Depletion kinetics and concentration- and time-dependent toxicity of a tertiary mixture of amitraz and its major hydrolysis products in honeybees

Rapid and sensitive quantitation of amitraz in orange, tomato, and eggplant samples using immunochromatographic assay

Amitraz (AMT) is a broad-spectrum formamidine insecticide and acaricide. In this study, we produced an anti-AMT monoclonal antibody (mAb) with high performance. The half-maximal inhibitory concentration of the anti-AMT mAb was 4.418 ng/mL, the cross reactivity with other insecticides was negligible, and an affinity constant was 2.06 × 109 mmol/L. Additionally, we developed an immunochromatographic assay for the rapid detection of AMT residues in oranges, tomatoes, and eggplants. The cut-off values were 2000 μg/kg in oranges and tomato samples and 1000 μg/kg in eggplant samples and the calculated limits of detection were 14.521 μg/kg, 6.281 μg/kg, and 3.518 μg/kg in oranges, tomatoes, and eggplants, respectively, meeting the detection requirements for AMT in fruits and vegetables. The recovery rates ranged between 95.8 % and 105.2 %, consistent with the recovery rates obtained via LC-MS/MS. Our developed immunochromatographic assay can effectively, accurately, and rapidly determine AMT residues in oranges, tomatoes, and eggplants.

A novel equal frequency sampling of factor levels (EFSFL) method is applied to identify the dominant factor inducing the combined toxicities of 13 factors

The research framework combining global sensitivity analysis (GSA) with quantitative high-throughput screening (qHTS), called GSA-qHTS, provides a potentially feasible way to screen for important factors that induce toxicities of complex mixtures. Despite its value, the mixture samples designed using the GSA-qHTS technique still have a shortage of unequal factor levels, which leads to an asymmetry in the importance of elementary effects (EEs). In this study, we developed a novel method for mixture design that enables equal frequency sampling of factor levels (called EFSFL) by optimizing both the trajectory number and the design and expansion of the starting points for the trajectory. The EFSFL has been successfully employed to design 168 mixtures of 13 factors (12 chemicals and time) that each have three levels. By means of high-throughput microplate toxicity analysis, the toxicity change rules of the mixtures are revealed. Based on EE analysis, the important factors affecting the toxicities of the mixtures are screened. It was found that erythromycin is the dominant factor and time is an important non-chemical factor in mixture toxicities. The mixtures can be classified into types A, B, and C mixtures according to their toxicities at 12 h, and all the types B and C mixtures contain erythromycin at the maximum concentration. The toxicities of the type B mixtures increase firstly over time (0.25 ∼ 9 h) and then decrease (12 h), while those of the type C mixtures consistently increase over time. Some type A mixtures produce stimulation that increases with time. With the present new approach to mixture design, the frequency of factor levels in mixture samples is equal. Consequently, the accuracy of screening important factors is improved based on the EE method, providing a new method for the study of mixture toxicity.