By binding to those ions, phosphates also prevent them from forming spotty deposits. And to some extent, they help maintain the proper pH, says Kenneth Doll, a chemist with the U.S. Department of Agriculture's Agricultural Research Service.
Doll, who works in the agency's Peoria, Ill., research center, helped develop a couple of phosphate alternatives several years ago, though they did not make it to market. In one, Doll and a colleague used a combination of sodium aspartate, which is a building block in artificial sweetener, and sorbitol, derived from corn starch. Some companies are trying sodium citrate, a citric acid salt, to replace phosphates.
It is easy enough to develop alternatives, but they are likely to cost more, says Jeff Harwell, a professor of chemical engineering at the University of Oklahoma. Phosphates are plentiful; in the United States, they come primarily from mines in Florida and North Carolina.
Fear not for the humble phosphates, however. They remain a key component in a staggering number of products, ranging from strawberry-flavored milk (by binding to iron, phosphates maintain the pink color) to fertilizer. A major supplier is Innophos Inc., of Cranbury, N.J.
But as for detergents, no longer. And if the industry is lucky, most customers will be like Swarthmore's Murray.
"You know, I have four kids and two dogs," she says. "I'm not really looking for how much it sparkles. I'm happy if it gets put back in the cabinet before the kids pull it out again."
Contact staff writer Tom Avril
at 215-854-2430 or tavril@phillynews.com.
