Robert J. Cotter, Johns Hopkins medical school professor

Robert James Cotter, a Johns Hopkins scientist and professor whose work in mass spectrometry has contributed to discoveries in health and science, died last Monday of heart failure at his home at HarborView in Baltimore. He was 69.

His work, which earned him international recognition, led to advances in the analysis of chemical and biological substances.

His achievements in the field of mass spectrometry "have led to major discoveries in cancer, immune disorders, infectious diseases and metabolic syndromes," said Philip Cole, director of the Department of Pharmacology and Molecular Sciences in the School of Medicine. Dr. Cotter was a professor in the department for more than three decades.

Mass spectrometry is a technique used to identify chemical substances and examine them in tremendous detail. Some of Dr. Cotter's advancements have been incorporated in its commercial applications, Dr. Cole said.

The technique has been used to better understand cancer cells and the immune system, as well as to detect chemical and biological agents that might come from a terrorist or military attack, Dr. Cole said.

"He applied mass spectrometry to everything from molecules to Mars," said a colleague, Jef D. Boeke, director of the High Throughput Biology Center at the Johns Hopkins University School of Medicine.

Dr. Boeke worked with Dr. Cotter on a large team of investigators from several institutions that received more than $17 million in federal grants for their studies, he said.

Dr. Cotter also helped design a mass spectrometry device to allow the Mars Rover to search for signs of prior life on the planet.

His work earned him numerous honors in his field. In 2009, he received the American Chemical Society's Analytical Chemistry Award in Chemical Instrumentation. In 2010, he received the society's Frank H. Field and Joe L. Franklin Award for outstanding achievement in mass spectrometry. Last year, he received the American Society for Mass Spectrometry's Award for Distinguished Contribution in Mass Spectrometry. .

"He brought humor to everything he did. He loved and cared for people in his laboratory and people throughout Johns Hopkins," said Dr. Cole.

The oldest of seven children, Dr. Cotter was born July 15, 1943, in Washington, and was the oldest of seven children. His father, Robert Joseph Cotter, was then a lawyer with the Army; his mother, Rita Mary Lang Cotter, stopped teaching to raise the couple's children. His father died in 1990.

Dr. Cotter grew up in Abington, Mass., and graduated from Boston College High School, in Boston, in 1961. He received a bachelor of science degree from the College of the Holy Cross in Worcester, Mass., in 1965.

He earned a doctorate in chemistry from the Johns Hopkins University in 1972.

Dr. Cotter then taught at Towson University and was on the faculty of Gettysburg College. In 1978, he joined the faculty at Johns Hopkins' School of Medicine. He has been teaching biophysics, pharmacology and analytical methods to graduate and medical students.

A first marriage ended in divorce. Dr. Cotter met his wife of 28 years, Catherine Fenselau Cotter, when both worked in mass spectrometry at Hopkins. She teaches in the field at the University of Maryland College Park.

She said he enjoyed playing the piano, mostly jazz and lounge music, for friends. He also enjoyed putting to use skills he learned from his grandfather in home renovations, which included working as a graduate student to open the People's Free Medical Clinic on Greenmount Avenue, she said.

"He loved bicycling," said his son, Bruce Cotter, recalling that his father took him bicycling around Baltimore in his youth.

In later years, he took to bicycling on the C&O; Canal with his wife, Catherine Cotter said. The couple bicycled its 185-mile length — and, after realizing they were spending more time in the car to reach their destination than they spent at it, bought a vacation home in Washington County along the canal. He did volunteer work for the C&O; Canal Association..

"He had a good eye for art" and he visited galleries in California to find paintings for their home, his wife said. Most were modern impressionistic styles from around the world.

Services and burial were private. A memorial gathering is scheduled for 6 p.m. Monday at the West Lecture Hall of the Wood Basic Science Building of the Johns Hopkins Medical School.

Survivors include his wife; his mother, who lives in Bow, N.H.; his son, who lives in Baltimore; stepsons Thomas Fenselau and Andrew Fenselau of Palo Alto, Calif.; brothers Brian Cotter of Danbury, Conn., Barry Cotter of Jacksonville, Fla., Chris Cotter of Sandwich, Mass.; and Greg Cotter of Marshfield, Mass.; a sister, Julie Cotter Bryant of Bow, N.H., and two grandchildren. A brother, Shawn Cotter, died in 2007.

andrea.siegel@baltsun.com