Progress 06/01/07 to 01/31/09
Outputs
OUTPUTS: The ultimate goal beyond Objective 1 was to detect Humulene in an actual crop enclosure in the presence of the gases in the headspace over corn as it is stored in the enclosure using Sensor Development Corporation's (SDC) prototype sensor. The sensor was taken to Purdue University and tested in conjunction with the 1000 bushel corn bin located on the Purdue University farm. The bin was filled approximately three fourths full with corn from their farm. The gas from the bin was pumped out of the bin with an air pump and passed over the sensors and the base line sensor response established. An amount of about 80 ppb of the MVOC was released into the bin air stream. The sensor response to the MVOC was as expected and clearly demonstrated that the MVOC could be detected in an environment commonly existing in a corn bin atmosphere. Furthermore, SDC set up a computer and radio receiver in a remote weigh house approximately 120 yards from the corn bin. The computer received the wireless signal from the SDC sensor and displayed the resistance change and the temperature of the chips simulating transferal of data in the final application. As a result of the success of the Purdue University field test both The Andersons and Cargill have agreed to be beta test sites. The results have been shared with potential customer beta test sites at trade shows followed up with individual meetings. Objective 2 relates to indentifying the gases present in the headspace above the corn. It is important to identify other components as well which would be considered interferents or background gases. Samples of the gas in the headspace of non-toxigenic corn and toxigenic corn producing aflatoxin were collected and analyzed using GC/Mass Spec for gases not common between the two types of samples. This sample collection and GC/Mass Spec work were done at Purdue University and the USDA Southern Region Research Center. The analysis of the data was done at SDC. This work confirmed the presence of sesquiterpenes in the head space. It also identifies potential interferent gases and other potential marker gases. This information has yet to be published other than in the Phase I final report. PARTICIPANTS: The Project Director for this project was Robert N. Mansfield, Jr. "Rocky" as he is known at Sensor Development Corporation (SDC) led a team of engineers and scientists from inside SDC and other contributors from various universities, research groups and other companies through to its completion. The SDC team included Dr. Robert F. Scarr, Sr. Research Chemist and Samuel F. Reichert, Sr. Product Engineer. Dr. Scarr had overall responsibility for the gas analysis portion of the project including determining potential marker, background and interferent gases that could be found in a crop enclosure. Mr. Reichert worked in the area of sensor chip testing and interfaced with Dr. Mark R. De Guire, Assistant Professor Department of Materials Science and Engineering and his PhD candidate Ling Tang at Case Western Reserve University, Cleveland, Ohio, as they made the sol gels with and without catalysts for coating the sensor chips that are used in SDC's prototype and lab testing set up. The sensor chips were tested in SDC's lab for best bet combinations for detecting the marker gas. This work led to the successful field trial at Purdue University's farm. Many individuals outside of Sensor Development Corporation contributed their time and talent to this project. Their contribution is acknowledged here. At Purdue University College of Agriculture, West Lafayette, Indiana, Dr. Charles P. Woloshuk, Professor of Plant Pathology, Botany and Plant Biology Department ran many key experiments using SDC's prototype sensor in the lab to confirm the presence of susquiterpenes in toxic corn with aflatoxin growing. The susquiterpenes were not present in non-toxic corn. Dr. Johnselvakumar Lawrence, Post Doc., set up the field trial at Purdue University's farm. Dr. Dirk E. Meir, Professor and Head Department of Grain Science & Industry, Kansas State University, Manhattan, Kansas formerly of Purdue University oversaw the field trial. The Food and Feed Safety Research group at the USDA Southern Regional Research Center, New Orleans, Louisiana led by Dr. Thomas E. Cleveland, Director Southern Regional Research Center, formerly Director Food and Feed Safety Research collected samples of volatiles from agar with and without A. flavus, the mold that produces aflatoxin, for gas chromatograph - mass spectroscopy analysis. Mr. Anthony J. De Lucca, Microbologist Food and Feed Safety Research supervised the undergraduate students that ran the volatile gas samples he prepared. Dr. Stephen M. Boue, Research Chemist, Food and Feed Safety Research provide the gas chromatograph - mass spectroscopy equipment for the analysis. Edward J. Rapp, President Flocel, Cleveland, Ohio designed the electronics for SDC's prototype, built the working prototype and encoded the software used by the prototype and lab test station. TARGET AUDIENCES: Not relevant to this project. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
The ultimate goal beyond Objective 1 was to detect sesquiterpenes in an actual crop enclosure in the presence of the gases in the headspace over corn as it is stored in the enclosure using Sensor Development Corporation's prototype sensor. The prototype sensor contains four sensor chips. Some are coated with catalyst combined with the nano-crystalline tin oxide and others are without catalyst. The gases in the headspace above the corn were pumped from the corn bin at 1,500 cubic centimeters per minute into the prototype through a dual flow controller. Into the second side of the dual flow controller, a tank containing a susquiterpene was connected. The susquiterpene flow rate was set at 85 ppb and turned on and off as desired. A 1,000 bushel bin at Purdue University's Agricultural Research Farm was used for this demonstration. In order to achieve this result, Objective 1 was a necessary precursor. To coat the sensor chips with catalyzed nano-crystalline tin oxide, techniques had to be developed to add the catalysts to the tin oxide sol gel before applying it to the sensor chip. Once the catalyst was successfully added to the tin oxide sol gel, a procedure for applying the sol gel had to be developed. Eventually two procedures were settled on and tried. The combinations of application procedure to the sensor chip and catalyst were tested in SDC's lab for response to susquiterpenes and other interferent gases. The goal of Objective 2 was to substantiate volatiles from previous work by Zeringue as markers for aflatoxin and to determine if other volatiles could be used as markers for aflatoxin detection. Furthermore, it was important to identify other components as well which would be considered interferents or background gases. Samples of the gas in the headspace of non-toxigenic corn and toxigenic corn producing aflatoxin were collected and analyzed using GC/Mass Spec for gases not common between the two types of samples. This sample collection and GC/Mass Spec work were done at Purdue University and the USDA Southern Region Research Center. The analysis of the data was done at SDC. The electronic chip sensors for A. flavus-produced volatiles will detect the five compounds that are most produced by this fungus as identified by the gas analysis from the USDA and Purdue. This will reduce the need, and hence overall cost, for sensors for all identified volatiles. Since these units will be small they can be easily located in any area where grain is stored and since the units can be either "hard-wired" or battery operated for power and data (e.g., power status, volatile detection, signal strength) transmission, purchasers of this technology will have the flexibility needed to accommodate their needs. This technology will be the first to offer the corn storage industry a real-time warning of A. flavus growth and will reduce or eliminate the need for costly and time consuming analyses for aflatoxins. This real-time capability will allow the users to reduce the possibility of contaminated corn being mixed with good, wholesome corn and thereby reduce food, feed and economic losses due to a large, mixed corn batch contaminated with aflatoxin.
Publications
- No publications reported this period
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