Submitted to: Applied Engineering in Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 5, 2013
Publication Date: March 21, 2014
Citation: Hoffmann, W.C., Fritz, B.K., Ledebuhr, M. 2014. Evaluation of 1, 3, 6, 8-pyrene tetra sulfonic acid tetra sodium salt (PTSA) as an agricultural spray tracer dye. Applied Engineering in Agriculture. 30(1):25-28. Interpretive Summary: Spray application researchers commonly have used tracer dyes in place of active ingredients to measure the movement of agricultural sprays from the sprayer to the intended targets. However, new tracer dyes are needed that have increased solubility, stability to ultraviolet radiation, and recovery. We evaluated a new tracer dye, abbreviated as PTSA, and found it to be highly soluble in the spray solution, stable in sunlight, and recoverable from plant and artificial surfaces. The data presented will allow applicators and researchers to confidently use PTSA in their spray application research studies.
Technical Abstract: The ability to measure spray deposition and movement with the use of tracer materials is a necessity for agricultural application research. Ideally, any tracer material used is highly soluble in the solution being sprayed, easily recoverable from both artificial and plant samples, stable in solution and not easily or quickly degraded in sunlight. The objective of this work was to evaluate 1, 3, 6, 8-pyrene tetra sulfonic acid tetra sodium salt (PTSA) for these properties. Comparison of four solvents showed that a 10% isopropyl alcohol solution provided the maximum recovery of PTSA deposits. Once in solution, PTSA proved to be highly stable, with no significant degradation after a week. Exposed to sunlight, PTSA deposits degraded less than 5-6% in the first 20 minutes and less than 15-20% after an hour. Examining recoverability from a variety of plant samples averaged approximately 80% recovery of total PTSA deposits. In addition to being readily available and affordable, PTSA proved to be an excellent option for agricultural spray research.