The Fertilisers (Sampling and Analysis) Regulations 1991

Determination 6.2 6.2.1 Transfer a suitable aliquot of the solution prepared in 6.1 (containing not more than 15 μ cobalt) to a 100 ml beaker, add 15 ml sodium citrate solution (3.8), dilute to about 50 ml with water and adjust the pH to between 3 and 4 by adding 2 N hydrochloric acid solution (3.3). (A precipitate of ferric hydroxide may form but this can be dissolved by heating the solution.) Cool to room temperature, add 10 ml hydrogen peroxide solution (3.5) and, after 5 minutes, 1 ml 2-nitroso-l-naphthol solution (3.7). Heat the solution to about 90°C and then allow to stand for 30 minutes at room temperature. Transfer the solution to a 125 ml separating funnel, add I 0 ml toluene (3.2), shake vigorously for 2 minutes, allow the phases to separate and discard the lower aqueous phase. 6.2.2 To the toluene extract add 20 ml 2 N hydrochloric acid solution (3.3), shake for 1 minute and discard the lower aqueous phase. Add 20 ml 2 N sodium hydroxide solution (3.9), shake for 1 minute and again discard the aqueous phase. Repeat the washing with a further 20 ml of 2 N sodium hydroxide solution (3.9). Finally run off the toluene solution through a little anhydrous sodium sulphate (3.1) into a clean dry stoppered tube. Carry out a blank determination repeating the procedure, but omitting the sample. Measure the absorbance of the magenta coloured solutions at a wave length of 367 nm in the spectrophotometer (4.1) with toluene (3.2) as reference. Determine the quantity of cobalt in the solution by reference to the calibration curve (6.3).

Calibration curve 6.3 Measure amounts of cobalt working standard solution (3.1 1) corresponding to 3, 6, 9, 12 and 15μ cobalt into five separate 100 ml beakers and proceed as described in 6.2 commencing at “. . . add 15 ml sodium citrate solution (3.8). . .”. Plot a calibration graph of the absorbance of the solutions against the corresponding amounts of cobalt (μ).

EXPRESSION OF RESULTS

7

The cobalt content in mg/kg is given by formula:

$$A×50V×M$ where: A = weight of cobalt taken for colour development as read from the calibration graph after allowing for the blank reading (mgr;) V = volume in ml of sample taken for colour development M = weight of sample in grams.$

11 — DETERMINATION OF MOLYBDENUM

SCOPE AND FIELD OF APPLICATION

1

This method is applicable to all fertilisers.

PRINCIPLE

2

The sample is dissolved in hydrochloric acid (after ashing if necessary) and the molybdenum complexed with thiocyanate in the presence of stannous chloride. The red coloured complex is extracted into an organic solvent mixture and its absorbance measured at 470 nm.

REAGENTS

3

• (3.1) Hydrochloric acid, 50% (V/V): dilute 50 ml concentrated hydrochloric acid solution (d= 1. 18 g/ml) to 100 ml with water.

• (3.2) Hydrochloric acid, 2 N solution.

• (3.3) Hydrochloric acid, N solution.

• (3.4) Nitric acid solution, 30% (V/V): dilute 30 ml nitric acid (d= 1.42 g/ml) with water to 100 ml.

• (3.5.1) Molybdenum solution (working standard):

• dissolve 1.84 g ammonium molybdate [(NH₄)₆Mo₇O₂₄.4H₂O] in water and dilute with water to 1 litre.

• (3.5.2) Molybdenum solution (working standard):

• dilute 1.0 ml stock solution (3.5.1) to 1 litre with water.

• (1 ml = 1μ molybdenum).

• Prepare this solution immediately prior to use.

• (3.6) Ammonium ferrous sulphate solution, 4 g per 100 ml.

• (3.7) Potassium thiocyanate solution, 40 g per 100 ml.

• (3.8) Sodium sulphate, anhydrous.

• (3.9) Stannous chloride solution: suspend 40 g stannous chloride dihydrate in 20 ml 6.5 N hydrochloric acid, add water to dissolve and dilute to 100 ml. Filter if turbid.

• (3.10) Solvent mixture: mix equal volumes of carbon tetrachloride and 3-methylbutan-1-ol.

APPARATUS

4

• (4.1) Spectrophotometer with 10 mm cells.

PREPARATION OF THE SAMPLE

5

See Method 1.

