Diflufenican aqueous suspension concentrates
COMMON NAME: diflufenican (ISO)
EMPIRICAL FORMULA: C19H11F5N2O2
CAS REGISTRY NUMBER: 83164-33-4
CIPAC CODE NUMBER: 462
FAO Specification 462/TC/S/F (1997)
The material shall consist of diflufenican together with related manufacturing impurities and shall be a brown damp crystalline powder free from visible extraneous matter and added modifying agents.
2. ACTIVE INGREDIENT
2.1 Identity tests (462/TC/M/2, CIPAC H, to be published) (Note 1)
An identity test is required if the identity of the active ingredient is in doubt (e.g. chromatographic retention time under analytical conditions of the method of analysis or IR Spectrum).
2.2 Diflufenican (462/TC/M/3, CIPAC H, to be published) (Note 1)
The diflufenican content shall be declared (not less than 970 g/kg expressed on the dry weight basis) and, when determined, the content obtained shall not differ from that declared by more than ± 25 g/kg.
3.1 Water (MT 30.2, CIPAC F, p. 93)
Maximum: 100 g/kg.
4. PHYSICAL PROPERTIES
4.1 Melting point (MT 2 on the dried material, CIPAC F, p. 5)
The melting point shall be in the range 159-160°C and shall not be depressed on admixture with an equal quantity of pure diflufenican.
4.2 pH range (MT 75, CIPAC F, p. 205)
pH range: 5.0 to 7.0.
NOTE 1. Methods available from the Pesticides Information Officer, FAO Plant Production and Protection Division.
FAO Specification 462/SC/S/F (1997)
The material shall consist of a suspension of fine particles of technical diflufenican, complying with the requirements of FAO specification 462/TC/S/F (1997), in an aqueous phase, together with suitable formulants. After gentle agitation, the material shall be homogeneous (Note 1) and suitable for further dilution in water.
2. ACTIVE INGREDIENT
2.1 Identity tests (462/SC/M/2, CIPAC H, to be published) (Note 2)
An identity test is required if the identity of the active ingredient is in doubt (e.g. chromatographic retention time under conditions of the method of analysis or IR Spectrum).
2.2 Diflufenican (462/SC/M/3, CIPAC H, to be published) (Note 2)
The diflufenican content shall be declared (g/l at 20°C, Note 3) and, when determined, the content obtained shall not differ from that declared by more than the following amounts:
up to 100 g/l
± 10% of the declared content
above 100 up to 250 g/l
± 6% of the declared content
above 250 up to 500 g/l
± 5% of the declared content
above 500 g/l
± 25 g/l
3. PHYSICAL PROPERTIES
3.1 Mass per millilitre at 20°C (MT 3.3, CIPAC F, p. 18) (Note 3)
The range of the mass per millilitre (g/ml) at 20°C shall be declared.
3.2 pH range (MT 75, CIPAC F, p. 205)
pH range: 5.0 to 9.0.
3.3 Pourability (MT 148, CIPAC F, p. 348) (Note 4)
Maximum "residue": 5%.
Maximum "rinsed residue": 0.25%.
3.4 Spontaneity of dispersion (MT 160, CIPAC F, p. 391) (Note 5)
A minimum of 80 % of the content found under 2.2 shall be in suspension after 5 min. in CIPAC Standard Water D at 30°C ± 2°C.
Alternatively, if the buyer required other CIPAC Standard Waters or temperatures to be used, then this shall be specified when ordering.
3.5 Suspensibility (MT 161, CIPAC F, p. 394. Note 5)
A minimum of 70% of the content found under 2.2 shall be in suspension after 30 min. in CIPAC Standard Water D at 30°C ± 2°C.
Alternatively, if the buyer requires other CIPAC Standard Waters or temperatures to be used, then this shall be specified when ordering.
3.6 Wet sieve test (MT 59.3, CIPAC F, p. 179. Note 6)
Maximum: 1% of the product shall be retained on a 75 ìm test sieve.
3.7 Persistent foam (MT 47.2, CIPAC F, p. 152)
Maximum: 15 ml after 1 min. (10 g/l dilution).
4. STORAGE STABILITY
4.1 Stability at 0°C (MT 39.1, CIPAC F, p. 128)
After storage at 0°C ±1°C for 7 days, the product shall continue to comply with 3.4, 3.5 and 3.6.
4.2 Stability at 54°C (MT 46.1, CIPAC F, p. 149)
After storage at 54 ± 2°C for 14 days, the determined average active ingredient content must not be lower than 95% relative to the determined average content found before storage (Note 7) and the product shall continue to comply with 3.2, 3.3, 3.4, 3.5 and 3.6.
1. Before sampling to verify product quality, inspect the commercial container carefully. On standing, suspension concentrates usually develop a concentration gradient from the top to the bottom of the container. This may even result in the appearance of a clear liquid on the top and/or of sediment on the bottom. Therefore, before sampling, homogenize the product according to the instructions given by the manufacturer or, in the absence of such instructions, by gentle shaking of the commercial container (for example by inverting the closed container several times). Large containers must be opened and stirred adequately. After this procedure, the container should not contain a sticky layer of non-dispersed product at the bottom. A suitable and simple method of checking for a non-dispersed sticky layer ("cake") is by probing with a glass rod or similar device adapted to the size and shape of the container. All the physical and chemical tests must be carried out on a laboratory sample taken after the recommended homogenization procedure.
2. Methods available from the Pesticides Information Officer, FAO Plant Production and Protection Division
3. Unless homogenization is carried out carefully, it is possible for the sample to become aerated. This can lead to errors in the determination of the density and in calculation of the active ingredient content (in g/l) if methods other than MT 3.3 are used. If the buyer requires both g/kg and g/l at 20°C, then in case of dispute, the analytical result shall be calculated in g/kg.
4. This is to ensure that the user can make use of the maximum amount of the product in the container. Suspension concentrates are fairly viscous products. The test determines the ease with which the formulation pours out of the container and how easily it rinses out.
5. Chemical assay is the only fully reliable method of measuring the mass of active ingredient still in suspension. However, simpler methods such as gravimetric and solvent extraction determination may be used on a routine basis provided that these methods have been shown to give equal results to those of the chemical assay method. In case of dispute the chemical method shall he the "Referee method".
6. This test detects coarse particles (e.g. caused by crystal growth) or agglomerates (crust formation) or extraneous materials which could cause blockage of spray nozzles or filters in the spray tank.
7. Analysis of the product before and after storage should he carried out at the same time (i.e. after storage) to reduce the analytical error.