Quality standards for pesticide

1. The purity of the original purity of the drug in active ingredient content, expressed in percentage. Purity of the main indicators of the quality of the original drug, the higher the percentage of active ingredient content the better the quality. UN Food and Agriculture (FAO) and World Health Organization (WHO) reported pesticide quality standards should be more than 90% purity. Quality standards for pesticides in China, the original drug's purity has generally above 90%. Purity and low impurities in pesticide content to high, too many impurities in the original drug has the following hazards: 

     (1) crops may produce injury. Meihekou rice in Jilin Province in 2000 using the injury occurred Bensulfuron, resulting in rice seedlings died. Bensulfuron good for the safety of rice seedlings, generally will not produce injury. According to preliminary research shows that: produce injury because bensulfuron impurities in JP-003 JP-004 content and excessive. 

     (2) a lot of impurities will increase the original drug to human toxicity. For example, pure methamidophos LD50 in rats is 30mg/kg body weight, while some domestic manufacturers to produce 50% of the methamidophos EC LD50 in rats is 13.6mg/kg, that toxicity increased as a reason phosphorus crude amine in 5 of the high content of impurities, and the toxicity of these five kinds of impurities are more toxic methamidophos pure high. 

     (3) are all impurities in the original drug to the active ingredient molecules containing atoms of an element or a calculation of the amount of active ingredient content of the chemical analysis lose their accuracy. Because impurities in the active component also contains the same elements or groups of atoms, so that the results of the determination of bias, does not reflect the original drug and its preparations in the actual content of active ingredient. 

     (4) back to the original drug impurities in the powder processing difficult, because the presence of impurities in the original drug's freezing point depression and difficult to crush. 

     (5) of the original drug impurities can reduce the stability of active ingredients, and with the use of pesticides, impurities into the environment, causing pollution. So to maximize the purity of the original drug to reduce impurities. 

2. PH pH is not only the quality indicator is also the original drug preparation quality indicators. PH refers to the pesticide and its preparation containing free acid or free base number, or the hydrogen ion concentration. The main purpose of restriction is to lower the pH during storage of pesticide active ingredients and preparation decomposition, to prevent the preparation and its use to change the physical properties of phytotoxicity. In addition, pesticides can be used to assess the corrosion of the packaging materials for reference. FAO and the preparation of original drug quality standards and preparations are pH acidity (H2SO4 content in percentage) or alkalinity (NaOH content in percentage) that the general requirements of the original powder was <0.1% ~ 0.2% of the original powder and preparation PH value of the pH sometimes said. Of pesticide regulations on the acidity or alkalinity, said most of the provisions of the PH value of the preparations said. 

3. Moisture content and moisture content is both original drug preparation quality indicators. Restricted pesticides in the water content of the original purpose of powder is to reduce the decomposition of active ingredients to maintain chemical stability. Of powder, WP formulations in terms of restrictions can maintain a good moisture content the dispersion state of good dispersion when sprayed into the leaf surface. FAO in 1971 after the promulgation of quality standards for pesticides, the pesticide and cream, some soluble powder formulations are water content and other indicators, while the powder, wettable powder that is, without water content indicators. The moisture content of powder required for not more than 1.5%. However, due to processing of different types of powder used in packing, the water absorption is different, and some filler absorbent, even if the higher water content, does not affect the dispersion of powder; some fill water absorption is weak, even if the moisture content is not too high, will also affect the dispersion of powder, so as to ensure the control of water content in the dispersion of powder is not reliable way, with control of powder flow index dispersion of powder moisture content than the control methods more effective. In the powder pesticide formulations of the quality standards are not liquidity indicators, but with limited moisture control their dispersion.