Determination of pesticides and their degradation products in sediment samples by accelerated solvent extraction and solid-phase extraction with high-performance liquid chromatography-high-resolution mass spectrometry

Combination of atom transfer radical polymerization and alkyne-azide click-chemistry for the synthesis of phosphonic acid cation exchange materials

Phosphonic acid cation exchange materials (PCX) are synthesized by atom transfer radical polymerization (ATRP) followed by alkyne-azide click-chemistry. ATRP is used to synthesize polymeric chains of diethyl 4-vinylbenzylphosphonate with different chain lengths, which are covalently bonded to the surface of monodisperse polystyrene-divinylbenzene (PS/DVB) particles by click-chemistry. The functionalized particles are characterized by FIB-SEM, IR and Schoeniger combustion followed by chromatographic experiments. The effect of chain length on chromatographic behavior is investigated by comparing four PCX columns with different chain lengths. Polar ionic pesticides and non-polar triazines are used as model analytes for chromatographic characterization. The chain length showed an influence on the retention of doubly charged analytes, which can be explained by the increased local charge density with longer chains. The resolution of the constitutional isomers prometryn and terbutryn increased with the chain length, leading to an isocratic separation of seven triazines in 35 min. They also showed secondary interactions with the polymeric support material that are not influenced by capacity or chain length.

Multiresidue method for the fast and efficient analysis of current-use pesticides in streambed sediments using pressurized liquid extraction

A multiresidue method for the fast and efficient analysis of current-use pesticides in streambed sediments is reported. The method employs pressurized liquid extraction (PLE) for the automated extraction of pesticide residues from small quantities (5 g) of lyophilized sediment samples. Various PLE parameters, including the extraction solutions and oven temperature, were optimized for thirty diverse current-use pesticides (CUPs) known to be commonly applied to corn and soybean monoculture crops. Following extraction, samples were analyzed with a fast and simplified quantitative multiresidue analytical method using ultra high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) with online solid phase extraction (SPE) on a hydrophilic-lipophilic balance (HLB) column. Validation of the method demonstrated acceptable recoveries (avg 41.4 %) comparable with other multiresidue methods for sediments, reliable intraday (<13 %) and interday (<24 %) repeatability, reasonable matrix effects (avg -54 %), and low LODs (avg 0.53 ng g-1 dw) and LOQs (avg 2.18 ng g-1 dw) given the complexity of the sediment matrix. The method was applied to 119 streambed sediment samples collected from agriculture-adjacent headwater streams near Lac Saint-Pierre in Québec, Canada to demonstrate the utility of the method. Fourteen of the thirty target analytes were detected within the samples, including nine herbicides, two insecticides, and three fungicides. To the best of our knowledge, an equally simple and efficient multiresidue method for the quantitative analysis of diverse CUPs in streambed sediments using PLE and UHPLC-MS/MS with online SPE has not yet been reported in the literature. This method helps to reduce labour and material inputs, avoids excessive sample manipulation, and allows for fast quantitative analysis of trace pesticide residues in streambed sediments, with the potential for application to other contaminants of emerging concern.

Review of scientific literature on available methods of assessing organochlorine pesticides in the environment

Organochlorine pesticides (OCPs) are persistent organic pollutants (POPs) widely used in agriculture and industry, causing serious health and ecological consequences upon exposure. This review offers a thorough overview of OCPs analysis emphasizing the necessity of ongoing work to enhance the identification and monitoring of these POPs in environmental and human samples. The benefits and drawbacks of the various OCPs analysis techniques including gas chromatography-mass spectrometry (GC-MS), gas chromatography-electron capture detector (GC-ECD), and liquid chromatography-mass spectrometry (LC-MS) are discussed. Challenges associated with validation and optimization criteria, including accuracy, precision, limit of detection (LOD), and limit of quantitation (LOQ), must be met for a method to be regarded as accurate and reliable. Suitable quality control measures, such as method blanks and procedural blanks, are emphasized. The LOD and LOQ are critical quality control measure for efficient quantification of these compounds, and researchers have explored various techniques for their calculation. Matrix interference, solubility, volatility, and partition coefficient influence OCPs occurrences and are discussed in this review. Validation experiments, as stated by European Commission in document SANTE/11813/2017, showed that the acceptance criteria for method validation of OCP analytes include ≤20 % for high precision, and 70-120 % for recovery. This may ultimately be vital for determining the human health risk effects of exposure to OCP and for formulating sensible environmental and public health regulations.