GB/T 38793-2020Technical specification of efficacy evaluation for degradation of heterocyclic pesticides by biological products (English PDF)

4.4 Receiving, storage, handover, preparation, recycling, and returning/disposal of

samples shall be carried out in accordance with relevant laws, regulations, and standards;

corresponding management systems and procedures shall be formulated.

4.5 There shall be professional and technical personnel suitable for efficacy evaluation.

4.6 The environmental conditions of the laboratory shall meet the evaluation requirements, and the laboratory carrying out microbial evaluation shall meet the requirements of grade-I biosafety.

4.7 The type, quantity, performance, range, and accuracy of instruments and equipment

used in efficacy evaluation shall be able to meet the needs of efficacy evaluation. The utensil materials required for the efficacy evaluation of microbial products shall be aseptically treated.

4.8 The reagents used for efficacy evaluation shall be analytical grade, and the water shall comply with the grade II water specified in GB/T 6682.

4.9 The purity of the standard heterocyclic pesticides selected for efficacy evaluation

shall be greater than or equal to 95%; the culture medium shall be selected according to the type of microorganism.

4.10 After the experiment is over, the experimental materials shall be treated harmlessly to ensure the cleanliness and safety requirements of the experimental environment.

5.1 Experimental design

It shall meet the requirements of Table 1.

temperature, dissolved oxygen (shaking speed), and time, should be selected to determine the reaction system.

5.5 Degradation treatment

5.5.1 Microbial product degradation treatment

Take 9 Erlenmeyer flasks of 250 mL, including 3 blank samples, 3 test samples, and 3 inactivated samples. According to the substrate concentration and amount of microbe added determined by the optimal reaction system, a culture solution with a reaction system of 100 mL is prepared, and the degradation reaction is carried out under the conditions of the optimal reaction system.

5.5.2 Enzyme product degradation treatment

Take 9 centrifuge tubes of 50 mL, including 3 blank samples, 3 test samples, and 3 inactivated samples. According to the substrate concentration and the amount of enzyme added determined by the optimal reaction system, a reaction solution with a reaction system of 15 mL is prepared, and the degradation reaction is carried out under conditions of the optimal reaction system.

6.1 Determination of substrate concentration

After the degradation treatment is over, take 15 mL of the reaction solution, and determine the concentration of the substrate according to the provisions of GB 21523.

6.2 Calculation of degradation rate

It is calculated according to formula (1):

where:

R -- degradation rate, %;

Xi -- the original mass concentration of the substrate, in milligrams per liter (mg/L);

Xa -- the mass concentration of the substrate at the end point of the degradation reaction of the test sample, in milligrams per liter (mg/L);

Xb -- the mass concentration of the substrate at the end point of the degradation reaction of the inactivated sample, in milligrams per liter (mg/L);

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