A New York researcher, David Bauer, created a new kind of molecule that is capable of detecting neurotoxins like nerve gas.

Speaking by telephone to The New York Sun yesterday, he cited two inspirations for his “covalent assembly of a nanodot-based neurotoxin biosensor.”

He said he has worked for the past year and a half in a City College lab with a paramedic who did recovery work at the World Trade Center and talked about the need for a sensor for airborne toxins. A New York City bioterrorism monitor initiative also inspired his project, he said.

“In theory, this could provide a very quick way to determine if someone had been exposed to any neurotoxin,” Mr. Bauer said. “You really hear from people around you that there is a need for this. … I think given the present global climate, things like this really are necessary.”

Mr. Bauer said people often think of chemistry in the abstract. But when he set out to complete this project, he wanted to do something practical with nanotechnology.

He said the idea of protecting against bioterrorism was attractive to him as a lifelong New Yorker, who has lived on the Upper West Side, in Queens, and now in the Bronx. He said his research could also be used to protect farmers from potentially dangerous pesticides.

David Bauer is a 17-year-old senior at Hunter College High School in Manhattan. He lives with his mother, a nurse.

When he’s not in the chemistry lab, he works on a Web site he created, UnitedLiberia.com, which compiles news about Liberia.

He plans to attend the CUNY Honors College next year and hopes eventually to become a professor and do further research.

Mr. Bauer was one of four New York City students out of 40 nationally who were named finalists yesterday in the Intel Science Talent Search.

Two others attend public schools: Olga Pikovskaya of Midwood High School at Brooklyn, and Yingqiuqu Lei of Robert F. Kennedy Community High School at Queens.

“I commend these students on their hard work and commitment to scientific research,” the schools chancellor, Joel Klein, said yesterday, “and I applaud the principals, teachers, and mentors who have guided them in their studies.”

The fourth city Intel finalist, Ling Pan, attends the private Brearley School in Manhattan.

Intel’s announcement came a day after Mr. Klein said he wanted to turn Staten Island Technical High School into a selective school and urged the principal to turn out more Intel finalists. None of the existing selective high schools – Bronx High School of Science, Stuyvesant High School, and Brooklyn Technical High School – produced a finalist this year.

Ms. Pikovskaya, 17, created a biochemistry project that focused on the synthesis, purification, and crystallographic identification of the “riboswitches” that are responsible for gene activation. Ms. Pikovskaya was born in Russia and moved to New York 11 years ago.

Ms. Lei, 18, researched trace element geochemistry in fossil teeth from 57 archaeological sites for her project. She is a recent immigrant from China.

Ms. Pan, 18, researched opioid receptors and ways of increasing drug effectiveness. She, too, was born in China.