PROCEDURE

6

Preparation of the solution for analysis 6.1 In the absence of organic matter 6.1.1 Weigh to the nearest 0.001 g, 5 g of the prepared sample, place in a 100 ml beaker, add 10 ml hydrochloric acid solution (3.1) and evaporate to dryness on a steam bath. Extract the soluble salts with three successive 10 ml portions of boiling 2 N hydrochloric acid solution (3.2), decanting the solution each time through the same filter paper[^f00011] into a 50 ml graduated flask. Wash the filter paper with a little water, cool the solution to room temperature and make up to the mark with water. In the presence of organic matter 6.1.2 Weigh to the nearest 0.001 g, 5 g of the prepared sample into a silica dish and place a silica cover on top. Transfer the dish to a cold muffle furnace and gradually raise the temperature to about 475°C (not to exceed 500°C). Maintain at this temperature for at least 16 hours and then open the furnace and allow the crucible to cool. Add 10 ml hydrochloric acid solution (3.1) and evaporate to dryness on a steam bath. Extract the soluble salts with two successive 10 ml portions of boiling 2 N hydrochloric acid solution (3.2), decanting the solution each time through the same filter paper[^f00011] into a 50 ml graduated flask. Add 5 ml hydrochloric acid solution (3.1) and 5 ml nitric acid solution (3.4) to the residue in the dish and evaporate the mixture to dryness on a hot plate at low heat. Add 10 ml boiling hydrochloric acid solution (3.1) to the residue and filter the solution through the same filter paper into the 50 ml graduated flask. Wash the filter paper with water, cool the solution to room temperature and make up to the mark with water.

Determination 6.2 6.2.1 Transfer a suitable aliquot of the solution, prepared as in 6.1, to a 125 ml separating funnel, add I ml ammonium ferrous sulphate solution (3.6) and sufficient N hydrochloric acid (3.3) to bring the volume to 50 ml (see Note), then add 1 ml potassium thiocyanate solution (3.7) and mix. Add 1 ml stannous chloride solution (3.9) and mix again. Add exactly 7 ml solvent mixture (3.10), shake vigorously for two minutes and allow to separate for fifteen minutes. Filter the lower layer through a 7 cm paper into a small stoppered tube. (If the lower layer is not clear of if filtration is difficult, filter through a suitable column packed with anhydrous sodium sulphate (3.8), solid stannous chloride and plugged with cotton wool.) 6.2.2 Carry out a blank determination repeating the procedure but omitting the sample. Measure the absorbance of the solutions at a wave length of 470 nm, in the spectrophotometer (4.1) with water as reference. Determine the quantity of molybdenum in the solution by reference to the calibration curve (6.3). Note: The acidity of final solution must not exceed 1.5 N with respect to hydrochloric acid; with more strongly acid conditions, fading of the colour will occur.

Calibration curve 6.3 Transfer by pipette, 0, 5, 10, 15, 20 and 25 ml standard molybdenum solution (3.5.2) into a series of 125 ml separating funnels. To each funnel add 1 ml ammonium ferrous sulphate solution (3.6) and 25 ml of 2 N hydrochloric acid (3.2); dilute to 50 ml with water where necessary and proceed as described at 6.2.1, commencing at “then add I ml potassium thiocyanate solution (3.7) and mix. . .”. Plot a calibration curve of the absorbance of the solutions against the corresponding amounts of molybdenum (μg).

EXPRESSION OF RESULTS

7

The molybdenum content in mg/kg is given by the formula:

$$A×50V×M$ where: A = weight of molybdenum in the aliquot taken for colour development as read from the calibration curve after allowing for the blank reading (μg) V = volume in ml of aliquot taken for colour development M = weight of sample in grams.$

12. — DETERMINATION OF COPPER

SCOPE AND FIELD OF APPLICATION

1

This method is applicable to all fertilisers.

PRINCIPLE

2

The sample is ashed and dissolved in dilute hydrochloric acid or, if it contains no organic substances, it is dissolved directly in dilute hydrochloric acid. The solution is diluted and the copper content is determined by atomic absorption spectrophotometry.

REAGENTS

3

• (3.1) Hydrochloric acid (d = 1. 18 g/ml).

• (3.2) Hydrochloric acid, 6 N solution.

• (3.3) Hydrochloric acid, 0.5 N solution.

• (3.4) Hydrogen peroxide, approximately 100 volume, 30% by weight.

• (3.5.1) Copper solution[^f00012] (stock):

• weigh to the nearest 0.001 g, 1 g pure copper, dissolve in 25 ml 6 N hydrochloric acid solution (3.2), add 5 ml hydrogen peroxide (3.4) and dilute to 1 litre with water. 1 ml of this solution = 1,000 μ of copper (Cu).

