Dispersive-Solid-Phase Extraction Cleanup Integrated to Dispersive Liquid-Liquid Microextraction Based on Solidification of Floating Organic Droplet for Determination of Organochlorine Pesticides in Vegetables

Established and emerging organophosphate esters (OPEs) and the expansion of an environmental contamination issue: A review and future directions

The list of organophosphate esters (OPEs) reported in the environment continues to expand as evidenced by the increasing number of OPE studies in the literature. However, there remains a general dearth of information on more recently produced and used OPEs that are proving to be emerging environmental contaminants. The present review summarizes the available studies in a systematic framework of the current state of knowledge on the analysis, environmental fate, and behavior of emerging OPEs. This review also details future directions to better understand emerging OPEs in the environment. Firstly, we make recommendations that the current structural/practical abbreviations and naming of OPEs be revised and updated. A chemical database (CDB) containing 114 OPEs is presently established based on the suspect list from the current scientific literature. There are 12 established OPEs and a total of 83 emerging OPEs that have been reported in human and/or biota samples. Of the emerging OPEs more than 80% have nearly 100% detection frequencies in samples of certain environmental media including indoor air, wastewater treatment plants, sediment, and fish. In contrast to OPEs considered established contaminants, most emerging OPEs have been identified more recently due to the more pervasive use of high-resolution mass spectrometry (HRMS) based approaches and especially gas or liquid chromatography coupled with HRMS-based non-target analysis (NTA) of environmental sample fractions. Intentional/unintentional industrial use and non-industrial formation are sources of emerging OPEs in the environment. Predicted physical-chemical properties in silico of newer, molecularly larger and more oligomeric OPEs strongly suggest that some compounds such as bisphenol A diphenyl phosphate (BPA-DPP) are highly persistent, bioaccumulative and/or toxic. Limited information on laboratory-based toxicity data has shown that some emerging OPEs elicit harmful effects such as cytotoxicity, development toxicity, hepatotoxicity, and endocrine disruption in exposed humans and mammals. Established, and to a much lesser degree emerging OPEs, have also been shown to transform and degrade in biota and possibly alter their toxicological effects. Research on emerging OPE contaminants is presently limited and more study is warranted on sample analysis methods, source apportionment, transformation processes, environmental behavior, biomarkers of exposure and toxicity.

Solid-phase microextraction of eleven organochlorine pesticides from fruit and vegetable samples by a coated fiber with boron nitride modified multiwalled carbon nanotubes

A boron nitride modified multiwalled carbon nanotube material (BN@MWCNTs) was synthesized, and the synthesis conditions were optimized. The BN@MWCNTs was then used as the SPME fiber coating adsorbent for the extraction of eleven organochlorine pesticides (OCPs) from fruit and vegetable samples. Under the optimal conditions, the SPME coupled with the detection by GC-ECD had a linear response for the determination of the target analytes in the range of 0.03 to 200 ng g^-1 with the coefficients of determination (r²) ≥ 0.9977. Based on the signal-to-noise ratios of 3 and 10, the limits of detection and the limits of quantification were measured to be 0.01-0.20 ng g^-1 and 0.03-0.67 ng g^-1, respectively. The relative recoveries of the analytes for spiked samples under three concentration levels (1.0, 10.0 and 100 ng g^-1) were between 83.7% and 124% with the relative standard deviations ≤ 10.9%. The established method was successfully applied to the determination of OCPs in real fruit and vegetable samples.

Determination of Organochlorine Pesticides in Green Leafy Vegetable Samples via Fe3O4 Magnetic Nanoparticles Modified QuEChERS Integrated to Dispersive Liquid-Liquid Microextraction Coupled with Gas Chromatography-Mass Spectrometry

A fast method based on Fe₃O₄ magnetic nanoparticles (Fe₃O₄ MNPs) modified QuEChERS integrated to dispersive liquid-liquid microextraction (DLLME) coupled with gas chromatography-mass spectrometry was established for the determination of 8 organochlorine pesticides (OCPs) in green leafy vegetables. The factors involved in the purification by QuEChERS and concentration by DLLME were optimized. In the QuEChERS process, Fe₃O₄ MNPs were used as a new impurity adsorbent after the sample extraction procedure by acetonitrile, which achieved phase separation rapidly. Carbon black was used as an alternative to costly graphitized carbon black without affecting the recovery. In the process of DLLME, 1 mL of the extract obtained by QuEChERS was used as the dispersive solvent, 40 μL of chloroform was used as the extractive solvent, and 4 mL of water was added. Making them mix well, then the dispersed liquid-liquid microextraction concentration was subsequently carried out. The enrichment factors of 8 OCPs ranged from 22.8 to 36.6. The recoveries of the proposed method ranged from 78.6% to 107.7%, and the relative standard deviations were not more than 7.5%. The limits of detection and limits of quantification were 0.15-0.32 μg/kg and 0.45-0.96 μg/kg, respectively. The method has been successfully applied to the determination of OCPs in green leafy vegetable samples.

Human Risk Assessment of Organochlorine Pesticide Residues in Vegetables from Kumasi, Ghana

The use of organochlorine pesticides has been banned worldwide due to their toxicities. However, some farmers use them illegally because of their potency. The aim of this study was to assess the level of organochlorine pesticide (OCP) residues and the potential health risk associated with vegetables, soil, and groundwater obtained from farms in Ayigya, Nsenie, Gyenyase, and Kentinkrono in Kumasi, Ghana. A total of 15 samples were analyzed using a gas chromatograph equipped with an electron capture detector. The highest mean concentration of 184.10 ± 12.11 µg/kg was recorded for methoxychlor in cabbage from Ayigya. Beta-hexachlorocyclohexane (beta-HCH) recorded the lowest mean concentration of 0.20 ± 0.00 µg/kg in cabbage from Ayigya. The combined risk index showed significant health risk to children than adults. The soil samples mainly contained methoxychlor followed by dichlorodiphenyltrichloroethane (DDT), aldrin, and other OCPs. Concentrations of total HCHs, total DDTs, and total OCPs in the soil samples ranged from <0.01 to 49.00, <0.01 to 165.81, and <0.01 to 174.91 µg/kg, respectively. Among all HCH and DDT isomers, only β-HCH and p,p′-DDT were detected in some of the water samples. Carcinogenic risk values for β-HCH, aldrin, and p,p′ DDT in the groundwater were found to be >10−6, posing a potentially serious cancer risk to consumers. Moreover, the hazard quotients (HQs) of aldrin exceeded the threshold value of one, indicating that daily exposure is a potential concern.