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Determination of Pesticides in Soil
Published in José L. Tadeo, Analysis of Pesticides in Food and Environmental Samples, 2019
Beatriz Albero, Rosa Ana Pérez, José L. Tadeo
This compound is very polar and has a high solubility in water so direct determination by GC is difficult. In addition, the lack of chromophores or fluorophores in its chemical structure makes impossible its analysis by LC using ultraviolet (UV) or fluorescence detection. In the GC analysis of glyphosate and its main metabolites, isopropyl chloroformate or the mixture of trifluoroacetic anhydride and trifluoroethanol are used as derivatizing agents [79]. Derivatives for LC determination are prepared using pre- or postcolumn reactions to improve the pesticide response. In postcolumn derivatization, the reaction is produced with o-phthalaldehyde (OPA) and mercaptoethanol, but 9-fluorenylmethyl chloroformate (FMOC-Cl) is used in precolumn derivatization, to form fluorescent derivatives with an improvement in the chromatographic determination [5].
An Insight into Green Microwave-Assisted Techniques
Published in Banik Bimal Krishna, Bandyopadhyay Debasish, Advances in Microwave Chemistry, 2018
Natalia A. Gomez, Maite V. Aguinaga, Natalia Llamas, Mariano Garrido, Carolina Acebal, Claudia Domini
A MA-DLLME method with the addition of surfactant was developed to perform a one-step derivatization and extraction of aminoglycosides in milk samples [162]. The derivatization is performed in order to turn the analytes into fluorescent compounds. On the other hand, the surfactant accelerated the dispersion of the extraction solvent into the aqueous sample and decreased the time of analysis. Thus, a mixture of 100 µL of a 0.20 mmol L−1 Triton X-100 solution, 60 µL of [C6MIM][PF6] ionic liquid, used as the extraction solvent, and 50 µL of 2.5 mmol L−1 of 9-fluorenylmethyl chloroformate solution, used as derivatization reagent, was injected into 5.00 mL of the sample. Then, the sample was irradiated in a modified household microwave oven at 180 W for 60 s to achieve the derivatization and extraction of the analytes. The IL phase was separated from the bulk solution, diluted with acetonitrile and injected into a HPLC instrument. The variables of the extraction were exhaustively optimized, taking into account the highest extraction recoveries.
Herbicides: Glyphosate
Published in Pradyot Patnaik, Handbook of Environmental Analysis, 2017
Immunosensors have been successfully applied for measuring GLYPH in water and soil (Clegg et al., 1999; Gonzalez-Martinez et al., 2005; Lee et al., 2002). Gonzalez-Martinez et al. (2005) have described a fully automated immunosensor for measuring GLYPH in water and soil. Their method involves carrying out an online derivatization reaction of GLYPH prior to assay and uses a selective anti-GLYPH serum, a GLYPH peroxidase enzyme-tracer, and a fluorescent detector. The assay time is stated to be 25 min and the detection limit 0.02 μg/L. Such a sensor can be reused over 500 analytical cycles. The procedure described by Lee et al. (2002) uses succinic anhydride to derivatize GLYPH mimicking epitotic attachment of GLYPH to horseradish peroxidase hapten. Such immunoassay measurement proceeds through an effective derivatization process and the method exhibits a high degree of precision and accuracy comparable to that obtained in a nonimmunoassay method such as the one involving HPLC/MS detection after derivatizing the analyte online on the SPE cartridge with 9-fluorenylmethyl chloroformate.
Herbicide determination in Brazilian propolis using high pressure liquid chromatography
Published in International Journal of Environmental Health Research, 2021
M. A. Umsza-Guez, N. P. Silva-Beltrán, B. A. S. Machado, A. P. Balderrama-Carmona
The extraction method for the determination of glyphosate, picloram and AMPA was the following: Propolis (1 g) was weighed in a glass flask and suspended with 6 mL of methanol for 24 h at 25°C; after this time, the samples were shaken for three minutes and centrifuged at 2031 xg for 10 min. The supernatants were purified by filtration through a cellulose acetate membrane of 0.45 μm (MF-MilliporeTM); next, the extract obtained was diluted 1:100 of HPLC water (Sigma-Aldrich, 270,733). Derivatization was performed by mixing 3 mL of purified sample and 2 mL of 9-fluorenylmethyl chloroformate (FMOC-Cl) (0.005 M) (23,186 Sigma-Aldrich, MO, U.S.A.) prepared with chloroform (650,498 Sigma-Aldrich, MO, U.S.A.). The solution was maintained for 45 min in the dark. After the reaction, 3-mL methyl chloride (270,997 Sigma-Aldrich, MO, U.S.A.) was added to remove excess of FMOC-Cl; subsequently, the supernatant was filtered using solid-phase extraction (SPE) polymeric columns (Strata C-18 Phenomex, 8B-S001-HCH-T, Torrance, CA, U.S.A.) for the extraction of polar organic substances in aqueous matrices (Olivo et al. 2015), and the C18 cartridges were preconditioned with 5 mL methanol followed by 5 mL of water (prefiltered with 20 µm cellulose acetate membrane). The fluid obtained was reserved for the HPLC analysis.
Efficient degradation of organic phosphorus in glyphosate wastewater by catalytic wet oxidation using modified activated carbon as a catalyst
Published in Environmental Technology, 2018
Bo Xing, Honglin Chen, Xiaoming Zhang
9-Fluorenylmethyl chloroformate (FMOC-Cl), PMG (99.1%), and AMPA (99.5%) reference standards were purchased from Aladdin Industrial Corporation. H2O2 (30%), ethyl ether, acetonitrile, hydrogen nitrate, sulfuric acid, acetic acid, and acetylacetone were analytical grade and obtained from Guangdong Guanghua Sci-Tech Co., Ltd. Potassium dihydrogen phosphate, sodium tetraborate, melamine, and ammonium acetate were analytical grade and obtained from Chengdu Kelong Chemical Reagent Factory. Other reagents used for the analysis of TP, , chemical oxygen demand (COD), , and were analytical grade and purchased from Sinopharm Chemical Reagent Co., Ltd.
Urinary glyphosate biomonitoring of sprayers in vegetable farm in Thailand
Published in Human and Ecological Risk Assessment: An International Journal, 2021
Sasivimol Bootsikeaw, Pornpimol Kongtip, Noppanun Nankongnab, Suttinun Chantanakul, Dusit Sujirarat, Redeerat Mahaboonpeeti, Phanthawee Khangkhun, Susan Woskie
Glyphosate (N-(phosphonomethyl)glycine) and DL-2-amino-3-phosphonopropionic acid (APPA; internal standard) and acetonitrile, for high performance liquid chromatography (HPLC), gradient grade, >99.9% were obtained from Sigma-Aldrich (Singapore). In addition, 9-fluorenylmethyl chloroformate (FMOC-Cl), 99.0% for HPLC was purchased from Fluka (Buchs, Switzerland). Ammonium formate (99%) was purchased from Fisher Scientific (Spain). Sodium tetraborate was purchased from Thermo Fisher Scientific (Albany, Auckland, New Zealand). Ultrapure water was obtained from a Milli-Q system (Millipore, Bedford, MA, USA) while other chemicals were analytical reagent grade (AR).