• (3.5.2) Copper solution (dilute):

• dilute 10 ml of stock solution (3.5.1) to 100 ml with water and then dilute the resulting solution, 10 ml to I 00 ml with water. 1 ml of the final dilution = 10μ of copper (Cu).

APPARATUS

4

• (4.1) Atomic absorption spectrophotometer with a copper lamp (324.8 nm).

PREPARATION OF SAMPLE

5

See Method 1.

PROCEDURE

6

Preparation of the solution for analysis 6.1 In the absence of organic matter 6.1.1 Weigh to the nearest 0.001 g, 5 g of the prepared sample, place it in a 400 ml beaker, add carefully 5 ml hydrochloric acid (3.1) (there may be a vigorous reaction due to carbon dioxide formation). Add more hydrochloric acid, if necessary. When effervescence has stopped, evaporate to dryness on a steam bath, stirring occasionally with a glass rod. Add 15 ml 6 N hydrochloric acid solution (3.2) and 120 ml water. Stir with the glass rod, which should be left in the beaker, and cover the beaker with a watch glass. Boil the solution gently until dissolution appears complete and then filter through a filter paper[^f00013] into a 250 ml graduated flask. Wash the beaker and filter with 5 ml hot 6 N hydrochloric acid solution (3.2) and twice with boiling water. Cool and make up to the mark with water (the hydrochloric acid concentration of this solution should be about 0.5 N). In the presence of organic matter 6.1.2 Weigh to the nearest 0.001 g, 5 g of the prepared sample into a silica or platinum crucible and place the crucible into a cold mute furnace. Close the furnace and gradually raise the temperature to 450-475°C over about 90 minutes. Maintain this temperature for at least 16 hours and then open the furnace and allow the crucible to cool. Moisten the ash with water and transfer it into a 250 ml beaker. Wash the crucible with about 5 ml hydrochloric acid (3. 1) and add the latter slowly and carefully to the beaker (there may be a vigorous reaction due to carbon dioxide formation). If necessary, add more hydrochloric acid (3.1) with stirring, until all effervescence has stopped. Evaporate the solution to dryness, occasionally stirring with a glass rod. Add 15 ml 6 N hydrochloric acid solution (3.2) and 120 ml water. Stir with the glass rod, which should be left in the beaker, and cover with a watch glass. Boil the solution gently until dissolution appears complete and filter through a filter paper[^f00013] into a 250 ml graduated flask. Wash the beaker and filter with 5 ml of hot 6 N hydrochloric acid solution (3.2) and twice with boiling water. Cool and make up to the mark with water. (The hydrochloric acid concentration of this solution should be about 0.5 N.)

Blank solution 6.2 Prepare a blank solution from which only the sample has been omitted and allow for this in the calculation of the final results.

Determination 6.3 Preparation of sample and blank test solutions 6.3.1 Dilute the sample solutions (6.1.1 or 6.1.2) and the blank test solution (6.2) with 0.5 N hydrochloric acid solution (3.3) to a concentration within the optimal measuring range of the spectrophotometer. Preparation of the calibration solution 6.3.2 By diluting the standard solution (3.5.2) with 0. 5 N hydrochloric acid solution (3.3) prepare at least 5 standard solutions corresponding to the optimal measuring range of the spectrophotometer.

Measurement 6.4 Set up the spectrophotometer (4.1) at a wavelength of 324.8 nm using an oxidising air-acetylene flame. Spray successively, in triplicate, the standard solution (6.3.2), the sample solution and the blank test solution (6.3.1), washing the instrument through with distilled water between each spraying. Plot the calibration curve using the mean absorbances as the ordinates and the corresponding concentrations of copper μ/ml as the abscissae. Determine the concentration of copper in the final sample and blank solution by reference to the calibration curve.

EXPRESSION OF RESULTS

7

Calculate the copper content of the sample taking into account the weight of the test sample and the dilutions carried out in the course of the analysis. Express the result either as a percentage or as mg/kg.

13. — DETERMINATION OF IRON

SCOPE AND FIELD OF APPLICATION

1

This method is applicable to all fertilisers.

PRINCIPLE

2

The sample is ashed and dissolved in dilute hydrochloric acid or, if it contains no organic substances, it is dissolved directly in dilute hydrochloric acid. The solution is diluted and the iron content of the extract is determined by atomic absorption spectrophotometry.

REAGENTS

3

• (3.1) Hydrochloric acid (d= 1.18 g/ml).

• (3.2) Hydrochloric acid, 6 N solution.

• (3.3) Hydrochloric acid, 0.5 N solution.

