An improved spot-test for the detection of paraquat and diquat in biological samples
1987; Elsevier BV; Volume: 167; Issue: 2 Linguagem: Inglês
10.1016/0009-8981(87)90375-5
ISSN1873-3492
Autores Tópico(s)Protein Interaction Studies and Fluorescence Analysis
ResumoThis chapter explores the chemical identity, toxicity, and usage of paraquat. Paraquat is usually formulated as the dichloride salt also known as methyl viologen. Code designations for the material are PP148 for the dichloride salt and PP910 for the bis salt. Paraquat dichloride forms colorless, hygroscopic crystals, which decompose at 300 °C. It is practically non-volatile with a vapor pressure of < 0.1 mPa. It is very soluble in water (700 g/l at 20 °C) and practically insoluble in most other organic solvents. It is mainly formulated as an aqueous solution with surface-active agents. It is used for broad-spectrum control of broad-leaved weeds and grasses in fruit orchards and plantations and for inter-row weed control in many crops. It is also used for general weed control on non-crop land, as a defoliant on cotton and hops, for destruction of potato haulms, as a desiccant, and for control of aquatic weeds. Paraquat is rapidly deactivated upon contact with the soil and does not leach. Following a lethal dose of paraquat to rats mortality is first seen on days 2–5 after dosing but deaths can also occur around days 10–12, indicating there is considerable inter-individual animal response to the chemical. The major cause of death after a median lethal dose (MLD) is due to lung damage. The MLD of pure paraquat dichloride expressed as the cation was about 150 mg/kg to female rats and ranged from 100–143 mg/kg in a number of different strains from a number of different laboratories. As in experimental animals, paraquat is not metabolized in humans, but is reduced to an unstable free radical, which is then re-oxidized to produce a superoxide radical. The therapy of paraquat intoxication has focused on three main areas: prevention of absorption from the gastrointestinal tract, enhancement of elimination of paraquat from the body, and therapy directed against the mechanisms of toxicity.
Referência(s)