Entesar Al-Hetlani Analytical Chemistry Makes Every Drop Count

Entesar Al-Hetlani is pioneering analytical chemistry in Kuwait, realizing the goals she dreamed of as a student. “I used to watch all these TV shows where they would solve crimes,” said Al-Hetlani, who is now an analytical chemist at Kuwait University.
“I’d see them using the same instruments we had in our lab. I know they weren’t realistic, but there was something very attractive about it. I saw chemistry being used for something real and relevant, and I just wanted to do that.” Al-Hetlani became interested in analytical chemistry at the University of Hull, England, where she went on a scholarship as a graduate student, and the program they offered was analytical chemistry. “I found it really fascinating. If you can analyze something to determine what’s in it and how much, then you can answer so many questions,” the winner of the Jaber Al-Ahmad Award for Young Researchers 2020 from the Kuwait Foundation for the Advancement of Sciences (KFAS) said.
Her interest is partly driven by the challenge of solving puzzles. Comparing scientific research to solving a crime, Al-Hetlani said, “you have several clues and all of them are important, but it’s up to you to decide which ones are more important.” Chemical analysis can help by wringing as much information as possible from each clue. For example, fingerprints have been a staple of sleuthing for over a century, but experts like Al-Hetlani can glean so much more from them than we could before.
Al-Hetlani said that fingerprints are “more than just an impression,” and analyzing them in different ways can provide information about a person’s ethnicity or gender, as well as other details. Some of her research, which was funded by KFAS, has focused on improving our ability to use fingerprints to learn not about who a person is, but rather, what they were handling.
Detecting and identifying traces of drugs from fingerprints could be immensely useful to determine what happened at a crime scene, especially as Kuwait faces a growing drug problem. Al-Hetlani accomplishes this by adjusting a technique known as SALDI, in which a sample is ionized by a laser, and the ionized molecules are then identified by mass spectrometry, a highly discriminating technique. Al-Hetlani wondered whether this method could be improved by dusting the fingerprints with metal oxide nanoparticles. When they tested the idea, Al-Hetlani’s team found that it reduced background noise that could obscure the analysis. The researchers were able to reliably detect traces of drugs on fingerprints after a week, as long as the samples were stored at low or moderate temperatures.
Now her team is working to squeeze even more information out of fingerprints; one student is working to identify traces of cosmetics in fingerprints, perhaps even pinpointing the specific brand, while another is trying to detect more information about ‘endogenous characteristics’— features of the person who left the print. Al-Hetlani also worked out how to learn something about a person from a small sample of saliva. She took a sabbatical in Igor Lednev’s lab at the University at Albany, State University of New York, to learn a technique known as Raman spectroscopy. In Raman spectroscopy, a sample is illuminated with a laser, and changes in the energy of scattered photons are used to determine the molecular composition of the sample. Lednev was impressed with Al-Hetlani and said, “We immediately recognized that she had an excellent background and strong expertise in spectroscopy and spectrometry. She did excellent research in my lab, and we published a joint paper in the top journal in the field.”
The paper, which made the cover of that issue, was about figuring out whether a saliva trace came from a smoker. By training a machine learning system on Raman spectra from smokers and non-smokers, they developed a model that could accurately pinpoint where a sample had come from. “This could be very helpful for law enforcement agencies, especially at the beginning of an investigation, because it would give them additional information about potential suspects,” said Lednev. Handheld Raman spectrometers are available, meaning the analysis could be run directly at the crime scene. While on her sabbatical, Al-Hetlani also developed an improved method to diagnose celiac disease.
Lednev’s team could already use Raman spectroscopy to diagnose celiac disease on the basis of a blood sample, but their approach required statistical analysis to detect the tiny changes in the Raman spectrum. By adjusting the wavelength of the lasers used, Al- Hetlani found conditions that produce spectra that were much easier to analyze. “Now, the differences are very significant. You can see them with the naked eye,” said Lednev. The findings are exciting, but Lednev notes that they need to be validated with a larger sample set and then published. “We’re even considering patenting it,” he said.
The underlying theme in much of Al- Hetlani’s work has been getting as much as possible out of limited material. That’s certainly true of another contribution she has made to tackling drug abuse. Using the same techniques as they had for fingerprint analysis, Al-Hetlani and her team were able to determine whether a drink had been spiked from just a few millionths of a liter—less than a drop.
Drug analysis has always been important to Al-Hetlani. “I think it’s a problem now. It was a problem in the past, and it will always be a problem that will only get worse with time,” she said. “If we have people who can work on this and keep up with the changes by using technology, then maybe we can contain the situation.”
Getting as much as possible out of every clue is vital in forensics, where material is both limited and irreplaceable. The other significant advantage of the techniques Al-Hetlani is developing is their speed. She says that forensics experts in Kuwait are overwhelmed by their caseload, so every boost in speed Raman spectrum. By adjusting the wavelength of the lasers used, Al- Hetlani found conditions that produce spectra that were much easier to analyze. “Now, the differences are very significant. You can see them with the naked eye,” said Lednev. The findings are exciting, but Lednev notes that they need to be validated with a larger sample set and then published. “We’re even considering patenting it,” he said. The underlying theme in much of Al- Hetlani’s work has been getting as much as possible out of limited material. That’s certainly true of another contribution she has made to tackling drug abuse. Using the same techniques as they had for fingerprint analysis, Al-Hetlani and her team were able to and efficiency helps. In the long run, she hopes a collaborative center between Kuwait University and the Ministry of Interior can bring together researchers and forensics experts to push analyses forward and discover new applications.