New UOG chemistry lab instrument can identify unknown substances

New UOG chemistry lab instrument can identify unknown substances

New UOG chemistry lab instrument can identify unknown substances

(From left) UOG chemistry faculty Dr. John Limtiaco, Dr. Bulan Wu, and Dr. Maika Vuki and laboratory supervisor and lead technician Ezra Cervera in the Chemistry Teaching & Instrumentation Lab.
The gas chromatograph mass spectrometer, known as GC-MS for short, is an analytical instrument that can separate complex chemical mixtures and identify the individual substances.
Chemistry Program Chair Dr. Maika Vuki teaches UOG chemistry faculty how to use the Chemistry Lab’s new gas chromatograph mass spectrometer.

A new scientific instrument at the University of Guam is bringing a bit of a “CSI” vibe to the Chemistry Teaching & Instrumentation Lab in the Science Building.

Installed this past April, the Shimadzu-model gas chromatograph mass spectrometer, or GC-MS for short, is an analytical instrument that can separate complex chemical mixtures through the gas chromatograph (GC) process and conclusively identify the individual substances through the mass spectrometer (MS) process.

“The GC-MS instrument can analyze the sample and provide the identity and the quantity of the compound with a high degree of accuracy and precision,” said Dr. John Limtiaco, assistant professor of chemistry.

But more than creating the illusion of being a detective on a crime investigation television series, the instrument provides students with hands-on experience using a tool that is central to many professions. Additionally, it opens possibilities for researchers who can now conduct on-the-spot chemical analyses.

Classroom and workforce applications

Photo of Dr. John Limtiaco and the GC-MS instrument
Assistant Professor of Chemistry Dr. John Limtiaco and Associate Professor of Chemistry Dr. Bulan Wu discuss the functions of the Chemistry Lab’s new GC-MS instrument.
In the professional world, the GC-MS has applications in criminal forensics, law enforcement and drug testing, explosives investigations, environmental monitoring, and airport security.

At UOG, it will primarily be used for instruction in upper-level, instrumentation-based courses, including Organic Chemistry, Analytical Chemistry, Instrumental Analysis, and Forensic Chemistry. Eventually, the faculty hope to propose a master’s level chemistry program in which the GC-MS would be a key component.   

Incorporation of the new GC-MS will significantly enhance the teaching and learning effectiveness of [my Laboratory Techniques in Organic Chemistry] courses,” said Dr. Bulan Wu, associate professor of chemistry. “We can analyze both the product and side products through GC-MS, leading to a deep understanding of the reaction mechanisms.

Five chemistry and one biology faculty have completed basic training so far for the GC-MS. Other departments and research centers at UOG will soon be invited to learn how to use it as well.

New research opportunities

Photo of Dr. Bulan Wu using a GC-MS
Associate Professor of Chemistry Dr. Bulan Wu inputs a substance into the GC-MS for separation and identification of its chemical elements.
The instrument’s ability to do mass spectrometer detection opens a lot of possibilities for student and faculty research, said Dr. Maika Vuki, professor of chemistry and chair of the Chemistry Program.

“We can study pesticides, a wide range of volatile organic compounds, halogenated compounds, PCBs, PFOs, and PFAs,” he said, referring to various manmade chemicals. “Most of these compounds are regulated and require regular monitoring.”

Limtiaco, for one, is planning to use the instrument to investigate residual pesticide contamination on both local and imported produce and, in a separate study, investigate organic molecule transformations following seawater electrolysis. Wu said she plans to use the GC-MS for natural product research of local medicinal plants and herbs and to synthesize cannabidiol (CBD) and similar substances for anticancer activities.

A long-term goal for the GC-MS is to produce high-quality preliminary data that can be used to leverage large research grants.

Undergraduate and graduate students may utilize the GC-MS for individual research projects and laboratory experiments under the supervision of faculty or laboratory staff. Those interested may coordinate with Dr. Vuki at or Dr. Limtiaco at