Abstract The transformation of the fungicide carbendazim (methyl-2 benzimidazole carbamate) induced by hydroxyl radical generated by the UV photolysis of H 2O 2 has been studied in dilute aqueous solution. The efficient reaction of hydroxyl radicals with carbendazim led to the rapid degradation of carbendazim. The study of reaction kinetics yielded a second order rate constant of 2.2±0.3 10 9 M -1 s -1for HO · radicals with carbendazim. This value is in agreement with a high reactivity of HO · radicals with carbendazim. Most degradation products were identified by high performance liquid chromatography mass spectrometry (HPLC-MS). In the presence of hydrogenocarbonate and carbonate ions, hydroxyl radicals were quenched and in turn carbonate radicals CO 3 ·- were formed. Carbonate radicals are indeed known to react efficiently with compounds containing electron-rich sites such as nitrogen or sulfur atoms. The use of a kinetic modelling software gave evidence for the occurrence of such reactions with carbendazim. The second order rate constant of carbonate radical with carbendazim was equal to 6±2 10 6 M -1 s -1.
Abstract
In this application note, capsaicins are used as a model for compounds difficult to resolve with flash chromatography. Capsaicin compounds possess very similar structures making them difficult to resolve from each other. Although these compounds can be resolved on flash chromatography columns, such as the RediSep® Rf Gold C18, preparative high pressure liquid chromatography (prep HPLC) can provide improved resolution due to their smaller particle size and better packing compared to Flash columns....
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Filtering organic solvents for applications such as HPLC buffer prep can be challenging in order to ensure chemical compatibility with filters (PVDF, Nylon, or PTFE), preserving longevity of an HPLC column, or containment of toxic fumes, but finding a suitable and comprehensive vacuum system is now easier than ever.
Sterlitech is now offering a comprehensive benchtop vacuum system, the Rocker-VF12 Kit, targeted to the purification of organic or corrosive liquids such as mobile phase solvents for HPLC analysis....
Reveleris® Prep: Purification with flash chromatography followed by a prep-HPLC isolation of citral isomers
Lemongrass is cultivated around the world. It`s mainly grown for its oils, which have a number of uses including for vitamin A, perfumes, insect spray, cosmetics, perfumes, food and drinks. Lemongrass is also enjoyed as a tea throughout the world. Lemongrass oil contains several monoterpenes, with citral being the major component, present at levels between 65-85%. Citral (3,7-dimethyl-2,6- octadienal)...
AbstractA high performance liquid chromatography (HPLC) method with a Corona Charged Aerosol detector for the cleaning validation of MICRO* A07 Citric Acid Cleaner residue has been developed. The pooled average repeatability of 3 replicates at 6 concentration levels expressed as RSD was 1.3 % while the pooled average intermediate precision (intra-day repeatability in 3 days) of 3 replicates at 6 concentration levels was 2.4 %. Simulated maximum allowable carryover (MAC) was calculated by using 10 ppm of MICRO®...
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