Development of an Analytical Method Based on Accelerated Solvent Extraction, Solid-Phase Extraction Clean-Up, then GC–ECD for Analysis of Fourteen Organochlorine Pesticides in Cereal Crops

Modified QuEChERS Extraction and HPLC-MS/MS for Simultaneous Determination of 155 Pesticide Residues in Rice (Oryza sativa L.)

Rice (Oryza sativa L.) is the staple food of more than half of the world’s population. The main factors affecting the quality of rice include grain length, texture, stickiness, flavor, and aroma. Pesticides are intended for the protection of plant products from weeds, fungi, or insects. However, pesticides also result in negative effects such as environment disturbances, pest resistance and toxicity to both users and food consumers. The aim of this study was to conduct validation experiments of a method for the determination of multi-pesticides in rice, a model food of other cereals. A quick, easy, cheap, effective, rugged, and safe (QuEChERS) method was used for the extraction of pesticide residues from rice followed by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) with a triple quadrupole instrument using electrospray ionization. The analytical method has chromatography-tandem according to SANTE/11813/2017. The limit of quantification was 5 μg/kg. Recoveries for the 155 analyzed pesticides ranged between 77.1% for pirimiphos-ethyl and 111.5% for flutriafol and they were determined at 3 spiking levels. The proposed method was demonstrated to be quick, simple, precise, and accurate and allowed for evaluating the compliance of cereals samples with legislated maximum residue levels of pesticides in the European Union.

Spatial distribution of organochlorine and organophosphorus pesticides in soil-groundwater systems and their associated risks in the middle reaches of the Yangtze River Basin

Soil and groundwater samples were collected from paddy fields in the middle reaches of the Yangtze River Basin to study the occurrence and the risks associated with organochlorine pesticides (OCPs) and organophosphorus pesticides (OPPs) in soil and groundwater. Results showed that OCPs and OPPs were widely distributed throughout the study area. The levels of OCPs and OPPs in the soil were much lower than those specified by soil quality standards. However, the levels of four OCPs (heptachlors, aldrin, dieldrin, and γ-hexachlorocyclohexane) in groundwater were higher than those permitted by drinking water standards. The health risk assessment method suggested by the US Environment Protection Agency was used to evaluate the regional risks from selected pesticides. Results showed that there were low health risks from OCPs and OPPs in soil at the regional scale, but high risks from heptachlor, aldrin, and endrin in groundwater, suggesting an urgent need for groundwater protection. There are widespread concerns on dichlorodiphenyltrichloroethane and hexachlorocyclohexane, but little focus on other pesticides in China. However, our results suggest that the presence of, and risks from, other pesticides in groundwater should be a focus from the region aspect.

Comparison of Different Extraction Methods for Analysis of 10 Organochlorine Pesticides: Application of MAE-SPE Method in Soil from Beijing

Four commonly applied extraction techniques for organochlorine pesticides, microwave-assisted extraction (MAE), accelerated solvent extraction (ASE), quick, easy, cheap, effective, rugged, and safe (QuEChERS) extraction and ultrasonic solvent extraction, were applied on soil samples in order to evaluate their performances. The extracts were analyzed by GC-ECD and confirmed by GC-MS/MS. The MAE and QuEChERS extraction methods generally yielded higher results compared to the ultrasonication and ASE methods, while the lowest recovery (56.8 %) for o,p'-DDD was obtained using the QuEChERS method. The MAE method was further applied to six different soils from Beijing. In the soil samples only α-endosulfan and β-endosulfan were not detected. The ratios of α-HCH/γ-HCH and α-HCH/β-HCH indicated HCH residues likely originated from historical use of HCHs, and that technical HCHs were not likely being currently applied in Beijing.