How to identify the hidden components of pesticides

How to identify hidden components

In general, "special effects" drugs will have distinctive features, such as killing insects, preventing diseases, and removing grass.

For samples that require profiling, the price should first be provided, ie the price per ton, so that the sample can be given a preliminary position in the current pesticide market: whether it is a new drug or a pesticide of what kind.

Secondly, it should provide the object of control, which is used for insecticide, weeding or sterilizing. Which kind of pest, which kind of bacteria or which kind of grass is the insecticide? According to the type of pest control, the pesticide range is judged first. For example, cotton aphid, consider those acaricides. If you are killing cotton bollworm (Lepidoptera, Noctuidae), you should consider those insecticides that kill lepidoptera, such as chlorantraniliprole.

Third, the pharmacodynamic characteristics of pesticides. Different types of pesticides have different symptoms of poisoning. First, according to the symptoms of pest poisoning, the type of pesticide can be initially determined. If the pest is poisoned, curled, spit, or sputum, the sample may be an organophosphate insecticide. Secondly, according to the speed of insecticide, it is also an important basis to help identify the type of pesticide. For example, in insecticides, carbamates, pyrethroids, and organophosphorus have a faster insecticidal rate, while chitin inhibitors have slower efficacy and take 3 days to see the effect. Followed by the appearance, smell and the like of the pesticide. For example, organophosphorus has garlic, malodor or sulfur flavor. Pyrethroid insecticides can cause irritation to the human eye and skin. The symptoms of neonicotinoid insecticides such as acetamiprid and avermectin on armyworm poisoning are anesthesia, suspended animation, no shrinkage, no spitting, and active. The above characteristics can be used as a reference for qualitative pesticides.

Fourth, combined with simple bioassay, supplemented by sample qualitative, if it is an insecticide, it can be easily determined by three pests of armyworm, aphid and red spider. According to the efficacy, the prevention and treatment of the sample can be roughly judged. Direction, and then qualitative analysis of the instrument. It should be noted that the results of the stomach toxicity test of armyworms should be adhered to for 4 days, and the mortality rate should be calculated to prevent the leakage of chitin insecticides.

Schedule: Anatomy of some pesticides

Identification example

(1) "Special effect" emulsifiable concentrate of cotton aphid. This sample is a product sent from a large cotton grower and is a product without three. And told the species to kill insects fast. According to the experience of cotton aphid prevention and control, it is considered that it is possible to add highly toxic pesticides. It was determined by HPLC that there was a carbofuran inside.

(2) Analysis of cotton field herbicides . Three bags of samples, one large bag and two small bags. The big bag is labeled as quizalofop, and the other two pouches are marked as synergists. The control objects are grasses and broadleaf weeds. Quinoxaline is only effective against grass weeds, but not good for broadleaf weeds, and has no effect on cotton growth. The characteristics of its broadleaf weeds should be related to sulfonylurea herbicides. It is a sulfonylurea herbicide by HPLC analysis, and the other bag is a penetrant.

(3) Control of leaf miner insecticides. The label is avermectin. According to experience: avermectin itself has good control effect on leaf miner, and should also be an organophosphate insecticide. Analyzed by HPLC, there is one organophosphorus pesticide. Considering that most of the organophosphorus pesticides and avermectin are compounded, avermectin is decomposed, so the authors do not advocate the mixing of the two pesticides. In fact, avermectin has been decomposed in the analysis and the content does not reach the calibrated content.

(4) The special medicine for killing cotton bollworm - "two weeks of leisure." It is known that chlorantraniliprole has an outstanding effect on cotton bollworm, and it is also consistent with the price quoted. Analysis by HPLC showed that it was chlorantraniliprole, but its content was very low.

(5) Long-acting agents for controlling cotton blind mites. The active ingredient of the label is Bacillus thuringiensis (BT), indicating that it should be a set of certificates, and BT will not cure blindness at all. The actual analysis is a high level of fipronil.

(6) One spray three anti-Omethoate EC. The description can simultaneously control wheat bran, powdery mildew and dry leaves. Gas chromatography analysis reduces the decomposition of omethoate when using a large pore capillary column. The results showed that the omethoate had a low decomposition content, and at the same time, the added fungicide powder rusting was also left.

(7) Prevention and control of white powder emulsifiable concentrate. The cotton planting base of the Hejian Guoxin Agricultural Research Association sent it, saying that the effect of controlling whitefly is good. The active ingredients were analyzed by HPLC method, which were three kinds of pesticides, acetamiprid, alkaloid and avermectin.

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