• (3.4) Hydrogen peroxide, approximately 100 volume, 30% by weight.

• (3.5.1) Iron solution[^f00014] (stock):

• weigh to the nearest 0.001 g, 1 g pure iron, dissolve in 200 ml 6 N hydrochloric acid solution (3.2), add 16 ml hydrogen peroxide solution (3.4) and dilute to 1 litre with water.

• 1 ml of this solution = 1,000 μ of iron (Fe).

• (3.5.2) Iron solution (dilute):

• dilute 10 ml of stock solution (3.5.1) to 100 ml with water.

• 1 ml of this solution = 100 μ of iron (Fe).

• (3.6) Lanthanum chloride solution:

• dissolve 12 g lanthanum oxide in 150 ml water, add 100 ml 6 N hydrochloric acid solution (3.2) and dilute to 1 litre with water.

APPARATUS

4

• (4.1) Atomic absorption spectrophotometer with an iron lamp (248.3 nm).

PREPARATION OF SAMPLE

5

See Method 1.

PROCEDURE

6

Preparation of the solution for analysis 6.1 In the absence of organic matter 6.1.1 Weigh to the nearest 0.001 g, 5 g of the prepared sample, place it in a 400 ml beaker, add carefully 5 ml hydrochloric acid (3. 1) (there may be a vigorous reaction due to carbon dioxide formation). Add more hydrochloric acid, if necessary. When effervescence has stopped, evaporate to dryness on a steam bath, stirring occasionaly with a glass rod. Add 15 ml 6 N hydrochloric acid solution (3.2) and 120 ml water. Stir with the glass rod, which should be left in the beaker, and cover the beaker with a watch glass. Boil the solution gently until dissolution appears complete and then filter through a filter paper[^f00015] into a 250 ml graduated flask. Wash the beaker and filter with 5 ml of hot 6 N hydrochloric acid solution (3.2) and twice with boiling water. Cool and make up to the mark with water. (The hydrochloric acid concentration of this solution should be about 0.5 N.) In the presence of organic matter 6.1.2 Weigh to the nearest 0.001 g, 5 g of the prepared sample into a silica or platinum crucible and place the crucible in a cold muffle furnace. Close the furnace and gradually raise the temperature to 450-475° over about 90 minutes. Maintain this temperature for at least 16 hours and then open the furnace and allow the crucible to cool. Moisten the ash with water and transfer it into a 250 ml beaker. Wash the crucible with about 5 ml hydrochloric acid (3.1) and add the latter slowly and carefully to the beaker (there may be a vigorous reaction due to carbon dioxide formation). If necessary, add more hydrochloric acid (3.1) with stirring, until all effervescence has stopped. Evaporate the solution to dryness, occasionally stirring with a glass rod. Add 15 ml 6 N hydrochloric acid solution (3.2) and 120 ml water. Stir with the glass rod, which should be left in the beaker, and cover with a watch glass. Boil the solution gently until dissolution appears complete and filter through a filter paper[^f00016] into a 250 ml graduated flask. Wash the beaker and filter with 5 ml of hot 6 N hydrochloric acid solution (3.2) and twice with boiling water. Cool and make up to the mark with water. (The hydrochloric acid concentration of this solution should be about 0.5 N.)

Blank solution 6.2 Prepare a blank solution from which only the sample has been omitted and allow for this in the calculation of the final results.

Determination 6.3 Preparation of sample and blank test solutions 6.3.1 Dilute the sample solutions (6.1.1 or 6.1.2) and the blank test solution (6.2) with 0.5 N hydrochloric acid solution (3.3) to a concentration within the optimal measuring range of the spectrophotometer. The final solution must contain 10% (V/V) of the lanthanum chloride solution (3.6). Preparation of the calibration solutions 6.3.2 By diluting the standard solution (3.5.2) with 0.5 N hydrochloric acid solution (3.3) prepare at least 5 standard solutions of increasing concentration corresponding to the optimal measuring range of the spectrophotometer. The final solutions must contain 10% (V/V) of the lanthanum chloride solution (3.6).

Measurement 6.4 Set up the spectrophotometer (4.1), at a wave length of 248.3 nm using an oxidising air-acetylene flame. Spray successively, in triplicate, the standard solutions (6.3.2), the sample solution, and the blank test solution (6.3.1), washing the instrument through with distilled water between each spraying. Plot the calibration curve using the mean absorbances as the ordinates and the corresponding concentrations of iron in υ/ml as the abscissae. Determine the concentration of iron in the final sample and blank solutions by reference to the calibration curve.

