acceptable for the analysis. For details, see ISO 6353-1, ISO 6353-2 and ISO 6353-3.
6.1.3 Water
Whenever water is specified without other qualifiers in the test procedures, only distilled water or water of
equivalent purity shall be used.
6.1.4 Strength of solutions
6.1.4.1 Acids and ammonium hydroxide are full strength unless otherwise specified.
6.1.4.2 When a standardized solution is required, its amount-of-substance concentration is expressed in moles per litre. The number of significant figures to which the molarity is known shall be sufficient to ensure that the reagent does not limit the reliability of the test method.
6.1.4.3 When a standardized solution is not required, its concentration is expressed in grams per litre (gil) to the appropriate number of significant figures.
6.1.4.4 When a solution is to be diluted, its dilution is indicated by (X + )‘), meaning that X volumes of reagent, or concentrated solution, are to be diluted with Yvolumes of water (6.1.3).
Weigh 2 g ± 0,1 g of red mercury(ll) oxide, Hg01) (DANGER: ((B))((C))((S))), and dissolve it in 25 ml of 3 mol/l sulfuric acid solution (6.2.4) (DANGER: (C)) in a small beaker. Add the contents of the beaker to the acidified potassium sulfate solution, and rinse the beaker into the flask. Dilute the solution to volume when cool, and mix well. Store this solution at a temperature above 14 °C to prevent crystallization.
6.2.2 Potassium tetraborate solution, 514 g/l.
Weigh 673 g ± 0,1 g of potassium tetraborate, K2B407 4HO, and dissolve it in 550 ml of water in a 1 litre beaker. Then weigh 247 g ± 0,1 g of potassium hydroxide, KOH (DANGER: ((C))), and dissolve it in the tetraborate solution. Boil on a hotplate for 5 mm, cool and add 5 ml of a 10% aqueous solution of nonylphenoxypoly (6-10) ethylene oxide, NPPO, or similar wetting agent2). Transfer the mixture to a 1 litre volumetric flask, rinsing the beaker into the flask several times. When cool, dilute to volume and mix well. Note that the wetting agent will separate out on standing; therefore, the flask must be shaken vigorously before each use.
6.2.3 Boric acid absorbent solution
Add about 800 ml of water to a 1 litre volumetric flask. Stir, using a magnetic stirrer, and add 2 mg to 3 mg of xylene cyanole FF, weighed to the nearest 1 mg, followed by 0,5 ml of NPPO, followed by 5,0 ml of methyl red indicator solution prepared by dissolving 0,125 g of methyl red in 250 ml of methanol (DANGER: (F)(S)). Add 6 g ± 0,1 g of boric acid, H3B03, keeping the contents of the flask stirred until all the constituents are dissolved. Dilute to within about 15 ml of the mark and mix. Place 1,5 ml of this solution in the centre of a microdiffusion cell and observe the colour.
If the colour in the cell is pink, add just sufficient 0,1 mol/l sodium hydroxide (6.2.9) to the solution in the 1 litre flask to obtain a neutral colour when 1 ml is viewed in the microdiffusion cell.
Check that excess sodium hydroxide is absent by adding 0,10 ml of 0,00250 mol/l sulfuric acid (6.2.7) to 1 ml of the solution, at which point a pink colour should be produced. Note that the solution in the 1 litre flask will appear red, even when the 1 ml in the microdiffusion cell looks neutral.
6.2.4 Sulfuric acid solution, c(H2S04) 3 mol/l (DANGER: (C)).
Carefully add 170 ml of sulfuric acid (((C))), p 1,84 g/ml, to 500 ml of water in a 1 litre volumetric flask while mixing and cooling. Dilute to the mark with water.
6.2.5 Sulfuric acid solution, c(H2S04) 0,5 mol/l.
Carefully add 28,3 ml of sulfuric acid (((C))), p 1,84 g/ml, to 500 ml of water in a 1 litre volumetric flask while mixing and cooling. Dilute to the mark with water.