Spray drift deposition comparison of fluorimetry and analytical confirmation techniques

Abstract

Tracer dyes are often used as surrogates to characterize pesticide spray drift and it is assumed that they accurately reflect analytical measurement of active ingredients; however, the validity of this assumption remains inconclusive. Consequently, the influence of measurement technique on the magnitude of deposition of spray drift was investigated using spray drift samples evaluated by traditional analytical techniques (HPLC–MS/MS) and fluorimetry (1,3,6,8‐pyrene‐tetra sulfonic acid tetrasodium salt dye tracer). The experiment was conducted in a low‐speed wind tunnel under controlled meteorological conditions. The herbicide mesotrione was sprayed through three spray air induction nozzles (anvil deflector flat fan TTI11004; flat fan AI11004; flat fan AIXR11003). Spray drift deposition samples were collected using stainless steel discs pairs placed side by side in the center of the wind tunnel at distances of 5, 10, 20, 30, and 40 ft (1.5, 3.1, 6.1, 9.1, and 12.2 m) from the spray nozzle. The analytical technique determined pesticide concentration on one disc per pair, and the other was evaluated by fluorimetry. The experimental results, analyzed using the linear split‐split plot model, revealed that median deposition concentrations were 15% higher using the tracer dye fluorescence method relative to the analytical method, potentially due in part to procedural recovery inefficiencies of the analytical method (the mean overall procedural recovery result and RSD was 87% ± 6.4% (n = 12). This relationship was consistent and held true for the three nozzle types at all distances within the wind tunnel. © 2021 Society of Chemical Industry.

Effect of oil‐based emulsion on air bubbles in the spray sheet produced through the air‐induction nozzle

“…Compared with the spray velocity, the surface tension has a more significant effect on average size of air bubbles. (3) The interaction between the oil droplet and the air bubble is supposed to be the third reason responsible for the decrease in average size of air bubbles in the sheet of the oil-based emulsion spray. Gradients of surface tension with the oil droplet at the air-liquid interface lead to a Marangoni effect, which causes the spreading of the oil droplet.…”

S-Metolachlor Volatilization from Plants within a Flux Chamber

“…The chambers (with the group of plants) were the main units (whole plots) in a completely randomized design, and the repeated measurements on the chambers are equivalent to subplot treatments with no randomization to the treatment factor. The linear model for the split-plot experiment , is where y ijk is the response (measured flux) at time j on chamber k in treatment group i ; μ is the overall mean; α i is the random effect of treatment i , η k ( i ) is a chamber random error nested in chamber treatment; β j is a fixed effect of measurement occasion j ; (αβ) ij is a random interaction effect of treatment i with measurement occasion j ; and ϵ k ( ij ) is random error nested in chamber treatment i at measurement occasion j . The whole plot (chamber) and subplot (measurement occasion) errors are assumed to be independent, normally distributed random errors with mean 0 and variances σ η 2 and σ ϵ 2 , respectively.…”

Visualization of the evolution of bubbles in the spray sheet discharged from the air‐induction nozzle

“…The air‐induction nozzle, which is characterized by the forced penetration of air into a droplet, has been successfully used in agricultural engineering. At the same spray pressure and pesticide flow rate, the air‐induction nozzle creates large droplets relative to those released from standard flat‐fan nozzles, giving rise to lower drift potential 1–3 . Furthermore, large droplets containing bubbles decompose into small droplets when they impact the target, leading to increased retention and spreading effects 4,5 .…”

“…At the same spray pressure and pesticide flow rate, the air-induction nozzle creates large droplets relative to those released from standard flat-fan nozzles, giving rise to lower drift potential. [1][2][3] Furthermore, large droplets containing bubbles decompose into small droplets when they impact the target, leading to increased retention and spreading effects. 4,5 Differences between the air-induction and standard flat-fan nozzles have been investigated in terms of droplet size distribution, droplet velocity and drift potential.…”