EXPRESSION OF RESULTS

7

Calculate the iron content of the sample taking into account the weight of the test sample and the dilutions carried out in the course of the analysis. Express the result either as a percentage or as mg/kg.

14. — DETERMINATION OF MANGANESE

SCOPE AND FIELD OF APPLICATION

1

This method is applicable to all fertilisers.

PRINCIPLE

2

The sample is ashed and dissolved in dilute hydrochloric acid or, if it contains no organic substances, it is dissolved directly in dilute hydrochloric acid. The solution is diluted and the manganese content of the extract is determined by atomic absorption spectrophotometry.

REAGENTS

3

• (3.1) Hydrochioricacid(d=1.18g/ml).

• (3.2) Hydrochloric acid, 6 N solution.

• (3.3) Hydrochloric acid, 0.5 N solution.

• (3.4.1) Manganese solution[^f00017] (stock):

• weigh to the nearest 0.001 g, 1g pure manganese, dissolve in 25 ml 6 N hydrochloric acid solution (3.2) and dilute to 1 litre with water. 1 ml of this solution= 1,000 μ of manganese (Mn).

• (3.4.2) Manganese solution (dilute):

• dilute 10 ml of stock solution (3.4.1) to 1 litre with water. 1 ml of this solution=10 μ of manganese.

• (3.5) Lanthanum chloride solution:

• dissolve 12 g lanthanum oxide in 150 ml water, add 100 ml 6 N hydrochloric acid solution (3.2) and dilute to 1 litre with water.

APPARATUS

4

• (4.1) Atomic absorption spectrophotometer with a manganese lamp (279.5 nm).

PREPARATION OF SAMPLE

5

See Method 1.

PROCEDURE

6

Preparation of the solution for analysis 6.1 In the absence of organic matter 6.1.1 Weigh to the nearest 0.001 g, 5 g of the prepared sample, place it in a 400 ml beaker, add carefully 5 ml hydrochloric acid (3.1) (there may be a vigorous reaction due to carbon dioxide formation). Add more hydrochloric acid, if necessary. When effervescence has stopped, evaporate to dryness on a steam bath, stirring occasionally with a glass rod. Add 15 ml 6 N hydrochloric acid solution (3.2) and 120 ml water. Stir with the glass rod, which should be left in the beaker, and cover the beaker with a watch glass. Boil the solution gently until dissolution appears complete and then filter through a filter paper[^f00018] into a 250 ml graduated flask. Wash the beaker and filter with 5 ml of hot 6 N hydrochloric acid solution (3.2) and twice with boiling water. Cool and make up to the mark with water. (The hydrochloric acid concentration of this solution should be about 0.5 N.) In the presence of organic matter 6.1.2 Weigh to the nearest 0.001 g, 5 g of the prepared sample into a silica or platinum crucible and place the crucible into a cold muffle furnace. Close the furnace and gradually raise the temperature to 450-475°C over about 90 minutes. Maintain this temperature for at least 16 hours and then open the furnace and allow the crucible to cool. Moisten the ash with water and transfer it into a 250 ml beaker. Wash the crucible with about 5 ml hydrochloric acid (3. 1) and add the latter slowly and carefully to the beaker (there may be a vigorous reaction due to carbon dioxide formation). If necessary, add more hydrochloric acid (3. 1) with stirring, until all effervescence has stopped. Evaporate the solution to dryness, occasionally stirring with a glass rod. Add 15 ml of 6 N hydrochloric acid solution (3.2) and 120 ml water. Stir with the glass rod, which should be left in the beaker, and cover with a watch glass. Boil the solution gently until dissolution appears complete and filter through a filter paper[^f00018] into a 250 ml graduated flask. Wash the beaker and filter with 5 ml of hot 6 N hydrochloric acid solution (3.2) and twice with boiling water. Cool and make up to the mark with water. (The hydrochloric acid concentration of this solution should be about 0.5 N.)

Blank solution 6.2 Prepare a blank solution from which only the sample has been omitted and allow for this in the calculation of the final results.

Determination 6.3 Preparation of sample and blank test solutions 6.3.1 Dilute the sample solutions (6.1.1 or 6.1.2) and the blank test solution (6.2), with 0.5 N hydrochloric acid solution (3.3) to a concentration within the optimal measuring range of the spectrophotometer. The final solution must contain 10% (V/V) of the lanthanum chloride solution (3.5). Preparation of the calibration solutions 6.3.2 By diluting the standard solution (3.4.2) with 0. 5 N hydrochloric acid solution (3.3) prepare at least 5 standard solutions of increasing concentration corresponding to the optimal measuring range of the spectrophotometer. The final solutions must contain 10% (V/V) of the lanthanum chloride solution (3.5).

