GC-MS fragmentation patterns of sprayed endosulfan and its sulphate metabolite in samples of Theobroma cacao L from a field kinetic study

Abstract

Most environmental analytical methods for the determination of organochlorine pesticides (OCPs) are multi-residual with other organic compounds co-extracted and co-eluted. This has been observed in GC spectra using classical detectors like electron-capture detector (ECD) even after appropriate clean-up. This limitation could be resolved by using GC-MS methods which are more specific and selective. Thus, a commercial-grade endosulfan treated Theobroma cacao plantation was sampled. Representative samples comprising leaves, stem bark and pulp were obtained between 0.5 h and 60 days after treatment. Samples were analyzed for residual parent endosulfan ( α- and β-isomers) as well as the metabolite endosulfan sulphate using an ion trap GC-MS. The retention times and chromatogram peaks obtained for various endosulfan were identified and compared with reference standards, and confirmed with National Institute of Standards and Technology library. Results showed that the molecular ion at m/z 407 was exhibited by α- and β-endosulfan, representing the parent molecular ion M+• ([C9H6Cl6SO3]+•). The α-isomer was more thermally stable, hence exhibited more relative abundance. Other predominant peaks were 339, 307, 277, 265, 243, 241, 207, 195, 160, 159, 99 and 75 m/z. The peak at m/z 159 was the base molecular ion. For endosulfan sulphate, the peak at m/z 422 corresponded to parent molecular ion (M+•), while m/z 424 was due to isotopic pattern characteristic of the chlorine atom. The peaks at 387, 357, 289, 272, 229, 206, 170, and 120 m/z were characteristic for the sulphate metabolite. The m/z peak at 272 was the base molecular ion, while m/z 143 may be due to metabolite diol and lactone. These results showed that the various endosulfan species can be identified and confirmed simultaneously using a GC-MS.

Kinetic field dissipation and fate of endosulfan after application on Theobroma cacao farm in tropical Southwestern Nigeria

“…Also, identified peaks for α-endosulfan, β-endosulfan and endosulfan sulfate obtained for each matrix was confirmed by selected molecular ion peaks at m/z values using the National Institute of Standards and Technology (NIST) search library (Stein 1995, Vaikosen et al, 2018).…”

Kinetic and isotherm studies on the adsorption–desorption of technical-grade endosulfan in loamy soils under Theobroma cacao L cultivation, Southwestern Nigeria

“…These m/z spectra patterns are characteristic of endosulfan. 15,47 Also, Figures 4 (a -j) represents chromatograms (with peak areas/heights) of both isomers from t 0 -t 480 , -these indicates the amount of residual endosulfan in 0.01 M CaCl 2 medium at working time amplitudes as the soilendosulfan reaction progresses. A decrease in the amount of residual endosulfan implied an increase in the amount of pesticide adsorbed to soil samples.…”

Metals and Antibiotics as Aqueous Sequestration Targets for Magnetic Polyamidoamine-Grafted SBA-15

“…Water contamination is an issue of important concern because water is a vital factor in the global burden of disease and food security. Major contaminants of concern include toxic elements and several organic contaminants such as polycyclic aromatic hydrocarbons (PAHs) , and persistent organic pollutants (POPs) . Recently, naturally originating contaminants finding their ways into water sources have been enormously supplemented from anthropogenic activities. − Of serious concern are emerging water contaminants especially pharmaceuticals and personal care products (PPCPs), as well as agro-allied and related chemicals. − With the continued rise in global population, the concentrations of these contaminants in the environment, especially in water, will increase accordingly.…”

“…Major contaminants of concern include toxic elements and several organic contaminants such as polycyclic aromatic hydrocarbons (PAHs) , and persistent organic pollutants (POPs) . Recently, naturally originating contaminants finding their ways into water sources have been enormously supplemented from anthropogenic activities. − Of serious concern are emerging water contaminants especially pharmaceuticals and personal care products (PPCPs), as well as agro-allied and related chemicals. − With the continued rise in global population, the concentrations of these contaminants in the environment, especially in water, will increase accordingly. Specific contaminants in these groups include antibiotics, such as ciprofloxacin and tetracycline, and some toxic elements associated with pesticides and fertilizers, such as As and Cd.…”

“…Major contaminants of concern include toxic elements and several organic contaminants such as polycyclic aromatic hydrocarbons (PAHs) 1,2 and persistent organic pollutants (POPs). 3 Recently, naturally originating contaminants finding their ways into water sources have been enormously supplemented from anthropogenic activities. 1−4 Of serious concern are emerging water contaminants especially pharmaceuticals and personal care products (PPCPs), as well as agro-allied and related chemicals.…”