Presidential Green Chemistry Challenge: 2009 Greener Reaction Conditions Award
Innovative Analyzer Tags Proteins for Fast, Accurate Results without Hazardous Chemicals or High Temperatures
Innovation and Benefits: Each year, laboratories test millions of samples of food for the presence of protein. Such tests generally use a large amount of hazardous substances and energy. CEM has developed a fast, automated process that uses less toxic reagents and less energy. The new system can eliminate 5.5 million pounds of hazardous waste generated by traditional testing in the United States each year. What's more, it differentiates between protein and other chemicals used to adulterate food, such as melamine.
Summary of Technology: The recent use of melamine to masquerade as protein and adulterate both baby formula in China and pet food in the United States makes accurate testing for protein imperative. The standard Kjeldahl and combustion tests for protein measure total nitrogen, however, and cannot distinguish melamine from protein. Kjeldahl testing uses sulfuric acid, sodium hydroxide, hydrochloric acid, and boric acid along with a catalyst of copper sulfate, selenium, or mercury. U.S. companies generate 5.5 million pounds of hazardous waste annually from Kjeldahl testing. Trained chemists are required to run these tests due to the hazardous materials and high temperatures required.
The SprintTM Rapid Protein Analyzer automates a technique that tags protein directly and provides fast, accurate results. CEM's proprietary iTAGTM solution actually tags protein by attaching only to histidine, arginine, and lysine, the three basic amino acids commonly found in proteins. The proprietary iTAGTM solution contains an acidic group that readily attaches to the basic amino acids; iTAGTM also has an extensive aromatic group that readily absorbs light and appears orange. The iTAGTM bound to the protein is removed from solution by a filter and the remaining iTAGTM is then measured by colorimetry. The SprintTM System ignores any other nitrogen that may be present, including the nitrogen in melamine. As a result, it enables food and pet food processors to be absolutely certain of the bulk protein content of their ingredients and final products for quality control, product safety, and nutritional labeling. SprintTM may be used in the laboratory, on the processing line, or as a rapid check for incoming raw materials. The system does not require a trained chemist to obtain accurate results.
SprintTM uses a green chemistry method: its iTAGTM solution is nontoxic, nonreactive, and water-soluble. It eliminates all of the hazardous waste created by Kjeldahl testing. In addition, SprintTM does not require high temperatures, making it a much safer method than Kjeldahl or combustion techniques. It is easy to operate and can test most samples in 2–3 minutes, compared to 4 hours for a Kjeldahl analysis. It uses disposable filters and recyclable sample cups and lids; all other parts of the system that touch the sample are self-cleaning. Remarkably fast, accurate, cost-effective, and safe, SprintTM is poised to become the method of choice for protein testing. The methods it automates are approved by AOAC (Association of Analytical Communities) and AACC International (previously: American Association of Cereal Chemists). It was commercialized in January 2008.
Podcast on the technology:(MP3, 1.1 MB, 1:10 minutes), Narrator: Dr. Richard Engler, US EPA.