Measurement 6.4 Set up the spectrophotometer (4.1), at a wave length of 279.5 nm using an oxidising air-acetylene flame. Spray successively, in triplicate, the standard solutions (6.3.2), the sample solution and the blank test solution (6.3.1), washing the instrument through with distilled water between each spraying. Plot the calibration curve using the mean absorbances as the ordinates and the corresponding concentrations of manganese υ/ml as the abscissae. Determine the concentration of manganese in the final sample and blank solutions by reference to the calibration curve.

EXPRESSION OF RESULTS

7

Calculate the manganese content of the sample taking into account the weight of the test sample and the dilutions carried out in the course of the analysis. Express the result either as a percentage or as mg/kg.

15. — DETERMINATION OF THE NEUTRALISING VALUE IN LIMING MATERIALS

SCOPE AND FIELD OF APPLICATION

1

This method is applicable to products in Groups 5(a) and 5(b) of Section A of the Table in Schedule I of the Fertilisers Regulations 1990[^f01031].

PRINCIPLE

2

The sample is dissolved in a measured quantity of standard hydrochloric acid, the excess of which is titrated with a standard solution of sodium hydroxide.

REAGENTS

3

• (3.1) Hydrochloric acid, 0.5 N solution.

• (3.2) Sodium hydroxide, 0.5 N solution (carbonate free).

• (3.3) Phenolphthalein indicator solution: dissolve 0.25 g phenolphthalein in 150 ml 95% ethanol and dilute with water to 250 ml.

PREPARATION OF SAMPLE

4

Rapidly grind 50 g of the representative lime sample to pass through a 1 mm sieve.

PROCEDURE

5

Determination 5.1 Weigh to the nearest 0.001 g, 0. 5 g of the prepared sample and transfer to a 300 ml conical flask. Add 50 ml of 0.5 N hydrochloric acid (3.1), cover the flask with a watch glass and boil the contents gently for five minutes. Cool the mixture to room temperature, add two or three drops of the phenolphthalein indicator (3.3) and titrate with 0.5 N sodium hydroxide solution (3.2) to the end point of the indicator.

EXPRESSION OF RESULTS

6

Determine the amount of hydrochloric acid consumed by the sample. 1 ml 0.5 N hydrochloric acid=0.01402 g calcium oxide (CaO).

16. — DETERMINATION OF FINENESS OF PRODUCTS OTHER THAN POTASSIC BASIC SLAG

SCOPE AND FIELD OF APPLICATION

1

This method is applicable to “Rock phosphate” in Group 2(b) and to products in Groups 4(c), 5(a) and 5(b) of Section A of the Table in Schedule I of the Fertilisers Regulations 1990[^f01032].

PRINCIPLE

2

By hand sieve shaking, the proportion of material passing through the prescribed sieve is determined.

APPARATUS

3

Sieves having square apertures of 45 mm, 6.7 mm, 6.3 mm, 5 mm, 3.35 mm, 1.0 mm and 150 microns; lower receiver to fit sieve. Test sieves conforming to British Standard 410: 1986 are suitable.

PROCEDURE

4

For sieving through 3.5 mm, 1.0 mm and 150 micron sieves 4.1 Thoroughly mix the sample and quarter down until a portion of about 100 g is obtained. Heat this portion at 1OO°C until dry and thoroughly mix. Weigh to the nearest 0.01 g, 20 g and transfer to the sieve with the lower receiver attached. Proceed as described in 4.4.

For sieving through 6.7 mm, 6.3 mm and 5 mm sieves 4.2 Oven dry the sample at 1OO°C for 24 hours and thoroughly mix. Weigh to the nearest 0.1 g, 200 g and transfer to the sieve with the lower receiver attached. Proceed as described in 4.4.

For sieving through a 45 mm sieve 4.3 If the sample appears moist or damp, oven dry at 1OO°C for 24 hours, but if the sample appears dry, heating is not necessary. Thoroughly mix the sample and weigh to the nearest 0.1 g, 500 g and transfer to the sieve with the lower receiver attached. Proceed as in 4.4.

Sieving 4.4 Shake the sieve for 5 minutes, frequently tapping the side. Disintegrate soft lumps such as can be caused to crumble by the application of the fibres of a soft brush, taking care that the hard part of the brush does not make contact with the sieve and that the brush is not used to brush particles through the sieve. Brush out the powder in the lower receiver and weigh. Replace the receiver and repeat the shaking and tapping procedure for 2 minutes. Add the powder in the receiver to the first portion and weigh. Repeat the process until not more than 0.04 g passes through the seive during 2 minutes.

