Degradation study of benomyl and carbendazim in water by liquid chromatography and multivariate curve resolution methods

Abstract

The degradation of benomyl and carbendazim in different organic solvents, distilled and ground waters was studied by on-line solid-phase extraction (SPE) followed by liquid chromatography (LC), diode array detection (DAD) or atmospheric pressure chemicalionization mass spectrometry detection (APCI-MS), UV spectrophotometry and multivariate curve resolution. Stability studies were performed in different organic solvents, such as acetonitrile and methanol, and in aqueous solution at different pH. Samples were stored in dark conditions at 4 ~ and analysed by LC-DAD over 10 days. Photodegradation products of benomyl were resolved by spectrophotometry and multivariate curve resolution between pH 3 to 9. These results were correlated with those from LC-DAD and LC-APCI-MS. Photolysis studies were carried out at low concentration levels (2 lag L -1) of carbendazim under different storage conditions in order to evaluate the effect of parameters, such as pH, temperature and sunlight exposure. Water samples (50 mL) were preconcentrated using on-line SPE-LC-DAD. Photodegradation products of benomyl and carbendazim were identified by on-line-SPE-LC-DAD and SPE-LC-APCI-MS, leading to identification of carbendazim, 3-butyl-2,4-dioxo-s-triazinol,2-abenzimidazole (STB) and 2-aminobenzimidazole (2-AB).

Analysis of Benomyl by Liquid Chromatography/Time-of-Flight Mass Spectrometer and Its Occurrence in the Environment

“…6 According to the Japanese Speed 98, MDLs for water, soil, and biota samples are 0.1 µg/L, 2 µg/kg, and 20 µg/kg, respectively. 7 Our sample treatment for benomyl analysis in water was carried out according to U.S. EPA-631 method except concentration ratio. According to U.S. EPA-631 method, 500 mL of water was taken and concentrated to final volume of 10 mL.…”

“…It is known that the compound is intact at least 8 days at pH 8 in water. 5,7 Due to these behaviors, the direct measurement of benomyl concentration is not feasible, but indirect method, determination of carbendazim concentration, is widely accepted. The concentration of carbendazim is transformed to benomyl concentration by multiplication of molecular ratio of benomyl to carbendazim.…”

Interpretation and modelling of environmental behaviour of diverse pesticides by revealing photodecomposition mechanisms

“…Three products were detected after the UV irradiation. One of them, 2,4-amino-benzimidazol has already been identified in a previous paper (Mallat et al, 1997, Tomlin, 1994. A plausible pathway for the photolytic degradation of carbendazim in pure water was proposed as well, however our studies pointed out marked differences when comparing the two different mechanisms.…”

Rapid determination of fungicides in fruit juices by micellar electrokinetic chromatography: Use of organic modifiers to enhance selectivity and on-column high-salt stacking to improve sensitivity

“…Interest in their separation and determination in food samples has risen considerably in recent years due to their proven or suspected toxicity [1,2]. Thus, these pesticides are monitored in a wide variety of agricultural commodities [2,7], and maximum residue limits (MRL) in foods have been set by international organizations; for example, the European Commission imposes MRL between 0.1 and 10.0 mg/kg, depending on the specific fungicide and the crop type [8].…”