Pesticide residue test registration criteria (China)

First, the principle of field trials
1. Field residue trials must use pesticides in two representative areas of two-year trial, the two crop growing conditions the region has some representation (not necessarily a control test to the object exists).
2. Test crop varieties, cultivation methods, pesticide application history and weather conditions should be clear.
3. Experimental plot size varies with the crops, the area must ensure that there can be repeated to obtain a representative sample of the protected area is located between the lines, residential area of ​​generally 30 square meters (depending on the crop may be appropriate to increase or decrease), fruit less than 2. Each treatment area is located more than 3 repeated.
4. Pesticide control area must be located not necessary in the control zone can be used for pharmaceutical testing of pesticides without interference.
5. Medication must be registered test products, in accordance with the recommended dose and method of spraying. Test should be at least two doses of medication, one is the recommended maximum dose, another dose as the case may be, if the injury does not occur, use the recommended dose (or amount used) of 1.5 to 2 times the dose . Spraying should be based on the number of times and higher than the recommended number of times the recommended spraying.
6. The use of local agricultural production should be used on the Medical Device and recommended way to pesticide spraying.

Second, the field trial design
1. Should be designed to test the amount of spraying, spraying the number of random permutations during spraying test plot is located to clear crop residue with the relationship, and to develop standards for safe use.
2. In order to clarify the trend of pesticide residues in digestion, measured half-life, dynamic tests should be done digestion residue.
(1) of rice, wheat, fruit trees and other crops harvested during the same period, should be set at various times of the spraying process.
(2) of the crops harvested at different times (such as cucumber, tea, tobacco, etc.) should be set once a pesticide test sample stage.
(3) If the spraying times, the last time immediately after spraying droplets dry samples measured after different intervals and then sampled, measured at least five times. Usually the last residues of digestion in> 90% of the sample.

Third, the sampling
Standardization of sample collection is to obtain accurate data base. Since the actual field use of pesticides can not spreading evenly, requires that the sampling must be random and representative, and must be taken in sufficient quantities, or else, nor even the most accurate determination of the actual meaning. Avoid collecting sick, too small or immature crop samples, and packaging, to fasten the label immediately to the residue laboratory.
1. Various crops in the sample volume
(1) cereal crops, such as: rice, wheat, miscellaneous cereals. Grain samples in each experimental plot randomized, multi-point (not less than 10 points) picked derived off grain, crude samples collected 5 to 10 kg, and then take 1 to 2 kg as the sample. Stems from such samples must be cut to 10 cm, each test plot 5 to 10 sampling points, sampling about 1 to 2 kg (as the crop may be).
(2) vegetable roots, tubers, bulbs vegetables (such as carrots, potatoes, onions, etc.), randomized, multi-point sampling 2 to 5 kg, at least five major vegetable species, remove attached soil, can not be washed (beet sample with the same volume). Ye Rong, stems Levin, vegetables and fruit, more random samples 2 to 5 kilograms. Doucai class (with pods), sample 2 to 3 kg.
(3) fruits, apples, pears, peaches and other large fruit, fruit collected from the whole plant, pay attention to upper, lower, inside, outside, sun face, nightside even picking 5 kg. Grapes, strawberries and other small fruits, sampling 2 kg.
(4) stone fruits and seeds walnuts, chestnuts, sampling 1 to 2 kg. Cottonseed, harvest sampling of about 1 kg, and remove the lint. Sesame seeds, beans, sunflower seeds, peanuts are on the 1 to 2 kg.
(5), tea, tobacco sample 1 kg.
(6) control area sampling, must be measured to avoid pesticide contamination.
(7) the general reduction in the number of samples of the sample can be used continuously criss and cross, give up three equal portions, until you get the right number of samples. For apples, oranges, cabbage, watermelon and other large individual, can pay all laboratory samples.
2. Water samples: the amount taken as needed, generally more random sampling of each plot, mixed filtered to take 1000 ml.
3. Soil samples: According to the mobility of pesticides, usually in the arable layer of each plot (0-15 cm) to take 5 to 10 points, each point of 1 kg, and finally into a kind of reduction for each area (for some pesticides, but also stratified soil samples taken).

Fourth, the sample pretreatment
1. Collection of specimens, the nature of unstable pesticides (easy to break down), should be immediately determined. Some temporarily unable to determine when, according to the original stored in the 0 to a 5 0C and stored. If longer storage time, must be in a 20 0C under cryopreservation, because the cells have been destroyed frozen samples after thawing the samples must be analyzed immediately.
2. Residues in different parts of the sample there is a difference, therefore, to a unified analysis of parts, otherwise it will cause confusion. In principle, the edible and used as feed for the target site and soil analysis required before the sample pre-treatment (pesticides for paddy field, but also to determine the amount of residual water). Sample the following example:
(1) rice, ground brown rice and then crushed to 40 mesh or so higher residual white rice samples should be measured. Beans, wheat, crushed to 40 mesh (crushed ice should be added to prevent decomposition and loss of pesticides). Straw, rice husk, straw and crushed to 40 mesh drum skin (green straw, wheat straw, cut into 1 to 2 cm length).
(2) apples, pears. Peaches, persimmons, cherries, etc., stalks and inner core or nucleus, is not peeled. Tomatoes, strawberries, eggplant, pepper, stalks. Citrus, pulp and peel were measured. Watermelon, cantaloupe, rind and flesh were measured. Banana, remove the peel.
(3) cabbage, Chinese cabbage, Geba, etc., remove the outer layer of old leaves. Onions, green onions, remove the old skin and fibrous roots. Radish, turnip, beet, carrot, ginseng, potato, taro, etc., to remove attached soil, but do not wash. Cucumber, remove the handle; pumpkins, stalks; spinach, remove the fibrous roots (left red).
(4) other issues such as peanuts, remove the skin; hops, dried; tea into tea; tobacco, baking or drying.

V. Analysis
1. General analysis of pesticide active ingredients only, some have clearly toxic degradation or transformation products, metabolites and impurities have to be determined.
2. Sensitivity and recovery
(1) The method is sensitive to the sample detection limit (minimum concentration detector ppm) said. Required detection limit than the allowable residues of at least one order of magnitude. Coefficient of variation requested: l ~ 10ppm ± 10% 0.1 ~ 1ppm ± 20% 0.01 ~ 0.1ppm ± 50% 0.001 ~ 0.0lppm ± 100 ~ 200%
(2) The recovery is generally to allow residues, below and above the permitted concentration of residues do recoveries, recoveries should be 70 to 110%, the general average of 80% or more.

Sixth, the results of sorting
(1) measurement results are generally measured value should not lose control samples, nor shall be corrected according to recovery.
(2) significant figures retained to be consistent (same report).
(3) The measured value does not meet the detection limit, should be "<detection limit", "trace" or "not detected" means.
(4) residual test summary report should include the field test design, analysis, sensitivity, recovery experiments to determine the results and chromatogram (HPLC method).
(5) residual test summary report must be engineers (or equivalent title) or more officers sign the test unit seal.

 

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