Low-cost microcontroller-based device to measure kaolin clay concentrations for iso sprayer cleanout tests

Authors: Jeon, Hongyoung; Zhu, Heping

Submitted to: Applied Engineering in Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/22/2021
Publication Date: 1/20/2022
Citation: Jeon, H., Zhu, H. 2022. Low-cost microcontroller-based device to measure kaolin clay concentrations for iso sprayer cleanout tests. Applied Engineering in Agriculture. 38(1): 135-143. https://doi.org/10.13031/aea.14764.
DOI: https://doi.org/10.13031/aea.14764

Interpretive Summary: Sprayers from US manufacturers required to meet various ISO standards including cleanout standard to export their sprayer to overseas. Nevertheless, current ISO cleanout standard contains vague information on analyzing samples from ISO standard tests. Due to this vagueness, US spray equipment manufacturers were unable to properly test their sprayers if they meet ISO standard or not. Customized apparatus was developed to address this issue, and the apparatus was evaluated for its performance as a tool to assay samples from ISO standard tests assuming kaolin clay as a test material. The study outcomes showed the apparatus had sufficient performance to detect testing materials and the logarithmic regression model developed from its outcomes showed less than 20% of prediction errors and prediction variations. This study outcome will be useful to US spray equipment manufacturers to evaluate their future sprayers under the ISO standard.

Technical Abstract: A simple and low-cost apparatus with operating hardware and software was developed for analyzing samples from ISO 22368 sprayer cleanout tests. The apparatus could measure ASP® 602 concentrations of residue samples from the sprayer cleanout tests with measurement variations, a coefficient of variations (CV), less than 4 %. Sensitivity analysis of the apparatus carried out to understand the measurement limits, and the results showed that the limit of quantification of the apparatus was 13 to 22.5 ppm depending on sample variations which were sufficient for assaying residue samples from ISO 22368 tests. The measurement variations were also affected by homogeneity of the samples. Several prediction models were developed with the apparatus outputs, and prediction accuracy (approximation error) and measurement variations (CV) of the models were validated with additional ASP® 602 samples. The prediction results from the models had a wide range of approximation errors and the results showed approximation errors from 2.6 % to 26.2 % with CV from 3.0 to 33.4 % with the models for a prediction ranges from 0 to above 500 ppm, while considering the results above limit of quantification. The models for a prediction range from 0 to 250 ppm showed the error from 3.9% to 19.7% with CV from 7.5% to 27.5%, under the same consideration. The logarithmic prediction model with the prediction range from 0 to 250 ppm showed most acceptable performance in terms of approximation error and CV that were less than 20%.