Carbamate degradation products

Degradation products of carbamate insecticides [18] e.g. mexacarbates, matacil, landrin... 

Phenazone (182) was shown to be more photostable than amidopyrine or sulpyrine [116] however, several publications describe a number of photo-degradation products. After irradiation in methanol with a medium-pressure mercury lamp for 70 h, Ege isolated the carbamate (183,20%), the imidazolone... 

Carbamates are most frequently absorbed by inhalation, ingestion, or dermal penetration, and actively metabolized via the liver. Their degradation products are excreted by both the kidneys and liver. 

N-methyl carbamates are absorbed by inhalation and ingestion and some by skin penetration. Dermal absorption of particular compounds (notably carbofuran) is very slight. N-methyl carbamates are hydrolyzed enzymatically by the liver and the degradation products are excreted by the kidneys and the liver. 

Acid/base stress testing is performed to force the degradation of a drug substance to its primary degradation products by exposure to acidic and basic conditions over time. Functional groups likely to introduce acid/base hydrolysis are amides (lactams), esters (lactones), carbamates, imides, imines, alcohols (epimerization for chiral centers), and aryl amines. 

Very few studies have reported on the stability of herbicides, including triazines and degradation products, on SPE materials.In addition to time and space savings, the stabihzation of pesticides on these materials makes it possible to use SPE techniques for onsite extraction. Sabik et al. demonstrated the stabihty of 20 urea and triazine herbicides, including four degradation products, on GCB material over a two month period. LiSka and Bilikova studied the stabihty of 16 polar pesticides including triazines, carbamates, and phenylureas sorbed on to a polymer sorbent. They found that most of these remained stable over a seven-week period. Crescenzi... 

Aldicarb nitrile (12), a residual degradation product of the carbamate pesticide Aldicarb, can be analysed by GC using a short column and MS detection, with a detection limit of 0.15 ng. The short column is required to avoid thermal degradation of Aldicarb to 12 that could distort the analysis . 

The carbamate pesticides aldicarb, carbaryl and their degradation products, aU under research in photochemical degradation studies, were characterised by TSP-LC-MS and MS/MS. A tentative photodegradation pathway for the different pesticides in water was postulated [256]. 

The degradation of the carbamates carbofuran and methiocarb in estuarine waters was compared with that of aqueous samples exposed to UV fight in the laboratory. TSP- and ESI-LC-MS were used for product monitoring and identification of degradation products. The predominant degradation pathways observed here. 

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