This standard applies to the determination of the stability of pesticide emulsions.
1. Reagents and solutions 1. Anhydrous calcium chloride (HGB 3208-60): analytically pure;
2. Magnesium chloride six crystal water (GB 672-65): analytically pure;
3. Calcium carbonate (HGB 3117-59): analytically pure;
4. Magnesium oxide (HGB 3114-59): analytically pure;
5. Hydrochloric acid (GB 622-77): analytically pure;
6. Standard hard water: It has a hardness of 342 ppm based on calcium carbonate. The preparation method is as follows:
(1) 0.304 g of anhydrous calcium chloride and 0.139 g of magnesium chloride with crystal water were weighed and diluted to 1 liter with distilled water.
(2) Dissolve 2.740 g of calcium carbonate and 0.276 g of magnesium oxide in a small amount of 2N hydrochloric acid, and evaporate to dryness on a water bath to remove excess hydrochloric acid. The residue was then dissolved in a 100 ml volumetric flask and diluted to the mark with distilled water, and 10 ml of water was added and diluted to 1000 ml.
Either of the above two methods may be selected.
Second, the instrument 7. Measuring cylinder: 100 ml, inner diameter 28 ± 2 mm, height 250 ± 5 mm;
8. Beaker: 250 ml, diameter 60-65 mm;
9. Glass stir bar: 6-8 mm in diameter;
10. Pipette: 5 ml (with a scale of 0.1 ml);
11. Constant temperature water bath.
Third, the measurement procedure in a 250 ml beaker, add 100 ml of 25 ~ 30 ° C standard hard water, pipette the emulsion sample, and slowly add to the hard water (according to the dilution concentration specified by each product) Formulated into 100 ml of emulsion. After the emulsion is added, continue to stir at 2-3 rpm for 30 seconds, immediately transfer the emulsion to a clean, dry 100 ml graduated cylinder, and place the cylinder in a constant temperature water bath at a temperature of 25 to 30 °C. After standing for 1 hour, take out and observe the separation of the emulsion. If there is no oil slick, oil or precipitate in the measuring cylinder, the stability is acceptable.
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Opening methods: Handing driving mode
Rope driving mode
Remote control driving mode
Electric switch driving mode
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