EXPRESSION OF RESULTS

5

Calculate the fineness by expressing the weight of the material passing through the sieve as a percentage of the weight of the portion of the dried (or as the case may be, undried) sample taken for sieving.

17. — DETERMINATION OF FINENESS OF POTASSIC BASIC SLAG

SCOPE AND FIELD OF APPLICATION

1

Exclusively to “Potassic basic slag” in Group 3(b) of Section A of the Table in Schedule 1 of the Fertilisers Regulations 1990[^f01033].

PRINCIPLE

2

By hand sieve shaking and dissolution of the soluble salts, the proportion of slag passing through the prescribed sieve is determined.

APPARATUS

3

Sieve having square apertures of 0.5 mm (500 microns); lower receiver to fit sieve. Test sieves conforming to British Standard 410: 1986 are suitable.

PROCEDURE

4

Preparation of the sample 4.1 Thoroughly mix the sample and quarter down until a portion of about 100 g is obtained. Heat this portion at 1OO°C until dry and thoroughly mix.

Sieving 4.2 Weigh to the nearest 0.1 g, 20 g of the dry sample and transfer to the sieve with the lower receiver attached. Shake the sieve for five minutes, frequently tapping the sides. Disintegrate soft lumps that can be caused to crumble by the application of a soft brush, taking care that the hard part of the brush does not make contact with the sieve and that the brush is not used to brush particles through the sieve. Transfer the finer portion from the container into a 500 ml beaker and add 200 mi of previously boiled water. Stir and then filter through a weighed glass sintered crucible. Thoroughly wash the residue with water, dry and re-weigh the crucible. Calculate the weight of slag in the mixture with a particle size of less than 0.5 mm (A). Weigh to the nearest 0.01 g, about 20 g of the dry sample and transfer to a 500 ml conical flask. Add 200 ml previously boiled water and shake for 30 minutes. Filter through a weighed, sintered glass crucible, wash the residue thoroughly with water, dry and re-weigh the crucible. Calculate the total weight of slag in the mixture (B).

EXPRESSION OF RESULTS

5

$Express the fineness of the slag asAB×100.$

SCHEDULE 3 — FORM OF CERTIFICATE OF ANALYSIS

Signed

In witness whereof the Official Seal of the Minister of Agriculture, Fisheries and Food is hereunto affixed on

John Selwyn Gummer — Minister of Agriculture, Fisheries and Food — 26th March 1991.

Strathclyde — Parliamentary Under Secretary of State, Scottish Office — 27th March 1991

David Hunt — Secretary of State for Wales — 25th March 1991

Explanatory note

(This note is not part of the Regulations)

These Regulations, which apply throughout Great Britain, consolidate and supersede the Fertilisers (Sampling and Analysis) Regulations 1978 (SI. 1978/1108) and the Fertilisers (Sampling and Analysis) (Amendment) Regulations 1980 (SI. 1980/1130). They implement the Directives listed in paragraph 2 below.

2 The Directives implemented are: Commission Directive 77/535/EEC (OJ No. L213, 22.8.77) on the approximation of the laws of the Member States relating to methods of sampling and analysis for fertilisers; Commission Directive 79/138/EEC (OJ No. L39, 14.2.79, p. 3) amending Directive 77/535/EEC in respect of methods of analysis for magnesium; Commission Directive 87/94/EEC (OJ No. L38, 7.2.87) on the approximation of the laws of Member States relating to procedures for the control of characteristics of, limits for and, resistance to detonation of straight ammonium nitrate fertilisers of high nitrogen content; Commission Directive 87/566/EEC (OJ No. L342, 4.12.87, p. 32) amending Directive 77/535/EEC in respect of methods of sampling for fluid fertilisers; Commission Directive 88/126/EEC (OJ No. L63, 9.3.88, p. 12) amending Directive 87/94/EEC, in respect only of its date for implementation by the Member States.

3 The Regulations provide for a number of matters concerning the sampling and analysis of fertilisers including: a the amounts of fertilisers from which samples are to be taken (regulation 2); b the manner of taking, marking, sealing and fastening up of samples (regulation 3 and Schedule 1); c the methods of sending part of a sample (regulation 4); d the required qualifications of agricultural analysts and deputy agricultural analysts (regulation 5); e the methods by which analyses are to be carried out (regulation 6 and Schedule 2) and the form of certificate of analysis (regulation 7 and Schedule 3).

4 The principal changes from the superseded Regulations are the introduction of sampling procedures for fluid fertilisers (in Schedule 1) and of methods of analysis for straight ammonium nitrate fertiliser (in Schedule 2).

5 The Regulations come into force on 20th May 1991.

Footnotes

[^f00001]: 1970 c. 40; section 74A was inserted by paragraph 6 of Schedule 4 to the European Communities Act 1972 (c. 68) and the Act was amended by the Agriculture Act 1970 Amendment Regulations 1982 (S.I. 1982/980). Section 66(1) contains definitions of the expressions “prescribed” and “regulations”.

[^f00002]: In the case of the Secretary of State for Wales, by virtue of S.I. 1978/272.

[^f00003]: 1926 c. 45.

[^f00004]: S.I. 1990/887.

[^f00005]: S.I. 1978/1108.

[^f00006]: S.I. 1980/1130.

[^f00007]: Whatman 42 or equivalent.

[^f00008]: Whatman 42 or equivalent.

[^f00009]: Whatman 541 or equivalent.

[^f00010]: Whatman 541 or equivalent.

[^f00011]: Whatman 541 or equivalent.

[^f00012]: Commercially available standard copper solution may be used.

[^f00013]: Whatman 541 or equivalent.

[^f00014]: Commercially available standard iron solution may be used.

[^f00015]: Whatman 541 or equivalent.

[^f00016]: Whatman 541 or equivalent.

[^f00017]: Commercially available standard manganese solution may be used.

[^f00018]: Whatman 541 or equivalent.

[^f01003]: Biuret can be prified beforehand by washing with ammoniacal solution (10%), then with acetone and drying in a vacuum.

[^f01004]: S.I. 1990/887.

[^f01005]: S.I. 1990/887.

[^f01006]: S.I. 1990/887.

[^f01007]: S.I. 1990/887.

[^f01008]: S.I. 1990/887.

[^f01009]: Where the fertiliser is normal superphosphate or concentrated superphosphate in Group 2(a) of Section A, or NPK fertiliser in Group 1, NP fertiliser in Group 2, or PK fertiliser in Group 4 of Section B or NPK fertiliser suspension, NP fertiliser suspension or PK fertiliser suspension in Section C of the Table in Schedule 1 of the Fertilisers Regulations 1990.

[^f01010]: Where the fertiliser is triple superphosphate in Group 2(a) of Section A, or NPK fertiliser containing soft ground rock phosphate or partially solubilised rock phosphate in Group 1, or NP fertiliser containing soft ground rock phosphate or partially solubilised rock phosphate in Group 2, or PK fertiliser containing soft ground rock phosphate or partially rock phosphate in Group 4 of Section B of the Table in Schedule 1 of the Fertilisers Regulations 1990.

[^f01011]: If no mechnical shaker is available, the flask may be shaken by hand every 5 minutes.

[^f01012]: Phosphorus soluble in mineral acids, water soluble phosphorus, phosphorus soluble in solutions of ammonium citrate, phosphorus soluble in 2% citric acid and phosphorus soluble in 2% formic acid.

[^f01013]: 21 ml when the solution to be precipitated contains more than 15 ml of citrate solution (neutral citrate, Petermann or Joulie alkaline citrate).

[^f01014]: To precipitate phosphate solutions containing more than 15 ml citrate solution (neutral, Petermann or Joulie) which have been acified with 21 ml concentrated nitirc acid (see footnote to paragraph 6.1) use 80 ml of the precipitating reagent.

[^f01015]: S.I. 1990/887.

[^f01016]: S.I. 1990/887.

[^f01017]: S.I. 1990/887.

[^f01018]: S.I. 1990/887.

[^f01019]: S.I. 1990/887.

[^f01020]: S.I. 1990/887.

[^f01021]: A reaction time of one-and-a-half hours is sufficient in the case of most of the organic substances in the presence of silver nitrate catalyst.

[^f01022]: Commercially available standard copper solution may be used.

[^f01023]: Whatman 541 or equivalent.

[^f01024]: S.I. 1990/887.

[^f01025]: S.I. 1990/887.

[^f01026]: S.I. 1990/887.

[^f01027]: S.I. 1990/887.

[^f01028]: S.I. 1990/887.

[^f01029]: S.I. 1990/887.

[^f01030]: S.I. 1990/887.

[^f01031]: S.I. 1990/887.

[^f01032]: S.I. 1990/887.

[^f01033]: S.I. 1990/887.